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  • Building vs buying a server for an academic lab [closed]

    - by Roy
    I'm looking for advice on the classic build vs buy question. We need a new linux server to run Matlab computation on in our lab (academic). Matlab parallel computing toolbox licence allows up to 12 local workers so we are aiming at a 12 core server with 4GB memory per core (total of 48gb). The system will have an SSD for the OS and a raid-5 (4x2tb) for data. I looked around and found a (relatively) cheap vendor, Silicon Mechanics, that offers a system to our liking (specs below) for $6732. However, buying the components from newegg cost only $4464! The difference is $2268 which is 50% of the base cost. If buying from a company can be thought of as a sort of insurance, basically my premiums are of 50% of the base cost which to me sounds like a lot. Of course any downtime is bad, but the work is not "mission critical", i.e. if it takes a few days to fix it when it breaks its no the end of the world. If it takes weeks to months then its a problem. If it breaks 2-3 times in 3 years, not too bad. If it breaks every month not good. In term of build experience, I set up a linux cluster in grad school (from existing computers) and I build my home pcs but I never built a server before. The server components I'm thinking about: 1 x SUPERMICRO SYS-7046T-6F 4U Tower Server Barebone Dual LGA 1366 Intel 5520 DDR3 1333/1066/800 ($1,050) 12 x Kingston 4GB 240-Pin DDR3 SDRAM DDR3 1333 (PC3 10600) ECC Unbuffered Server Memory ($420) 2 x Intel Xeon E5645 Westmere-EP 2.4GHz LGA 1366 80W Six-Core ($1,116) 4 x Seagate Constellation ES 2TB 7200 RPM SATA 6.0Gb/s 3.5" ($1,040) 1 x SAMSUNG Internal DVD Writer Black SATA ($20) 1 x Intel 520 Series 2.5" 180GB SATA III MLC SSD $300 1 x LSI LSI00281 PCI-Express 2.0 x8 MD2 Low profile SATA / SAS MegaRAID SAS 9260CV-4i Controller Card, $695

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  • Bad performance with Linux software RAID5 and LUKS encryption

    - by Philipp Wendler
    I have set up a Linux software RAID5 on three hard drives and want to encrypt it with cryptsetup/LUKS. My tests showed that the encryption leads to a massive performance decrease that I cannot explain. The RAID5 is able to write 187 MB/s [1] without encryption. With encryption on top of it, write speed is down to about 40 MB/s. The RAID has a chunk size of 512K and a write intent bitmap. I used -c aes-xts-plain -s 512 --align-payload=2048 as the parameters for cryptsetup luksFormat, so the payload should be aligned to 2048 blocks of 512 bytes (i.e., 1MB). cryptsetup luksDump shows a payload offset of 4096. So I think the alignment is correct and fits to the RAID chunk size. The CPU is not the bottleneck, as it has hardware support for AES (aesni_intel). If I write on another drive (an SSD with LVM) that is also encrypted, I do have a write speed of 150 MB/s. top shows that the CPU usage is indeed very low, only the RAID5 xor takes 14%. I also tried putting a filesystem (ext4) directly on the unencrypted RAID so see if the layering is problem. The filesystem decreases the performance a little bit as expected, but by far not that much (write speed varying, but 100 MB/s). Summary: Disks + RAID5: good Disks + RAID5 + ext4: good Disks + RAID5 + encryption: bad SSD + encryption + LVM + ext4: good The read performance is not affected by the encryption, it is 207 MB/s without and 205 MB/s with encryption (also showing that CPU power is not the problem). What can I do to improve the write performance of the encrypted RAID? [1] All speed measurements were done with several runs of dd if=/dev/zero of=DEV bs=100M count=100 (i.e., writing 10G in blocks of 100M). Edit: If this helps: I'm using Ubuntu 11.04 64bit with Linux 2.6.38. Edit2: The performance stays approximately the same if I pass a block size of 4KB, 1MB or 10MB to dd.

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  • How do I copy files between harddrives on Ubuntu CLI?

    - by ed209
    I have a dedicated server with a 120gb main ssd. The server happens to come with a couple of 3000GB hard drives. I'd like to use them to back up my main drive. Preferably, I'd like one as an exact copy of the main SSD and the other with incremental backups of the mysql database and a user uploads file. These are the drives I have Disk /dev/sda: 120.0 GB, 120034123776 bytes 255 heads, 63 sectors/track, 14593 cylinders, total 234441648 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: 0x000f2e18 Device Boot Start End Blocks Id System /dev/sda1 2048 4196352 2097152+ 83 Linux /dev/sda2 4198400 5246976 524288+ 83 Linux /dev/sda3 5249024 234441647 114596312 83 Linux Disk /dev/sdb: 3000.6 GB, 3000592982016 bytes 255 heads, 63 sectors/track, 364801 cylinders, total 5860533168 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: 0x00000000 Disk /dev/sdb doesn't contain a valid partition table Disk /dev/sdc: 3000.6 GB, 3000592982016 bytes 255 heads, 63 sectors/track, 364801 cylinders, total 5860533168 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: 0x00000000 Disk /dev/sdc doesn't contain a valid partition table The first problem I have, is that I have no idea how to copy from one drive to another. Kind of embarrassing I know, but I don't know where to start. I'm thinking of this in terms of Mac OS cli where I'm able to copy between /Volumes - is there an equivalent? (there is nothing under /mnt or /media)

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  • Win7 'locking' process/files/folders?

