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  • Ubuntu 13.04 to 13.10: Filesystem check or mount failed [migrated]

    - by SamHuckaby
    I attempted to upgrade from Ubuntu 13.04 to 13.10 today, and mid upgrade the system started flaking out, and eventually locked up entirely. I was forced to restart the computer, and am now unable to get the computer to boot up at all. When I boot currently, it takes me to the GRUB menu, and I can choose to boot normally, or boot in an older version. I have tried several things, which I list below, but no matter what, when I try to finish booting into Ubuntu, I receive the following error: Filesystem check or mount failed. A maintenance shell will now be started. CONTROL-D will terminate this shell and continue booting after re-trying filesystems. Any further errors will be ignored root@ubuntu-computername:~# I have fun fsck -f and everything appears correct, no errors are reported. and it passes all 5 checks. If I run fdisk -l then I get the following information: Disk /dev/sda: 320.1 GB, 320072933376 bytes 255 heads, 63 sectors/track, 38913 cylinders, total 625142448 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 4096 bytes / 4096 bytes Disk identifier: 0x00010824 Device Boot Start End Blocks Id System /dev/sda1 * 2048 608456703 304227328 83 Linux /dev/sda2 608458750 625141759 8341505 5 Extended Partition 2 does not start on physical sector boundary. /dev/sda5 608458752 625141759 8341504 82 Linux swap / Solaris Disk /dev/sdb: 320.1 GB, 320072933376 bytes 255 heads, 63 sectors/track, 38913 cylinders, total 625142448 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 4096 bytes I/O size (minimum/optimal): 4096 bytes / 4096 bytes Disk identifier: 0x0fb4b7e8 Device Boot Start End Blocks Id System /dev/sdb1 8192 625139711 312565760 7 HPFS/NTFS/exFAT I am considering just installing a new OS on the other disk, that currently has nothing on it, and then just attempting to scrape my data off the old disk (thankfully I didn't encrypt the files). Really my question is this: Can I salvage this Ubuntu install, or should I give up and just reinstall?

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  • scan partition for bad blocks

    - by user22559
    Hello everyone I have a hard disk with bad sectors on it. I want to partition the drive so that the partitions are in the good part of the hard disk, and the parts that have bad sectors are not used. The first ~20GB of the hard disk are good. Then comes a ~13GB part that is riddled with bad sectors. After that, the hard disk is good again, but at the very end there is a ~2GB part with bad sectors. I have used an app called "Hdtune" to get this information, and I have created a 19GB c: partition at the beginning of the drive, then skipping the 13GB of bad sectors, then creating the D: partition that spans the rest of the disk, minus the last 2GB. The C: partition works well (i have been using it for a month and i have got no error whatsoever), but the D partition has been giving me problems. Somehow, it seems that I have some bad sectors in the D: partition. I am looking for an app that scans the HDD, finds the bad blocks, and shows them in a map so I can see if they are in the D partition. Or, an app that scans only a specified partition for bad sectors, and then shows in a map where the bad sectors are in the partition. I want to know this so I can resize the D partition so that it is outside of the bad area of the disk.

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  • Formula to calculate probability of unrecoverable read error during RAID rebuild

    - by OlafM
    I need to compare the reliability of different RAID systems with either consumer or enterprise drives. The formula to have the probability of success of a rebuild, ignoring mechanical problems, is simple: error_probability = 1 - (1-per_bit_error_rate)^bit_read and with 3 TB drives I get 38% probability to experience an URE (unrecoverable read error) for a 2+1 disks RAID5 (4.7% for enterprise drives) 21% for a RAID1 (2.4% for enterprise drives) 51% probability of error during recovery for the 3+1 RAID5 often used by users of SOHO products like Synologys. Most people don't know about this. Calculating the error for single disk tolerance is easy, my question concerns systems tolerant to multiple disks failures (RAID6/Z2, RAIDZ3 and RAID1 with multiple disks). If only the first disk is used for rebuild and the second one is read again from the beginning in case or an URE, then the error probability is the one calculated above squared (14.5% for consumer RAID5 2+1, 4.5% for consumer RAID1 1+2). However, I suppose (at least in ZFS that has full checksums!) that the second parity/available disk is read only where needed, meaning that only few sectors are needed: how many UREs can possibly happen in the first disk? not many, otherwise the error probability for single-disk tolerance systems would skyrocket even more than I calculated. If I'm correct, a second parity disk would practically lower the risk to extremely low values. Am I correct?

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  • Is there a way in Windows 7 to disable "journaling"?

    - by Psycogeek
    C:\$extend\$Usn.Jrnl:$J:$data Here is a picture finally. The large strip in the center of the top band is the largest chunk, in the other, grey areas are the various clusters with it. On the right, the big long grey line is $logfile (not paging), and it is 63&nbsb;MB. Paging, 500&nbsb;MB is the dark cyan chunk, next to the yellow MFTres in the inner rings.. The disk was defragged so they could be seen easier. Not all clusters of this type of file are tagged, but the idea is there. The disk is 4k clusters, now about 12 GB size. Each cute little block in the picture is .81 MB and represents 207 clusters. The dkGreen section, is mostly the whole Winsxs pile, also interesting when they keep telling us it doesn't take much disk space. Wikipedia suggests that in previous NT systems "USN journaling" would be turned on when enabled (assumes it could also be turned off?). What aspects, services, or program is working on putting that stuff all over the disk which is known by $jrnl$ type clusters, even if it is not actual USN journaling? Is it possible in a Windows 7 system to completly disable the journaling, and what would be the ramifications of that? On a Windows XP NTFS system, I do not recall seeing the quantity of disk clusters used with these $jrnl$ names, so I do not recall this being necessary in this quantity for an NTFS file system itself? I understand that it would not be there, if it did not have a useful function :-) Information about how wonderful is fine, if that information will help track down what parts of the system create and use it. Change Journals states: Change journals are also needed to recover file system indexing Hmm, that might explain some of them, or why it was left on the disk. A crash while background indexing?

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  • Application (was Firefox) crash on first load on Ubuntu Linux on older Dell Laptop

    - by Ira Baxter
    I've had a Dell Latitude laptop since about 2000 without managing to destroy it. A month ago the Windows 2000 system on it did something stupid to its file system and Windows was completely lost. No point in reinstalling Windows 2000, so I installed an Ubuntu Linux on the laptop. Everything seems normal (installed, rebooted, I can log in, run GnuChess, poke about). ... but ... when I attempt to launch Firefox from the top bar menu icon, I get a bunch of disk activity, the whirling cursor icon goes round a bit and then (WAS: everything stops: icon, mouse. Literally nothing happens for 5 minutes. Ubuntu is dead, as far as I can tell. EDIT : on further investigation, spinning icon, mouse operated by touchpad freeze. There's apparantly a little disk activity occuring about every 5 seconds. I wait 5-10 minutes, behavior doesn't change) A reboot, and I can repeat this reliably. So on the face of it, everything works but Firefox. That seems really strange. The only odd thing about this system when Firefox is booting is that while it has an Ethernet port (that worked fine under Windows), it isn't actually plugged into an Ethernet. As this is the first Firefox boot since the Ubuntu install, maybe Firefox mishandles Internet access? Why would that crash Ubuntu? (I need to go try the obvious experiment of plugging it in). EDIT: I tried to run the Disk manager tool, not that I cared what it was, just a menu-available application. It started up like Firefox, I get a little tag in the lower left saying Disk P*** something had started, and then the same behavior as Firefox. At this point, I don't think its the Ethernet. Is it possible that the Ubuntu disk driver can't handle the disk controller in this older laptop? The install seemed to go fine.

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  • How ZFS handles online replacement in a RAID-Z (theoretical)

    - by Kevin
    This is a somewhat theoretical question about ZFS and RAID-Z. I'll use a three disk single-parity array as an example for clarity, but the problem can be extended to any number of disks and any parity. Suppose we have disks A, B, and C in the pool, and that it is clean. Suppose now that we physically add disk D with the intention of replacing disk C, and that disk C is still functioning correctly and is only being replaced out of preventive maintenance. Some admins might just yank C and install D, which is a little more organized as devices need not change IDs - however this does leave the array degraded temporarily and so for this example suppose we install D without offlining or removing C. Solaris docs indicate that we can replace a disk without first offlining it, using a command such as: zpool replace pool C D This should cause a resilvering onto D. Let us say that resilvering proceeds "downwards" along a "cursor." (I don't know the actual terminology used in the internal implementation.) Suppose now that midways through the resilvering, disk A fails. In theory, this should be recoverable, as above the cursor B and D contain sufficient parity and below the cursor B and C contain sufficient parity. However, whether or not this is actually recoverable depnds upon internal design decisions in ZFS which I am not aware of (and which the manual doesn't say in certain terms). If ZFS continues to send writes to C below the cursor, then we are fine. If, however, ZFS internally treats C as though it were gone, resilvering D only from parity between A and B and only writing A and B below the cursor, then we're toast. Some experimenting could answer this question but I was hoping maybe someone on here already knows which way ZFS handles this situation. Thank you in advance for any insight!

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  • Cloned Win7: Keyboard doesn't work

    - by Marc
    I cloned my old Windows7 hard disk to a shiny new Seagate Momentus XT 500GB using the free EaseUs Disk Copy tool on my laptop. After the clone process I used the Windows 7 installation disc to start the automatic startup repair. This took maybe 15 minutes and then my cloned disk was able to start. Now the cloned disk boots until the login screen and then I can't do anything because my keyboard just doesn't work. I tried connecting an external USB keyboard but this didn't help. The mouse is working fine. Note that the keyboard works fine in BIOS and in the Windows startup options menu. I booted into safe mode and again the keyboard is not working at all. I also noticed that the letters "Press CTRL+ALT+Delete to login" are now shown in italic font but they used to be shown non-italic on the original disk. I have now replaced the clone with the original disk again and from here everything works fine. Doesn't anybody have an idea how I can get my keyboard back?

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  • SATA DVD drive refuses to read movie DVDs

    - by poke
    Hey, I have a problem with my DVD Drive (Asus DRW-2014L1T, most current firmware installed) on Windows 7 x64. When I insert a DVD movie and Windows starts to access the drive (for autoplay, or when I manually click on the drive icon), my computer hangs up in a particular way, while trying to read the disk. Explorer stops reacting and several programs won't run or their launch is horribly delayed (like the device manager). In th end, I can't access the movie and can't even eject the disk (probably because Windows is still trying to access it). To get the disk out of the drive I then have to reboot (which sometimes doesn't work either) and eject the disk before Windows boots. BIOS recognizes the drive just fine, and Windows is also able to read data disks (tried it with some software disks), but just refuses any movies. I have checked the region code in the device manager, but it is correct. My notebook is reading the disks just fine btw.. I remember having the same problem with an older drive as well, but I don't remember what I did to make it work again (maybe I didn't even fix the problem back then). I do remember however that booting with the disk inserted made Windows recognize the disk, however this doesn't work in this situation either. Do you have any idea what to do to fix that problem?

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  • Western Digital HDD disappears and reappears in BIOS

    - by tbkn23
    I know many people asked about similar problems, but I have a very specific case where I can't understand what's going on... I have a 3TB Western Digital Caviar Green disk connected in my Desktop, that also has a seagate 1.5TB disk and 2 SSD drives (OCZ and Sandisk). After working fine for quite some time (probably more than a year), suddenly my Caviar Green drive disappeared from windows. I checked the BIOS, and it wasn't there either. I opened my PC, played with the connectors, power, etc, but nothing helped. Even tried switching connectors with those of the 1.5TB disk, and nothing changed, the 1.5TB seagate was there, but the 3TB WD was not. Ok, now for the strange part. I have another desktop at home, so I took out my 3TB drive, connected it there, and it worked fine! I copied the most important files out of it, and then made another attempt in the original desktop. Surprise! It now appeared in the BIOS and worked fine! I even ran the SMART test with the WD tools and it said everything was intact. It doesn't end here. After leaving it overnight in the original desktop, it disappeared again in the morning. I repeated the entire process, connecting it to the second desktop, and there it is again working fine. Now for my question... Whats going on? The disk seems to be appearing on/off in my original Desktop, while other drives there work fine. SMART test says the disk is fine. Any ideas? Is the disk defective and should be replaced? Or maybe there's a problem with the controller in the desktop? I'm using a Gigabyte GA-880GA-UD3H motherboard and tried connecting the drive to both bridges (SATA2 and SATA3 bridges). Thanks EDIT: Power options are set never to turn off hard drives:

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  • Boot records messed on dual boot (win7 and ubuntu) machine with SSD and HDD

    - by Michael
    i have a lenovo ideapad y570 with two hard drives: SSD and normal HDD both managed by RapidDrive and windows 7 pre-installed. First, i have shrunk my 500 GB HDD a little bit to make some place for a linux installation. Then i installed linux mint 12 to it, also installed grub onto the drive (dev/sdb). Installation programm has not allowed me to install grub on sda. Then i replaced linux mint with ubuntu 12.04 but installed grub onto the SSD (which is dev/sda and was the default-option). After that i could boot into my windows, only ubuntu worked. So i did a research, and tried: rewriting mbr of windows into sda1, reinstalling grub, replacing grub2 with grub-legacy, and now i think my partitions table are totally messed. Here is fdisk -l output: ubuntu@ubuntu:~$ sudo fdisk -l Disk /dev/sda: 64.0 GB, 64023257088 bytes 255 heads, 63 sectors/track, 7783 cylinders, total 125045424 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000 Device Boot Start End Blocks Id System /dev/sda1 * 2048 411647 204800 7 HPFS/NTFS/exFAT /dev/sda2 411648 1009430959 504509656 7 HPFS/NTFS/exFAT Disk /dev/sdb: 500.1 GB, 500107862016 bytes 255 heads, 63 sectors/track, 60801 cylinders, total 976773168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x5e5d1cc8 Device Boot Start End Blocks Id System /dev/sdb1 * 1979 884389887 442193954+ 12 Compaq diagnostics /dev/sdb2 884391934 976771071 46189569 5 Extended /dev/sdb5 884391936 937705471 26656768 83 Linux /dev/sdb6 937707520 967006207 14649344 83 Linux /dev/sdb7 967008256 976771071 4881408 82 Linux swap / Solaris I also cant mount any windows partitions to recover data. And when i open gparted, the whole sda-disk appears unallocated and it states "can not have a partition outside the disk!", also the end-sector address of /dev/sda2 confuses me. If i boot from the SSD, it throws some mbr error and wont boot, if i boot from the HDD, i only get the grub bash. How do i restore the partition tables? I can boot only from a live-cd at the machine. Thanks for any help.

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  • Windows Home Server 2011, No disks "suitable for a backup destination"

    - by Scott Beeson
    I recently installed Windows Home Server 2011 and love it. However, when I try to set up server backups, it says no suitable disks are available. Initially, before I set up my RAID, it found one of my twin drives and said it would work. Once I set up the mirroring, that one is no longer available (obviously). However, I have an internal SATA 1TB drive and an external USB2.0 1TB drive hooked up. Both are recognized by Disk Management. WHS11 still says nothing suitable for backups. The two drives details are as follows: Edit to clarify: The system partition is on Disk 0, not listed below. The two below are the two that SHOULD be available for system backups. Disk 1: Dynamic "Data" (D:) 931.51 GB NTFS, Healthy Disk 3: Basic 200 MB Healthy (EFI System Partition) "Backup" 930.66 GB NTFS, Healthy (Primary Partition) What's a bit odd is that in Disk Management the "Backup" volume does not show a drive letter, even though I assigned Z: (which is reflected in "My Computer". I also cannot make this a dynamic disk as it says it's unsupported by the device.

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  • Partition problem tyring to install window 7 starter

    - by ant2009
    Hello HP Mini 210 I am trying to install windows starter 7. Currently I have installed fedora 14 xfce. And I have allocated 24 GB NTFS for hard disk for the windows partition. My current partitions are as follows: /dev/sda2 97G 4.9G 91G 6% / tmpfs 494M 92K 494M 1% /dev/shm /dev/sda1 485M 68M 392M 15% /boot /dev/sda5 169G 26G 135G 16% /home I have created a boot USD to install windows starter 7. When the computer boots into the windows setup and I selected the partition I want to install windows on. I get the following message: "Setup was unable to create a new system partition or locate an existing system partition." This is setup displaying all my partitions: Disk 0 Partition 1 500MB 0 Primary Disk 0 Partition 2 97.7GB 0 Primary Disk 0 Partition 3 4GB 0 Primary Disk 0 Partition 4 171.3GB 0 Logical Disk 0 Partition 5 24.6GB 24.5 Logical <-- Trying install on this partition NTFS I have also tried to delete the partition in setup and create a new one. And also tried to format the partition. However, I still get the same error message. Many thanks for any advice,

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  • Can't mount hard drive. Ubuntu 12.04

    - by Sam
    I am trying to recover some pictures on my 320 GB Hard Disk, so I put in a Live Ubuntu CD and am in that right now. In the devices list, it shows my USB drive, but not my 320 GB Hard Disk. I can see the disk in Disk Utility (it says it's on /dev/sda), but it's not mounted, and it says it has a few bad sectors but it is OK. In Disk Usage Analyzer, it says my maximum capacity is 13.4 GB, so it's definitely not using the 320 GB Hard Disk. I tried the following: sudo mkdir /media/newhd (worked) sudo mount /dev/sda /media/newhd (didn't work. it says I must specify the filesystem type) I then tried: fsck.ext4 -f /dev/sda (didn't work. Said: Superblock invalid, trying to backup blocks. then: Bad magic number in super-block while trying to open /dev/sda. The superblock could not be read or does not describe a correct ext2 filesystem. If the device is valid and it contains an ext2 filesystem (and not swap or ufs or something else), then the superblock is corrupt, and you might try running e2fsck with an alternate superblock) Does anyone have any ideas? The whole problem started when my Windows Vista said "Can't find operating system". Any ideas on how I can get on to my hard drive at /dev/sda?