    - by Dynde
    I've had a fair bit problems with sometimes files/folders/processes being 'locked' by Windows. The weird thing is, it's not like the traditional sense, I think, where tools like UnlockIT and wholockme would work. It seems that just giving it a little often helps - making me think it could either be the HDD, the memory, or something in Windows. A scenario: I go into a folder - don't open anything at all, go back up, cut or drag-move the folder to someplace else, it says "Action can't be completed because the folder or a file in it is open in another program". Waiting sometimes 20 seconds sometimes a little longer, and I can move it. Another scenario is deleting a bunch of files in a folder, and it appears that everything is gone, but then suddenly after a few seconds an .exe file pops back up, and I can't delete it. Waiting a few minutes, then pressing refresh and it's gone. I have the strangest feeling that there's a problem with either HDD or memory. I already tried disabling Windows indexing service with no luck. Does anyone have any ideas? EDIT: I should say, that I have a very fast system, 16 GB DDR3 RAM, i7-2600k CPU, SSD main HDD, so I really should not be experiencing any sort of problems, where one might say that it's "reasonable" for the system not to respond right away. Edit2: And I updated SSD firmware a couple months ago, so it shouldn't be bad release FW either

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  • How to verify TRIM/discard on encrypted swap?

    - by svarni
    I am using an encrypted swap partition via ecryptfs-setup-swap on my Ubuntu 13.04 computer using a SSD. I have manually set up trim for my ext4 root partition (simply by adding the "discard" option in /etc/fstab). I also manually ran fstrim on the root partition prior to booting and using dstat I saw that for a few seconds several GB/s of data have been written to the disk. That was presumably the effect of the trim command. These high writerates are reproducable by deleting huge files and have not occured before setting up trim, so I take them as evidence for working trim/discard. Manually enabling trim on my root partition has stopped the wearout of my precious new disk from 365 used reserved blocks (out of 6176 total) within three months down to 0 additional used reserved blocks within three additional months (data from SMART attributes). Because I want to minimize the wearout of my SSD I now would like to know whether my swap partition (which is encrypted using ecryptfs-setup-swap) also makes use of the trim/discard option. I tried sudo swapon -d -v /dev/mapper/cryptswap1 but did not receive particular information ("-v") about whether trim/discard ("-d") was applied. If unsupported, i would expect a message. Then I tried sudo dd if=/dev/sda6 count=1 BS=1M | xxd | less directly after booting and when no swapspace was used but I saw not only zeroes. I assume, when looking at freshly trimmed regions, the disk would send zeroes instead of reading random sectors (and according to some forums, (unencrypted) swap space is trimmed once upon boot). Long story short: Are there any ideas on how to test if trim is effectively used for my encrypted swap? And if not, any ideas on how to - at least manually, for once - trim the whole swap space? I wouldn't want to tinker with the partition itself, because I dont know if it needs to be reinitialized as (encrypted) swap - I dont want to be left with an unbootable system :)

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  • Most secure way to access my home Linux server while I am on the road? Specialized solution wanted