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  • Shrinking windows and recovery partitions on the samsung new series 9

    - by bobbaluba
    I just bought a samsung NP900X3C, and as I was going to install linux, I noticed the windows partitions and recovery partitions occupied a major portion of the disk. The disk is a 128 GB SSD, and I want to keep the windows partition in order to play some games once in a while, but the windows disk is already 45GB full (with no installed programs) and the recovery partition is 20GB. That leaves under 60 GB for linux, which is not optimal, since that is what I'm going to be using most of the time, and there would be no room for games on the windows partition. There are also two small partitions that I don't know what are doing, one 100mb at the start of the disk that I'm guessing is some kind of boot partition, and one 5GB, that is described as an OS/2 hidden C: drive What I'm wondering is: can i delete the recovery partition? What about the mystical 5gb partition? Here is what fdisk reports: ubuntu@ubuntu:~$ sudo fdisk -l Disk /dev/sda: 128.0 GB, 128035676160 bytes 255 heads, 63 sectors/track, 15566 cylinders, total 250069680 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x83953ffc Device Boot Start End Blocks Id System /dev/sda1 * 2048 206847 102400 7 HPFS/NTFS/exFAT /dev/sda2 206848 198273023 99033088 7 HPFS/NTFS/exFAT /dev/sda3 198273024 207276031 4501504 84 OS/2 hidden C: drive /dev/sda4 207276032 250068991 21396480 27 Hidden NTFS WinRE

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  • SBS 2008 Backup Drive Full - Error Code '2147942512'

    - by HK1
    We are using Windows Backup on SBS 2008 SP2 and backing up to 1TB external hard drives. Recently after switching drives our backup started failing because the backup drive is full and auto-delete isn't automatically deleting older backups/show copies. I'm trying to get more information to help me effectively prevent this problem from reoccurring in the future. How I can tell that the drive is getting full: In the event viewer under Windows Logs Application, I'm seeing Event ID 517 but it fails to show an intelligible description. However, under Applications and Services Logs Microsoft Windows Backup Operational, I'm seeing an event with the ID of 5 and a description like this: Backup started at '10/4/2011 12:30:12 PM' failed with following error code '2147942512'. One of the most informative posts I've found on this error is located on Microsoft's Technet Forums here. In that post, a Microsoft representative gives this hazy explanation: auto-delete feature to ensure that at least some old backup copies are maintained on the disk -- does not automatically delete backups if space utilization by older copies is less than 1/8 of the disk size or in other words, 13% of the disk size. that means if the one full backup copy does not fit in the 7/8 of the disk size, backup may fail with disk full error. auto-delete will not automatically delete older versions to reclaim more older versions of backup. In the above explanation, I do not understand what is meant by "older copies" except that it appears that anything older than the very last shadow copy would be considered "older copies". I'm going to make the assumption that this problem where auto-delete will not work will affect any hard drive that is large enough to make an effective backup drive, or in other words, any hard drive that is large enough to hold more than one backup/shadow copy at once. The same MS representative proposes the solution of using a larger backup drive. I can't understand how this will help. It appears to me it will simply delay the problem until a later date. In order to resolve this problem for now, I did the following: Assign the backup drive a disk letter under disk management. Run the command line with Administrative rights. diskshadow.exe [enter] delete shadows oldest x: [enter] (where X: is the letter you assigned your backup drive) I manually ran the above command some 60 or 80 times to free up about 200 GB of space on my 1 Terrabyte External Hard drive. However, I do not feel this is a satisfactory solution to prevent the problem from happening again in the future. Does anyone have a solution to prevent your Windows Server backup drive from getting full?

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  • Interrupt ?13 (ah=48) - don't working

    - by GLeBaTi
    mov dl,00h mov ah,08h int 13h this is code showing normal parameters of floppy disk. mov dl,80h mov ah,08h int 13h this is code, showing not valid parameters of hard disk(may be, my hard disk space is big (LBA)), And I've written this code: mov dl,80h mov ah,48h int 13h it is code doing cf = 1(error). How fix it? I want learn parameters of my hard disk. (http://lrs.uni-passau.de/support/doc/interrupt-57/RB-0677.HTM)

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  • How to reliably map vSphere disks <-> Linux devices

    - by brianmcgee
    Task at hand After a virtual disk has been added to a Linux VM on vSphere 5, we need to identify the disks in order to automate the LVM storage provision. The virtual disks may reside on different datastores (e.g. sas or flash) and although they may be of the same size, their speed may vary. So I need a method to map the vSphere disks to Linux devices. Ideas Through the vSphere API, I am able to get the device info: Data Object Type: VirtualDiskFlatVer2BackingInfo Parent Managed Object ID: vm-230 Property Path: config.hardware.device[2000].backing Properties Name Type Value ChangeId string Unset contentId string "d58ec8c12486ea55c6f6d913642e1801" datastore ManagedObjectReference:Datastore datastore-216 (W5-CFAS012-Hybrid-CL20-004) deltaDiskFormat string "redoLogFormat" deltaGrainSize int Unset digestEnabled boolean false diskMode string "persistent" dynamicProperty DynamicProperty[] Unset dynamicType string Unset eagerlyScrub boolean Unset fileName string "[W5-CFAS012-Hybrid-CL20-004] l****9-000001.vmdk" parent VirtualDiskFlatVer2BackingInfo parent split boolean false thinProvisioned boolean false uuid string "6000C295-ab45-704e-9497-b25d2ba8dc00" writeThrough boolean false And on Linux I may read the uuid strings: [root@lx***** ~]# lsscsi -t [1:0:0:0] cd/dvd ata: /dev/sr0 [2:0:0:0] disk sas:0x5000c295ab45704e /dev/sda [3:0:0:0] disk sas:0x5000c2932dfa693f /dev/sdb [3:0:1:0] disk sas:0x5000c29dcd64314a /dev/sdc As you can see, the uuid string of disk /dev/sda looks somehow familiar to the string that is visible in the VMware API. Only the first hex digit is different (5 vs. 6) and it is only present to the third hyphen. So this looks promising... Alternative idea Select disks by controller. But is it reliable that the ascending SCSI Id also matches the next vSphere virtual disk? What happens if I add another DVD-ROM drive / USB Thumb drive? This will probably introduce new SCSI devices in between. Thats the cause why I think I will discard this idea. Questions Does someone know an easier method to map vSphere disks and Linux devices? Can someone explain the differences in the uuid strings? (I think this has something to do with SAS adressing initiator and target... WWN like...) May I reliably map devices by using those uuid strings? How about SCSI virtual disks? There is no uuid visible then... This task seems to be so obvious. Why doesn't Vmware think about this and simply add a way to query the disk mapping via Vmware Tools?

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  • Interrupt ?13 (ah=48) - not working

    - by GLeBaTi
    I want fetch the parameters of my hard disk. Using the technique described here. This is code showing normal parameters of floppy disk: mov dl,00h mov ah,08h int 13h This is code, showing not valid parameters of hard disk (may be, my hard disk space is big (LBA)): mov dl,80h mov ah,08h int 13h And I've written this code: mov dl,80h mov ah,48h int 13h The code is giving cf = 1(error). How do I fix it?

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  • Windows 2008 Unknown Disks

    - by Ailbe
    I have a BL460c G7 blade server with OS Windows 2008 R2 SP1. This is a brand new C7000 enclosure, with FlexFabric interconnects. I got my FC switches setup and zoned properly to our Clariion CX4, and can see all the hosts that are assigned FCoE HBAs on both paths in both Navisphere and in HP Virtual Connect Manager. So I went ahead and created a storage group for a test server, assigned the appropriate host, assigned the LUN to the server. So far so good, log onto server and I can see 4 unknown disks.... No problem, I install MS MPIO, no luck, can't initialize the disks, and the multiple disks don't go away. Still no problem, I install PowerPath version 5.5 reboot. Now I see 3 disks. One is initialized and ready to go, but I still have 2 disks that I can't initialize, can't offline, can't delete. If I right click in storage manager and go to properties I can see that the MS MPIO tab, but I can't make a path active. I want to get rid of these phantom disks, but so far nothing is working and google searches are showing up some odd results, so obviously I'm not framing my question right. I thought I'd ask here real quick. Does anyone know a quick way to get rid of these unknown disks. Another question, do I need the MPIO feature installed if I have PowerPath installed? This is my first time installing Windows 2008 R2 in this fashion and I'm not sure if that feature is needed or not right now. So some more information to add to this. It seems I'm dealing with more of a Windows issue than anything else. I removed the LUN from the server, uninstalled PowerPath completely, removed the MPIO feature from the server, and rebooted twice. Now I am back to the original 4 Unknown Disks (plus the local Disk 0 containing the OS partition of course, which is working fine) I went to diskpart, I could see all 4 Unknown disks, I selected each disk, ran clean (just in case i'd somehow brought them online previously as GPT and didn't realize it) After a few minutes I was no longer able to see the disks when I ran list disk. However, the disks are still in Disk Management. When I try and offline the disks from Disk Management I get an error: Virtual Disk Manager - The system cannot find the file specified. Accompanied by an error in System Event Logs: Log Name: System Source: Virtual Disk Service Date: 6/25/2012 4:02:01 PM Event ID: 1 Task Category: None Level: Error Keywords: Classic User: N/A Computer: hostname.local Description: Unexpected failure. Error code: 2@02000018 Event Xml: 1 2 0 0x80000000000000 4239 System hostname.local 2@02000018 I feel sure there is a place I can go in the Registry to get rid of these, I just can't recall where and I am loathe to experiement. So to recap, there are currently no LUNS attached at all, I still have the phantom disks, and I'm getting The system cannot find the file specified from Virtual Disk Manager when I try to take them offline. Thanks!

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  • Kernel panic when bringing up DRBD resource

    - by sc.
    I'm trying to set up two machines synchonizing with DRBD. The storage is setup as follows: PV - LVM - DRBD - CLVM - GFS2. DRBD is set up in dual primary mode. The first server is set up and running fine in primary mode. The drives on the first server have data on them. I've set up the second server and I'm trying to bring up the DRBD resources. I created all the base LVM's to match the first server. After initializing the resources with `` drbdadm create-md storage I'm bringing up the resources by issuing drbdadm up storage After issuing that command, I get a kernel panic and the server reboots in 30 seconds. Here's a screen capture. My configuration is as follows: OS: CentOS 6 uname -a Linux host.structuralcomponents.net 2.6.32-279.5.2.el6.x86_64 #1 SMP Fri Aug 24 01:07:11 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux rpm -qa | grep drbd kmod-drbd84-8.4.1-2.el6.elrepo.x86_64 drbd84-utils-8.4.1-2.el6.elrepo.x86_64 cat /etc/drbd.d/global_common.conf global { usage-count yes; # minor-count dialog-refresh disable-ip-verification } common { handlers { pri-on-incon-degr "/usr/lib/drbd/notify-pri-on-incon-degr.sh; /usr/lib/drbd/notify-emergency-reboot.sh; echo b /proc/sysrq-trigger ; reboot -f"; pri-lost-after-sb "/usr/lib/drbd/notify-pri-lost-after-sb.sh; /usr/lib/drbd/notify-emergency-reboot.sh; echo b /proc/sysrq-trigger ; reboot -f"; local-io-error "/usr/lib/drbd/notify-io-error.sh; /usr/lib/drbd/notify-emergency-shutdown.sh; echo o /proc/sysrq-trigger ; halt -f"; # fence-peer "/usr/lib/drbd/crm-fence-peer.sh"; # split-brain "/usr/lib/drbd/notify-split-brain.sh root"; # out-of-sync "/usr/lib/drbd/notify-out-of-sync.sh root"; # before-resync-target "/usr/lib/drbd/snapshot-resync-target-lvm.sh -p 15 -- -c 16k"; # after-resync-target /usr/lib/drbd/unsnapshot-resync-target-lvm.sh; } startup { # wfc-timeout degr-wfc-timeout outdated-wfc-timeout wait-after-sb become-primary-on both; wfc-timeout 30; degr-wfc-timeout 10; outdated-wfc-timeout 10; } options { # cpu-mask on-no-data-accessible } disk { # size max-bio-bvecs on-io-error fencing disk-barrier disk-flushes # disk-drain md-flushes resync-rate resync-after al-extents # c-plan-ahead c-delay-target c-fill-target c-max-rate # c-min-rate disk-timeout } net { # protocol timeout max-epoch-size max-buffers unplug-watermark # connect-int ping-int sndbuf-size rcvbuf-size ko-count # allow-two-primaries cram-hmac-alg shared-secret after-sb-0pri # after-sb-1pri after-sb-2pri always-asbp rr-conflict # ping-timeout data-integrity-alg tcp-cork on-congestion # congestion-fill congestion-extents csums-alg verify-alg # use-rle protocol C; allow-two-primaries yes; after-sb-0pri discard-zero-changes; after-sb-1pri discard-secondary; after-sb-2pri disconnect; } } cat /etc/drbd.d/storage.res resource storage { device /dev/drbd0; meta-disk internal; on host.structuralcomponents.net { address 10.10.1.120:7788; disk /dev/vg_storage/lv_storage; } on host2.structuralcomponents.net { address 10.10.1.121:7788; disk /dev/vg_storage/lv_storage; } /var/log/messages is not logging anything about the crash. I've been trying to find a cause of this but I've come up with nothing. Can anyone help me out? Thanks.

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  • Grub 'Read Error' - Only Loads with LiveCD

    - by Ryan Sharp
    Problem After installing Ubuntu to complete my Windows 7/Ubuntu 12.04 dual-boot setup, Grub just wouldn't load at all unless I boot from the LiveCD. Afterwards, everything works completely normal. However, this workaround isn't a solution and I'd like to be able to boot without the aid of a disc. Fdisk -l Using the fdisk -l command, I am given the following: Disk /dev/sda: 64.0 GB, 64023257088 bytes 255 heads, 63 sectors/track, 7783 cylinders, total 125045424 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x324971d1 Device Boot Start End Blocks Id System /dev/sda1 2048 206847 102400 7 HPFS/NTFS/exFAT /dev/sda2 208896 48957439 24374272 7 HPFS/NTFS/exFAT /dev/sda3 * 48959486 124067839 37554177 5 Extended /dev/sda5 48959488 124067839 37554176 83 Linux Disk /dev/sdb: 1000.2 GB, 1000204886016 bytes 255 heads, 63 sectors/track, 121601 cylinders, total 1953525168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0xc0ee6a69 Device Boot Start End Blocks Id System /dev/sdb1 1024208894 1953523711 464657409 5 Extended /dev/sdb3 * 2048 1024206847 512102400 7 HPFS/NTFS/exFAT /dev/sdb5 1024208896 1937897471 456844288 83 Linux /dev/sdb6 1937899520 1953523711 7812096 82 Linux swap / Solaris Partition table entries are not in disk order Disk /dev/sdc: 320.1 GB, 320072933376 bytes 255 heads, 63 sectors/track, 38913 cylinders, total 625142448 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x292eee23 Device Boot Start End Blocks Id System /dev/sdc1 2048 625141759 312569856 7 HPFS/NTFS/exFAT Bootinfoscript I've used the BootInfoScript, and received the following output: Boot Info Script 0.61 [1 April 2012] ============================= Boot Info Summary: =============================== => Grub2 (v1.99) is installed in the MBR of /dev/sda and looks at sector 1 of the same hard drive for core.img. core.img is at this location and looks for (,msdos5)/boot/grub on this drive. => Grub2 (v1.99) is installed in the MBR of /dev/sdb and looks at sector 1 of the same hard drive for core.img. core.img is at this location and looks for (,msdos5)/boot/grub on this drive. => Windows is installed in the MBR of /dev/sdc. sda1: __________________________________________________________________________ File system: ntfs Boot sector type: Windows Vista/7: NTFS Boot sector info: No errors found in the Boot Parameter Block. Operating System: Boot files: /bootmgr /Boot/BCD sda2: __________________________________________________________________________ File system: ntfs Boot sector type: Windows Vista/7: NTFS Boot sector info: No errors found in the Boot Parameter Block. Operating System: Windows 7 Boot files: /bootmgr /Boot/BCD /Windows/System32/winload.exe sda3: __________________________________________________________________________ File system: Extended Partition Boot sector type: Unknown Boot sector info: sda5: __________________________________________________________________________ File system: ext4 Boot sector type: - Boot sector info: Operating System: Ubuntu 12.04.1 LTS Boot files: /boot/grub/grub.cfg /etc/fstab /boot/grub/core.img sdb1: __________________________________________________________________________ File system: Extended Partition Boot sector type: - Boot sector info: sdb5: __________________________________________________________________________ File system: ext4 Boot sector type: - Boot sector info: Operating System: Boot files: sdb6: __________________________________________________________________________ File system: swap Boot sector type: - Boot sector info: sdb3: __________________________________________________________________________ File system: ntfs Boot sector type: Windows Vista/7: NTFS Boot sector info: According to the info in the boot sector, sdb3 starts at sector 200744960. But according to the info from fdisk, sdb3 starts at sector 2048. According to the info in the boot sector, sdb3 has 823461887 sectors, but according to the info from fdisk, it has 1024204799 sectors. Operating System: Boot files: sdc1: __________________________________________________________________________ File system: ntfs Boot sector type: Windows Vista/7: NTFS Boot sector info: No errors found in the Boot Parameter Block. Operating System: Boot files: ============================ Drive/Partition Info: ============================= Drive: sda _____________________________________________________________________ Disk /dev/sda: 64.0 GB, 64023257088 bytes 255 heads, 63 sectors/track, 7783 cylinders, total 125045424 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes Partition Boot Start Sector End Sector # of Sectors Id System /dev/sda1 2,048 206,847 204,800 7 NTFS / exFAT / HPFS /dev/sda2 208,896 48,957,439 48,748,544 7 NTFS / exFAT / HPFS /dev/sda3 * 48,959,486 124,067,839 75,108,354 5 Extended /dev/sda5 48,959,488 124,067,839 75,108,352 83 Linux Drive: sdb _____________________________________________________________________ Disk /dev/sdb: 1000.2 GB, 1000204886016 bytes 255 heads, 63 sectors/track, 121601 cylinders, total 1953525168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes Partition Boot Start Sector End Sector # of Sectors Id System /dev/sdb1 1,024,208,894 1,953,523,711 929,314,818 5 Extended /dev/sdb5 1,024,208,896 1,937,897,471 913,688,576 83 Linux /dev/sdb6 1,937,899,520 1,953,523,711 15,624,192 82 Linux swap / Solaris /dev/sdb3 * 2,048 1,024,206,847 1,024,204,800 7 NTFS / exFAT / HPFS Drive: sdc _____________________________________________________________________ Disk /dev/sdc: 320.1 GB, 320072933376 bytes 255 heads, 63 sectors/track, 38913 cylinders, total 625142448 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes Partition Boot Start Sector End Sector # of Sectors Id System /dev/sdc1 2,048 625,141,759 625,139,712 7 NTFS / exFAT / HPFS "blkid" output: ________________________________________________________________ Device UUID TYPE LABEL /dev/sda1 A48056DF8056B80E ntfs System Reserved /dev/sda2 A8C6D6A4C6D671D4 ntfs Windows /dev/sda5 fd71c537-3715-44e1-b1fe-07537e22b3dd ext4 /dev/sdb3 6373D03D0A3747A8 ntfs Steam /dev/sdb5 6f5a6eb3-a932-45aa-893e-045b57708270 ext4 /dev/sdb6 469848c8-867a-41b7-b0e1-b813a43c64af swap /dev/sdc1 725D7B961CF34B1B ntfs backup ================================ Mount points: ================================= Device Mount_Point Type Options /dev/sda5 / ext4 (rw,noatime,nodiratime,discard,errors=remount-ro) /dev/sdb5 /home ext4 (rw) =========================== sda5/boot/grub/grub.cfg: =========================== -------------------------------------------------------------------------------- # # DO NOT EDIT THIS FILE # # It is automatically generated by grub-mkconfig using templates # from /etc/grub.d and settings from /etc/default/grub # ### BEGIN /etc/grub.d/00_header ### if [ -s $prefix/grubenv ]; then set have_grubenv=true load_env fi set default="0" if [ "${prev_saved_entry}" ]; then set saved_entry="${prev_saved_entry}" save_env saved_entry set prev_saved_entry= save_env prev_saved_entry set boot_once=true fi function savedefault { if [ -z "${boot_once}" ]; then saved_entry="${chosen}" save_env saved_entry fi } function recordfail { set recordfail=1 if [ -n "${have_grubenv}" ]; then if [ -z "${boot_once}" ]; then save_env recordfail; fi; fi } function load_video { insmod vbe insmod vga insmod video_bochs insmod video_cirrus } insmod part_msdos insmod ext2 set root='(hd0,msdos5)' search --no-floppy --fs-uuid --set=root fd71c537-3715-44e1-b1fe-07537e22b3dd if loadfont /usr/share/grub/unicode.pf2 ; then set gfxmode=auto load_video insmod gfxterm insmod part_msdos insmod ext2 set root='(hd0,msdos5)' search --no-floppy --fs-uuid --set=root fd71c537-3715-44e1-b1fe-07537e22b3dd set locale_dir=($root)/boot/grub/locale set lang=en_GB insmod gettext fi terminal_output gfxterm if [ "${recordfail}" = 1 ]; then set timeout=-1 else set timeout=10 fi ### END /etc/grub.d/00_header ### ### BEGIN /etc/grub.d/05_debian_theme ### set menu_color_normal=white/black set menu_color_highlight=black/light-gray if background_color 44,0,30; then clear fi ### END /etc/grub.d/05_debian_theme ### ### BEGIN /etc/grub.d/10_linux ### function gfxmode { set gfxpayload="${1}" if [ "${1}" = "keep" ]; then set vt_handoff=vt.handoff=7 else set vt_handoff= fi } if [ "${recordfail}" != 1 ]; then if [ -e ${prefix}/gfxblacklist.txt ]; then if hwmatch ${prefix}/gfxblacklist.txt 3; then if [ ${match} = 0 ]; then set linux_gfx_mode=keep else set linux_gfx_mode=text fi else set linux_gfx_mode=text fi else set linux_gfx_mode=keep fi else set linux_gfx_mode=text fi export linux_gfx_mode if [ "${linux_gfx_mode}" != "text" ]; then load_video; fi menuentry 'Ubuntu, with Linux 3.2.0-29-generic' --class ubuntu --class gnu-linux --class gnu --class os { recordfail gfxmode $linux_gfx_mode insmod gzio insmod part_msdos insmod ext2 set root='(hd0,msdos5)' search --no-floppy --fs-uuid --set=root fd71c537-3715-44e1-b1fe-07537e22b3dd linux /boot/vmlinuz-3.2.0-29-generic root=UUID=fd71c537-3715-44e1-b1fe-07537e22b3dd ro quiet splash $vt_handoff initrd /boot/initrd.img-3.2.0-29-generic } menuentry 'Ubuntu, with Linux 3.2.0-29-generic (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os { recordfail insmod gzio insmod part_msdos insmod ext2 set root='(hd0,msdos5)' search --no-floppy --fs-uuid --set=root fd71c537-3715-44e1-b1fe-07537e22b3dd echo 'Loading Linux 3.2.0-29-generic ...' linux /boot/vmlinuz-3.2.0-29-generic root=UUID=fd71c537-3715-44e1-b1fe-07537e22b3dd ro recovery nomodeset echo 'Loading initial ramdisk ...' initrd /boot/initrd.img-3.2.0-29-generic } ### END /etc/grub.d/10_linux ### ### BEGIN /etc/grub.d/20_linux_xen ### ### END /etc/grub.d/20_linux_xen ### ### BEGIN /etc/grub.d/20_memtest86+ ### menuentry "Memory test (memtest86+)" { insmod part_msdos insmod ext2 set root='(hd0,msdos5)' search --no-floppy --fs-uuid --set=root fd71c537-3715-44e1-b1fe-07537e22b3dd linux16 /boot/memtest86+.bin } menuentry "Memory test (memtest86+, serial console 115200)" { insmod part_msdos insmod ext2 set root='(hd0,msdos5)' search --no-floppy --fs-uuid --set=root fd71c537-3715-44e1-b1fe-07537e22b3dd linux16 /boot/memtest86+.bin console=ttyS0,115200n8 } ### END /etc/grub.d/20_memtest86+ ### ### BEGIN /etc/grub.d/30_os-prober ### menuentry "Windows 7 (loader) (on /dev/sda1)" --class windows --class os { insmod part_msdos insmod ntfs set root='(hd0,msdos1)' search --no-floppy --fs-uuid --set=root A48056DF8056B80E chainloader +1 } menuentry "Windows 7 (loader) (on /dev/sda2)" --class windows --class os { insmod part_msdos insmod ntfs set root='(hd0,msdos2)' search --no-floppy --fs-uuid --set=root A8C6D6A4C6D671D4 chainloader +1 } ### END /etc/grub.d/30_os-prober ### ### BEGIN /etc/grub.d/40_custom ### # This file provides an easy way to add custom menu entries. Simply type the # menu entries you want to add after this comment. Be careful not to change # the 'exec tail' line above. ### END /etc/grub.d/40_custom ### ### BEGIN /etc/grub.d/41_custom ### if [ -f $prefix/custom.cfg ]; then source $prefix/custom.cfg; fi ### END /etc/grub.d/41_custom ### -------------------------------------------------------------------------------- =============================== sda5/etc/fstab: ================================ -------------------------------------------------------------------------------- # /etc/fstab: static file system information. # # Use 'blkid' to print the universally unique identifier for a # device; this may be used with UUID= as a more robust way to name devices # that works even if disks are added and removed. See fstab(5). # # <file system> <mount point> <type> <options> <dump> <pass> proc /proc proc nodev,noexec,nosuid 0 0 # / was on /dev/sda5 during installation UUID=fd71c537-3715-44e1-b1fe-07537e22b3dd / ext4 noatime,nodiratime,discard,errors=remount-ro 0 1 # /home was on /dev/sdb5 during installation UUID=6f5a6eb3-a932-45aa-893e-045b57708270 /home ext4 defaults 0 2 # swap was on /dev/sdb6 during installation UUID=469848c8-867a-41b7-b0e1-b813a43c64af none swap sw 0 0 tmpfs /tmp tmpfs defaults,noatime,mode=1777 0 0 -------------------------------------------------------------------------------- =================== sda5: Location of files loaded by Grub: ==================== GiB - GB File Fragment(s) = boot/grub/core.img 1 = boot/grub/grub.cfg 1 = boot/initrd.img-3.2.0-29-generic 2 = boot/vmlinuz-3.2.0-29-generic 1 = initrd.img 2 = vmlinuz 1 ======================== Unknown MBRs/Boot Sectors/etc: ======================== Unknown BootLoader on sda3 00000000 63 6f 70 69 61 20 65 20 63 6f 6c 61 41 63 65 64 |copia e colaAced| 00000010 65 72 20 61 20 74 6f 64 6f 20 6f 20 74 65 78 74 |er a todo o text| 00000020 6f 20 66 61 6c 61 64 6f 20 75 74 69 6c 69 7a 61 |o falado utiliza| 00000030 6e 64 6f 20 61 20 63 6f 6e 76 65 72 73 c3 a3 6f |ndo a convers..o| 00000040 20 64 65 20 74 65 78 74 6f 20 70 61 72 61 20 76 | de texto para v| 00000050 6f 7a 4d 61 6e 69 70 75 6c 61 72 20 61 73 20 64 |ozManipular as d| 00000060 65 66 69 6e 69 c3 a7 c3 b5 65 73 20 71 75 65 20 |efini....es que | 00000070 63 6f 6e 74 72 6f 6c 61 6d 20 6f 20 61 63 65 73 |controlam o aces| 00000080 73 6f 20 64 65 20 57 65 62 73 69 74 65 73 20 61 |so de Websites a| 00000090 20 63 6f 6f 6b 69 65 73 2c 20 4a 61 76 61 53 63 | cookies, JavaSc| 000000a0 72 69 70 74 20 65 20 70 6c 75 67 2d 69 6e 73 4d |ript e plug-insM| 000000b0 61 6e 69 70 75 6c 61 72 20 61 73 20 64 65 66 69 |anipular as defi| 000000c0 6e 69 c3 a7 c3 b5 65 73 20 72 65 6c 61 63 69 6f |ni....es relacio| 000000d0 6e 61 64 61 73 20 63 6f 6d 20 70 72 69 76 61 63 |nadas com privac| 000000e0 69 64 61 64 65 41 63 65 64 65 72 20 61 6f 73 20 |idadeAceder aos | 000000f0 73 65 75 73 20 70 65 72 69 66 c3 a9 72 69 63 6f |seus perif..rico| 00000100 73 20 55 53 42 55 74 69 6c 69 7a 61 72 20 6f 20 |s USBUtilizar o | 00000110 73 65 75 20 6d 69 63 72 6f 66 6f 6e 65 55 74 69 |seu microfoneUti| 00000120 6c 69 7a 61 72 20 61 20 73 75 61 20 63 c3 a2 6d |lizar a sua c..m| 00000130 61 72 61 55 74 69 6c 69 7a 61 72 20 6f 20 73 65 |araUtilizar o se| 00000140 75 20 6d 69 63 72 6f 66 6f 6e 65 20 65 20 61 20 |u microfone e a | 00000150 63 c3 a2 6d 61 72 61 4e c3 a3 6f 20 66 6f 69 20 |c..maraN..o foi | 00000160 70 6f 73 73 c3 ad 76 65 6c 20 65 6e 63 6f 6e 74 |poss..vel encont| 00000170 72 61 72 20 6f 20 63 61 6d 69 6e 68 6f 20 61 62 |rar o caminho ab| 00000180 73 6f 6c 75 74 6f 20 70 61 72 61 20 6f 20 64 69 |soluto para o di| 00000190 72 65 63 74 c3 b3 72 69 6f 20 61 20 65 6d 70 61 |rect..rio a empa| 000001a0 63 6f 74 61 72 2e 4f 20 64 69 72 65 63 74 c3 b3 |cotar.O direct..| 000001b0 72 69 6f 20 64 65 20 65 6e 74 72 61 64 61 00 fe |rio de entrada..| 000001c0 ff ff 83 fe ff ff 02 00 00 00 00 10 7a 04 00 00 |............z...| 000001d0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| * 000001f0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 55 aa |..............U.| 00000200 =============================== StdErr Messages: =============================== xz: (stdin): Compressed data is corrupt xz: (stdin): Compressed data is corrupt awk: cmd. line:36: Math support is not compiled in awk: cmd. line:36: Math support is not compiled in awk: cmd. line:36: Math support is not compiled in awk: cmd. line:36: Math support is not compiled in awk: cmd. line:36: Math support is not compiled in awk: cmd. line:36: Math support is not compiled in Begging / Appreciation ;) If anything else is required to solve my problem, please ask. My only hopes are that I can solve this, and that doing so won't require re-installation of Grub due to how complicated the procedures are, or that I would be needed to reinstall the OS', as I have done so about six times already since friday due to several other issues I've encountered. Thank you, and good day. System Ubuntu 12.04 64-bit / Windows 7 SP1 64-bit 64GB SSD as boot/OS drive, 1TB HDD as /Home Swap and Steam drive.

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  • How to disable Mac OS X from using swap when there still is "Inactive" memory?

    - by Motin
    A common phenomena in my day to day usage (and several other's according to various posts throughout the internet) of OS X, the system seems to become slow whenever there is no more "Free" memory available. Supposedly, this is due to swapping, since heavy disk activity is apparent and that vm_stat reports many pageouts. (Correct me from wrong) However, the amount of "Inactive" ram is typically around 12.5%-25% of all available memory (^1.) when swapping starts/occurs/ends. According to http://support.apple.com/kb/ht1342 : Inactive memory This information in memory is not actively being used, but was recently used. For example, if you've been using Mail and then quit it, the RAM that Mail was using is marked as Inactive memory. This Inactive memory is available for use by another application, just like Free memory. However, if you open Mail before its Inactive memory is used by a different application, Mail will open quicker because its Inactive memory is converted to Active memory, instead of loading Mail from the slower hard disk. And according to http://developer.apple.com/library/mac/#documentation/Performance/Conceptual/ManagingMemory/Articles/AboutMemory.html : The inactive list contains pages that are currently resident in physical memory but have not been accessed recently. These pages contain valid data but may be released from memory at any time. So, basically: When a program has quit, it's memory becomes marked as Inactive and should be claimable at any time. Still, OS X will prefer to start swapping out memory to the Swap file instead of just claiming this memory, whenever the "Free" memory gets to low. Why? What is the advantage of this behavior over, say, instantly releasing Inactive memory and not even touch the swap file? Some sources (^2.) indicate that OS X would page out the "Inactive" memory to swap before releasing it, but that doesn't make sense now does it if the memory may be released from memory at any time? Swapping is expensive, releasing is cheap, right? Can this behavior be changed using some preference or known hack? (Preferably one that doesn't include disabling swap/dynamic_pager altogether and restarting...) I do appreciate the purge command, as well as the concept of Repairing disk permissions to force some Free memory, but those are ways to painfully force more Free memory than to actually fixing the swap/release decision logic... Btw a similar question was asked here: http://forums.macnn.com/90/mac-os-x/434650/why-does-os-x-swap-when/ and here: http://hintsforums.macworld.com/showthread.php?t=87688 but even though the OPs re-asked the core question, none of the replies addresses an answer to it... ^1. UPDATE 17-mar-2012 Since I first posted this question, I have gone from 4gb to 8gb of installed ram, and the problem remains. The amount of "Inactive" ram was 0.5gb-1.0gb before and is now typically around 1.0-2.0GB when swapping starts/occurs/ends, ie it seems that around 12.5%-25% of the ram is preserved as Inactive by osx kernel logic. ^2. For instance http://apple.stackexchange.com/questions/4288/what-does-it-mean-if-i-have-lots-of-inactive-memory-at-the-end-of-a-work-day : Once all your memory is used (free memory is 0), the OS will write out inactive memory to the swapfile to make more room in active memory. UPDATE 17-mar-2012 Here is a round-up of the methods that have been suggested to help so far: The purge command "Used to approximate initial boot conditions with a cold disk buffer cache for performance analysis. It does not affect anonymous memory that has been allocated through malloc, vm_allocate, etc". This is useful to prevent osx to swap-out the disk cache (which is ridiculous that osx actually does so in the first place), but with the downside that the disk cache is released, meaning that if the disk cache was not about to be swapped out, one would simply end up with a cold disk buffer cache, probably affecting performance negatively. The FreeMemory app and/or Repairing disk permissions to force some Free memory Doesn't help releasing any memory, only moving some gigabytes of memory contents from ram to the hd. In the end, this causes lots of swap-ins when I attempt to use the applications that were open while freeing memory, as a lot of its vm is now on swap. Speeding up swap-allocation using dynamicpagerwrapper Seems a good thing to do in order to speed up swap-usage, but does not address the problem of osx swapping in the first place while there is still inactive memory. Disabling swap by disabling dynamicpager and restarting This will force osx not to use swap to the price of the system hanging when all memory is used. Not a viable alternative... Disabling swap using a hacked dynamicpager Similar to disabling dynamicpager above, some excerpts from the comments to the blog post indicate that this is not a viable solution: "The Inactive Memory is high as usual". "when your system is running out of memory, the whole os hangs...", "if you consume the whole amount of memory of the mac, the machine will likely hang" To sum up, I am still unaware of a way of disabling Mac OS X from using swap when there still is "Inactive" memory. If it isn't possible, maybe at least there is an explanation somewhere of why osx prefers to swap out memory that may be released from memory at any time?

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  • What's up with LDoms: Part 1 - Introduction & Basic Concepts

    - by Stefan Hinker
    LDoms - the correct name is Oracle VM Server for SPARC - have been around for quite a while now.  But to my surprise, I get more and more requests to explain how they work or to give advise on how to make good use of them.  This made me think that writing up a few articles discussing the different features would be a good idea.  Now - I don't intend to rewrite the LDoms Admin Guide or to copy and reformat the (hopefully) well known "Beginners Guide to LDoms" by Tony Shoumack from 2007.  Those documents are very recommendable - especially the Beginners Guide, although based on LDoms 1.0, is still a good place to begin with.  However, LDoms have come a long way since then, and I hope to contribute to their adoption by discussing how they work and what features there are today.  In this and the following posts, I will use the term "LDoms" as a common abbreviation for Oracle VM Server for SPARC, just because it's a lot shorter and easier to type (and presumably, read). So, just to get everyone on the same baseline, lets briefly discuss the basic concepts of virtualization with LDoms.  LDoms make use of a hypervisor as a layer of abstraction between real, physical hardware and virtual hardware.  This virtual hardware is then used to create a number of guest systems which each behave very similar to a system running on bare metal:  Each has its own OBP, each will install its own copy of the Solaris OS and each will see a certain amount of CPU, memory, disk and network resources available to it.  Unlike some other type 1 hypervisors running on x86 hardware, the SPARC hypervisor is embedded in the system firmware and makes use both of supporting functions in the sun4v SPARC instruction set as well as the overall CPU architecture to fulfill its function. The CMT architecture of the supporting CPUs (T1 through T4) provide a large number of cores and threads to the OS.  For example, the current T4 CPU has eight cores, each running 8 threads, for a total of 64 threads per socket.  To the OS, this looks like 64 CPUs.  The SPARC hypervisor, when creating guest systems, simply assigns a certain number of these threads exclusively to one guest, thus avoiding the overhead of having to schedule OS threads to CPUs, as do typical x86 hypervisors.  The hypervisor only assigns CPUs and then steps aside.  It is not involved in the actual work being dispatched from the OS to the CPU, all it does is maintain isolation between different guests. Likewise, memory is assigned exclusively to individual guests.  Here,  the hypervisor provides generic mappings between the physical hardware addresses and the guest's views on memory.  Again, the hypervisor is not involved in the actual memory access, it only maintains isolation between guests. During the inital setup of a system with LDoms, you start with one special domain, called the Control Domain.  Initially, this domain owns all the hardware available in the system, including all CPUs, all RAM and all IO resources.  If you'd be running the system un-virtualized, this would be what you'd be working with.  To allow for guests, you first resize this initial domain (also called a primary domain in LDoms speak), assigning it a small amount of CPU and memory.  This frees up most of the available CPU and memory resources for guest domains.  IO is a little more complex, but very straightforward.  When LDoms 1.0 first came out, the only way to provide IO to guest systems was to create virtual disk and network services and attach guests to these services.  In the meantime, several different ways to connect guest domains to IO have been developed, the most recent one being SR-IOV support for network devices released in version 2.2 of Oracle VM Server for SPARC. I will cover these more advanced features in detail later.  For now, lets have a short look at the initial way IO was virtualized in LDoms: For virtualized IO, you create two services, one "Virtual Disk Service" or vds, and one "Virtual Switch" or vswitch.  You can, of course, also create more of these, but that's more advanced than I want to cover in this introduction.  These IO services now connect real, physical IO resources like a disk LUN or a networt port to the virtual devices that are assigned to guest domains.  For disk IO, the normal case would be to connect a physical LUN (or some other storage option that I'll discuss later) to one specific guest.  That guest would be assigned a virtual disk, which would appear to be just like a real LUN to the guest, while the IO is actually routed through the virtual disk service down to the physical device.  For network, the vswitch acts very much like a real, physical ethernet switch - you connect one physical port to it for outside connectivity and define one or more connections per guest, just like you would plug cables between a real switch and a real system. For completeness, there is another service that provides console access to guest domains which mimics the behavior of serial terminal servers. The connections between the virtual devices on the guest's side and the virtual IO services in the primary domain are created by the hypervisor.  It uses so called "Logical Domain Channels" or LDCs to create point-to-point connections between all of these devices and services.  These LDCs work very similar to high speed serial connections and are configured automatically whenever the Control Domain adds or removes virtual IO. To see all this in action, now lets look at a first example.  I will start with a newly installed machine and configure the control domain so that it's ready to create guest systems. In a first step, after we've installed the software, let's start the virtual console service and downsize the primary domain.  root@sun # ldm list NAME STATE FLAGS CONS VCPU MEMORY UTIL UPTIME primary active -n-c-- UART 512 261632M 0.3% 2d 13h 58m root@sun # ldm add-vconscon port-range=5000-5100 \ primary-console primary root@sun # svcadm enable vntsd root@sun # svcs vntsd STATE STIME FMRI online 9:53:21 svc:/ldoms/vntsd:default root@sun # ldm set-vcpu 16 primary root@sun # ldm set-mau 1 primary root@sun # ldm start-reconf primary root@sun # ldm set-memory 7680m primary root@sun # ldm add-config initial root@sun # shutdown -y -g0 -i6 So what have I done: I've defined a range of ports (5000-5100) for the virtual network terminal service and then started that service.  The vnts will later provide console connections to guest systems, very much like serial NTS's do in the physical world. Next, I assigned 16 vCPUs (on this platform, a T3-4, that's two cores) to the primary domain, freeing the rest up for future guest systems.  I also assigned one MAU to this domain.  A MAU is a crypto unit in the T3 CPU.  These need to be explicitly assigned to domains, just like CPU or memory.  (This is no longer the case with T4 systems, where crypto is always available everywhere.) Before I reassigned the memory, I started what's called a "delayed reconfiguration" session.  That avoids actually doing the change right away, which would take a considerable amount of time in this case.  Instead, I'll need to reboot once I'm all done.  I've assigned 7680MB of RAM to the primary.  That's 8GB less the 512MB which the hypervisor uses for it's own private purposes.  You can, depending on your needs, work with less.  I'll spend a dedicated article on sizing, discussing the pros and cons in detail. Finally, just before the reboot, I saved my work on the ILOM, to make this configuration available after a powercycle of the box.  (It'll always be available after a simple reboot, but the ILOM needs to know the configuration of the hypervisor after a power-cycle, before the primary domain is booted.) Now, lets create a first disk service and a first virtual switch which is connected to the physical network device igb2. We will later use these to connect virtual disks and virtual network ports of our guest systems to real world storage and network. root@sun # ldm add-vds primary-vds root@sun # ldm add-vswitch net-dev=igb2 switch-primary primary You are free to choose whatever names you like for the virtual disk service and the virtual switch.  I strongly recommend that you choose names that make sense to you and describe the function of each service in the context of your implementation.  For the vswitch, for example, you could choose names like "admin-vswitch" or "production-network" etc. This already concludes the configuration of the control domain.  We've freed up considerable amounts of CPU and RAM for guest systems and created the necessary infrastructure - console, vts and vswitch - so that guests systems can actually interact with the outside world.  The system is now ready to create guests, which I'll describe in the next section. For further reading, here are some recommendable links: The LDoms 2.2 Admin Guide The "Beginners Guide to LDoms" The LDoms Information Center on MOS LDoms on OTN

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  • Commit in SQL

    - by PRajkumar
    SQL Transaction Control Language Commands (TCL)                                           (COMMIT) Commit Transaction As a SQL language we use transaction control language very frequently. Committing a transaction means making permanent the changes performed by the SQL statements within the transaction. A transaction is a sequence of SQL statements that Oracle Database treats as a single unit. This statement also erases all save points in the transaction and releases transaction locks. Oracle Database issues an implicit COMMIT before and after any data definition language (DDL) statement. Oracle recommends that you explicitly end every transaction in your application programs with a COMMIT or ROLLBACK statement, including the last transaction, before disconnecting from Oracle Database. If you do not explicitly commit the transaction and the program terminates abnormally, then the last uncommitted transaction is automatically rolled back.   Until you commit a transaction: ·         You can see any changes you have made during the transaction by querying the modified tables, but other users cannot see the changes. After you commit the transaction, the changes are visible to other users' statements that execute after the commit ·         You can roll back (undo) any changes made during the transaction with the ROLLBACK statement   Note: Most of the people think that when we type commit data or changes of what you have made has been written to data files, but this is wrong when you type commit it means that you are saying that your job has been completed and respective verification will be done by oracle engine that means it checks whether your transaction achieved consistency when it finds ok it sends a commit message to the user from log buffer but not from data buffer, so after writing data in log buffer it insists data buffer to write data in to data files, this is how it works.   Before a transaction that modifies data is committed, the following has occurred: ·         Oracle has generated undo information. The undo information contains the old data values changed by the SQL statements of the transaction ·         Oracle has generated redo log entries in the redo log buffer of the System Global Area (SGA). The redo log record contains the change to the data block and the change to the rollback block. These changes may go to disk before a transaction is committed ·         The changes have been made to the database buffers of the SGA. These changes may go to disk before a transaction is committed   Note:   The data changes for a committed transaction, stored in the database buffers of the SGA, are not necessarily written immediately to the data files by the database writer (DBWn) background process. This writing takes place when it is most efficient for the database to do so. It can happen before the transaction commits or, alternatively, it can happen some times after the transaction commits.   When a transaction is committed, the following occurs: 1.      The internal transaction table for the associated undo table space records that the transaction has committed, and the corresponding unique system change number (SCN) of the transaction is assigned and recorded in the table 2.      The log writer process (LGWR) writes redo log entries in the SGA's redo log buffers to the redo log file. It also writes the transaction's SCN to the redo log file. This atomic event constitutes the commit of the transaction 3.      Oracle releases locks held on rows and tables 4.      Oracle marks the transaction complete   Note:   The default behavior is for LGWR to write redo to the online redo log files synchronously and for transactions to wait for the redo to go to disk before returning a commit to the user. However, for lower transaction commit latency application developers can specify that redo be written asynchronously and that transaction do not need to wait for the redo to be on disk.   The syntax of Commit Statement is   COMMIT [WORK] [COMMENT ‘your comment’]; ·         WORK is optional. The WORK keyword is supported for compliance with standard SQL. The statements COMMIT and COMMIT WORK are equivalent. Examples Committing an Insert INSERT INTO table_name VALUES (val1, val2); COMMIT WORK; ·         COMMENT Comment is also optional. This clause is supported for backward compatibility. Oracle recommends that you used named transactions instead of commit comments. Specify a comment to be associated with the current transaction. The 'text' is a quoted literal of up to 255 bytes that Oracle Database stores in the data dictionary view DBA_2PC_PENDING along with the transaction ID if a distributed transaction becomes in doubt. This comment can help you diagnose the failure of a distributed transaction. Examples The following statement commits the current transaction and associates a comment with it: COMMIT     COMMENT 'In-doubt transaction Code 36, Call (415) 555-2637'; ·         WRITE Clause Use this clause to specify the priority with which the redo information generated by the commit operation is written to the redo log. This clause can improve performance by reducing latency, thus eliminating the wait for an I/O to the redo log. Use this clause to improve response time in environments with stringent response time requirements where the following conditions apply: The volume of update transactions is large, requiring that the redo log be written to disk frequently. The application can tolerate the loss of an asynchronously committed transaction. The latency contributed by waiting for the redo log write to occur contributes significantly to overall response time. You can specify the WAIT | NOWAIT and IMMEDIATE | BATCH clauses in any order. Examples To commit the same insert operation and instruct the database to buffer the change to the redo log, without initiating disk I/O, use the following COMMIT statement: COMMIT WRITE BATCH; Note: If you omit this clause, then the behavior of the commit operation is controlled by the COMMIT_WRITE initialization parameter, if it has been set. The default value of the parameter is the same as the default for this clause. Therefore, if the parameter has not been set and you omit this clause, then commit records are written to disk before control is returned to the user. WAIT | NOWAIT Use these clauses to specify when control returns to the user. The WAIT parameter ensures that the commit will return only after the corresponding redo is persistent in the online redo log. Whether in BATCH or IMMEDIATE mode, when the client receives a successful return from this COMMIT statement, the transaction has been committed to durable media. A crash occurring after a successful write to the log can prevent the success message from returning to the client. In this case the client cannot tell whether or not the transaction committed. The NOWAIT parameter causes the commit to return to the client whether or not the write to the redo log has completed. This behavior can increase transaction throughput. With the WAIT parameter, if the commit message is received, then you can be sure that no data has been lost. Caution: With NOWAIT, a crash occurring after the commit message is received, but before the redo log record(s) are written, can falsely indicate to a transaction that its changes are persistent. If you omit this clause, then the transaction commits with the WAIT behavior. IMMEDIATE | BATCH Use these clauses to specify when the redo is written to the log. The IMMEDIATE parameter causes the log writer process (LGWR) to write the transaction's redo information to the log. This operation option forces a disk I/O, so it can reduce transaction throughput. The BATCH parameter causes the redo to be buffered to the redo log, along with other concurrently executing transactions. When sufficient redo information is collected, a disk write of the redo log is initiated. This behavior is called "group commit", as redo for multiple transactions is written to the log in a single I/O operation. If you omit this clause, then the transaction commits with the IMMEDIATE behavior. ·         FORCE Clause Use this clause to manually commit an in-doubt distributed transaction or a corrupt transaction. ·         In a distributed database system, the FORCE string [, integer] clause lets you manually commit an in-doubt distributed transaction. The transaction is identified by the 'string' containing its local or global transaction ID. To find the IDs of such transactions, query the data dictionary view DBA_2PC_PENDING. You can use integer to specifically assign the transaction a system change number (SCN). If you omit integer, then the transaction is committed using the current SCN. ·         The FORCE CORRUPT_XID 'string' clause lets you manually commit a single corrupt transaction, where string is the ID of the corrupt transaction. Query the V$CORRUPT_XID_LIST data dictionary view to find the transaction IDs of corrupt transactions. You must have DBA privileges to view the V$CORRUPT_XID_LIST and to specify this clause. ·         Specify FORCE CORRUPT_XID_ALL to manually commit all corrupt transactions. You must have DBA privileges to specify this clause. Examples Forcing an in doubt transaction. Example The following statement manually commits a hypothetical in-doubt distributed transaction. Query the V$CORRUPT_XID_LIST data dictionary view to find the transaction IDs of corrupt transactions. You must have DBA privileges to view the V$CORRUPT_XID_LIST and to issue this statement. COMMIT FORCE '22.57.53';

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  • SQL SERVER – Introduction to SQL Server 2014 In-Memory OLTP

    - by Pinal Dave
    In SQL Server 2014 Microsoft has introduced a new database engine component called In-Memory OLTP aka project “Hekaton” which is fully integrated into the SQL Server Database Engine. It is optimized for OLTP workloads accessing memory resident data. In-memory OLTP helps us create memory optimized tables which in turn offer significant performance improvement for our typical OLTP workload. The main objective of memory optimized table is to ensure that highly transactional tables could live in memory and remain in memory forever without even losing out a single record. The most significant part is that it still supports majority of our Transact-SQL statement. Transact-SQL stored procedures can be compiled to machine code for further performance improvements on memory-optimized tables. This engine is designed to ensure higher concurrency and minimal blocking. In-Memory OLTP alleviates the issue of locking, using a new type of multi-version optimistic concurrency control. It also substantially reduces waiting for log writes by generating far less log data and needing fewer log writes. Points to remember Memory-optimized tables refer to tables using the new data structures and key words added as part of In-Memory OLTP. Disk-based tables refer to your normal tables which we used to create in SQL Server since its inception. These tables use a fixed size 8 KB pages that need to be read from and written to disk as a unit. Natively compiled stored procedures refer to an object Type which is new and is supported by in-memory OLTP engine which convert it into machine code, which can further improve the data access performance for memory –optimized tables. Natively compiled stored procedures can only reference memory-optimized tables, they can’t be used to reference any disk –based table. Interpreted Transact-SQL stored procedures, which is what SQL Server has always used. Cross-container transactions refer to transactions that reference both memory-optimized tables and disk-based tables. Interop refers to interpreted Transact-SQL that references memory-optimized tables. Using In-Memory OLTP In-Memory OLTP engine has been available as part of SQL Server 2014 since June 2013 CTPs. Installation of In-Memory OLTP is part of the SQL Server setup application. The In-Memory OLTP components can only be installed with a 64-bit edition of SQL Server 2014 hence they are not available with 32-bit editions. Creating Databases Any database that will store memory-optimized tables must have a MEMORY_OPTIMIZED_DATA filegroup. This filegroup is specifically designed to store the checkpoint files needed by SQL Server to recover the memory-optimized tables, and although the syntax for creating the filegroup is almost the same as for creating a regular filestream filegroup, it must also specify the option CONTAINS MEMORY_OPTIMIZED_DATA. Here is an example of a CREATE DATABASE statement for a database that can support memory-optimized tables: CREATE DATABASE InMemoryDB ON PRIMARY(NAME = [InMemoryDB_data], FILENAME = 'D:\data\InMemoryDB_data.mdf', size=500MB), FILEGROUP [SampleDB_mod_fg] CONTAINS MEMORY_OPTIMIZED_DATA (NAME = [InMemoryDB_mod_dir], FILENAME = 'S:\data\InMemoryDB_mod_dir'), (NAME = [InMemoryDB_mod_dir], FILENAME = 'R:\data\InMemoryDB_mod_dir') LOG ON (name = [SampleDB_log], Filename='L:\log\InMemoryDB_log.ldf', size=500MB) COLLATE Latin1_General_100_BIN2; Above example code creates files on three different drives (D:  S: and R:) for the data files and in memory storage so if you would like to run this code kindly change the drive and folder locations as per your convenience. Also notice that binary collation was specified as Windows (non-SQL). BIN2 collation is the only collation support at this point for any indexes on memory optimized tables. It is also possible to add a MEMORY_OPTIMIZED_DATA file group to an existing database, use the below command to achieve the same. ALTER DATABASE AdventureWorks2012 ADD FILEGROUP hekaton_mod CONTAINS MEMORY_OPTIMIZED_DATA; GO ALTER DATABASE AdventureWorks2012 ADD FILE (NAME='hekaton_mod', FILENAME='S:\data\hekaton_mod') TO FILEGROUP hekaton_mod; GO Creating Tables There is no major syntactical difference between creating a disk based table or a memory –optimized table but yes there are a few restrictions and a few new essential extensions. Essentially any memory-optimized table should use the MEMORY_OPTIMIZED = ON clause as shown in the Create Table query example. DURABILITY clause (SCHEMA_AND_DATA or SCHEMA_ONLY) Memory-optimized table should always be defined with a DURABILITY value which can be either SCHEMA_AND_DATA or  SCHEMA_ONLY the former being the default. A memory-optimized table defined with DURABILITY=SCHEMA_ONLY will not persist the data to disk which means the data durability is compromised whereas DURABILITY= SCHEMA_AND_DATA ensures that data is also persisted along with the schema. Indexing Memory Optimized Table A memory-optimized table must always have an index for all tables created with DURABILITY= SCHEMA_AND_DATA and this can be achieved by declaring a PRIMARY KEY Constraint at the time of creating a table. The following example shows a PRIMARY KEY index created as a HASH index, for which a bucket count must also be specified. CREATE TABLE Mem_Table ( [Name] VARCHAR(32) NOT NULL PRIMARY KEY NONCLUSTERED HASH WITH (BUCKET_COUNT = 100000), [City] VARCHAR(32) NULL, [State_Province] VARCHAR(32) NULL, [LastModified] DATETIME NOT NULL, ) WITH (MEMORY_OPTIMIZED = ON, DURABILITY = SCHEMA_AND_DATA); Now as you can see in the above query example we have used the clause MEMORY_OPTIMIZED = ON to make sure that it is considered as a memory optimized table and not just a normal table and also used the DURABILITY Clause= SCHEMA_AND_DATA which means it will persist data along with metadata and also you can notice this table has a PRIMARY KEY mentioned upfront which is also a mandatory clause for memory-optimized tables. We will talk more about HASH Indexes and BUCKET_COUNT in later articles on this topic which will be focusing more on Row and Index storage on Memory-Optimized tables. So stay tuned for that as well. Now as we covered the basics of Memory Optimized tables and understood the key things to remember while using memory optimized tables, let’s explore more using examples to understand the Performance gains using memory-optimized tables. I will be using the database which i created earlier in this article i.e. InMemoryDB in the below Demo Exercise. USE InMemoryDB GO -- Creating a disk based table CREATE TABLE dbo.Disktable ( Id INT IDENTITY, Name CHAR(40) ) GO CREATE NONCLUSTERED INDEX IX_ID ON dbo.Disktable (Id) GO -- Creating a memory optimized table with similar structure and DURABILITY = SCHEMA_AND_DATA CREATE TABLE dbo.Memorytable_durable ( Id INT NOT NULL PRIMARY KEY NONCLUSTERED Hash WITH (bucket_count =1000000), Name CHAR(40) ) WITH (MEMORY_OPTIMIZED = ON, DURABILITY = SCHEMA_AND_DATA) GO -- Creating an another memory optimized table with similar structure but DURABILITY = SCHEMA_Only CREATE TABLE dbo.Memorytable_nondurable ( Id INT NOT NULL PRIMARY KEY NONCLUSTERED Hash WITH (bucket_count =1000000), Name CHAR(40) ) WITH (MEMORY_OPTIMIZED = ON, DURABILITY = SCHEMA_only) GO -- Now insert 100000 records in dbo.Disktable and observe the Time Taken DECLARE @i_t bigint SET @i_t =1 WHILE @i_t<= 100000 BEGIN INSERT INTO dbo.Disktable(Name) VALUES('sachin' + CONVERT(VARCHAR,@i_t)) SET @i_t+=1 END -- Do the same inserts for Memory table dbo.Memorytable_durable and observe the Time Taken DECLARE @i_t bigint SET @i_t =1 WHILE @i_t<= 100000 BEGIN INSERT INTO dbo.Memorytable_durable VALUES(@i_t, 'sachin' + CONVERT(VARCHAR,@i_t)) SET @i_t+=1 END -- Now finally do the same inserts for Memory table dbo.Memorytable_nondurable and observe the Time Taken DECLARE @i_t bigint SET @i_t =1 WHILE @i_t<= 100000 BEGIN INSERT INTO dbo.Memorytable_nondurable VALUES(@i_t, 'sachin' + CONVERT(VARCHAR,@i_t)) SET @i_t+=1 END The above 3 Inserts took 1.20 minutes, 54 secs, and 2 secs respectively to insert 100000 records on my machine with 8 Gb RAM. This proves the point that memory-optimized tables can definitely help businesses achieve better performance for their highly transactional business table and memory- optimized tables with Durability SCHEMA_ONLY is even faster as it does not bother persisting its data to disk which makes it supremely fast. Koenig Solutions is one of the few organizations which offer IT training on SQL Server 2014 and all its updates. Now, I leave the decision on using memory_Optimized tables on you, I hope you like this article and it helped you understand  the fundamentals of IN-Memory OLTP . Reference: Pinal Dave (http://blog.sqlauthority.com)Filed under: PostADay, SQL, SQL Authority, SQL Performance, SQL Query, SQL Server, SQL Tips and Tricks, T SQL Tagged: Koenig

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