    - by Ace Paus
    I think many people may be in my situation. I travel on business with a laptop. And I need secure access to files from the office (which in my case is my home). The short version of my question: How can I make SSH/SFTP really secure when only one person needs to connect to the server from one laptop? In this situation, what special steps would make it almost impossible for anyone else to get online access to the server? A lot more details: I use Ubuntu Linux on both my laptop (KDE) and my home/office server. Connectivity is not a problem. I can tether to my phone's connection if needed. I need access to a large number of files (around 300 GB). I don't need all of them at once, but I don't know in advance which files I might need. These files contain confidential client info and personal info such as credit card numbers, so they must be secure. Given this, I don't want store all these files on Dropbox or Amazon AWS, or similar. I couldn't justify that cost anyway (Dropbox don't even publish prices for plans above 100 GB, and security is a concern). However, I am willing to spend some money on a proper solution. A VPN service, for example, might be part of the solution? Or other commercial services? I've heard about PogoPlug, but I don't know if there is a similar service that might address my security concerns? I could copy all my files to my laptop because it has the space. But then I have to sync between my home computer and my laptop and I found in the past that I'm not very good about doing this. And if my laptop is lost or stolen, my data would be on it. The laptop drive is an SSD and encryption solutions for SSD drives are not good. Therefore, it seems best to keep all my data on my Linux file server (which is safe at home). Is that a reasonable conclusion, or is anything connected to the Internet such a risk that I should just copy the data to the laptop (and maybe replace the SSD with an HDD, which reduces battery life and performance)? I view the risks of losing a laptop to be higher. I am not an obvious hacking target online. My home broadband is cable Internet, and it seems very reliable. So I want to know the best (reasonable) way to securely access my data (from my laptop) while on the road. I only need to access it from this one computer, although I may connect from either my phone's 3G/4G or via WiFi or some client's broadband, etc. So I won't know in advance which IP address I'll have. I am leaning toward a solution based on SSH and SFTP (or similar). SSH/SFTP would provided about all the functionality I anticipate needing. I would like to use SFTP and Dolphin to browse and download files. I'll use SSH and the terminal for anything else. My Linux file server is set up with OpenSSH. I think I have SSH relatively secured. I'm using Denyhosts too. But I want to go several steps further. I want to get the chances that anyone can get into my server as close to zero as possible while still allowing me to get access from the road. I'm not a sysadmin or programmer or real "superuser". I have to spend most of my time doing other things. I've heard about "port knocking" but I have never used it and I don't know how to implement it (although I'm willing to learn). I have already read a number of articles with titles such as: Top 20 OpenSSH Server Best Security Practices 20 Linux Server Hardening Security Tips Debian Linux Stop SSH User Hacking / Cracking Attacks with DenyHosts Software more... I have not implemented every single thing I've read about. I probably can't do that. But maybe there is something even better I can do in my situation because I only need access from a single laptop. I'm just one user. My server does not need to be accessible to the general public. Given all these facts, I'm hoping I can get some suggestions here that are within my capability to implement and that leverage these facts to create a great deal better security than general purpose suggestions in the articles above.

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  • ESXi 5.0 GP Exception 13 World 2157

    - by rihatum
    1st time with Esxi 5.0, I have read the whitebox hcl and it states my box as compatible (Dell 960 Optiplex), I burnt Esxi install onto a cd and booted off it (without changing anything in bios) I only had a sata ssd connected, a usb flash 4gb (which i would have installed esxi on), It started loading fine and half way through it dumped a purple / pink screen with : GP Exception 13 World 2157 This system have 5GB RAM (2x2GB and 1x1GB), Intel VT is active in bios, Any suggestions or thoughts ? Will be grateful for your support Kind regards

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  • Unix sort keys cause performance problems

    - by KenFar
    My data: It's a 71 MB file with 1.5 million rows. It has 6 fields All six fields combine to form a unique key - so that's what I need to sort on. Sort statement: sort -t ',' -k1,1 -k2,2 -k3,3 -k4,4 -k5,5 -k6,6 -o output.csv input.csv The problem: If I sort without keys, it takes 30 seconds. If I sort with keys, it takes 660 seconds. I need to sort with keys to keep this generic and useful for other files that have non-key fields as well. The 30 second timing is fine, but the 660 is a killer. More details using unix time: sort input.csv -o output.csv = 28 seconds sort -t ',' -k1 input.csv -o output.csv = 28 seconds sort -t ',' -k1,1 input.csv -o output.csv = 64 seconds sort -t ',' -k1,1 -k2,2 input.csv -o output.csv = 194 seconds sort -t ',' -k1,1 -k2,2 -k3,3 input.csv -o output.csv = 328 seconds sort -t ',' -k1,1 -k2,2 -k3,3 -k4,4 input.csv -o output.csv = 483 seconds sort -t ',' -k1,1 -k2,2 -k3,3 -k4,4 -k5,5 input.csv -o output.csv = 561 seconds sort -t ',' -k1,1 -k2,2 -k3,3 -k4,4 -k5,5 -k6,6 input.csv -o output.csv = 660 seconds I could theoretically move the temp directory to SSD, and/or split the file into 4 parts, sort them separately (in parallel) then merge the results, etc. But I'm hoping for something simpler since looks like sort is just picking a bad algorithm. Any suggestions? Testing Improvements using buffer-size: With 2 keys I got a 5% improvement with 8, 20, 24 MB and best performance of 8% improvement with 16MB, but 6% worse with 128MB With 6 keys I got a 5% improvement with 8, 20, 24 MB and best performance of 9% improvement with 16MB. Testing improvements using dictionary order (just 1 run each): sort -d --buffer-size=8M -t ',' -k1,1 -k2,2 input.csv -o output.csv = 235 seconds (21% worse) sort -d --buffer-size=8M -t ',' -k1,1 -k2,2 input.csv -o ouput.csv = 232 seconds (21% worse) conclusion: it makes sense that this would slow the process down, not useful Testing with different file system on SSD - I can't do this on this server now. Testing with code to consolidate adjacent keys: def consolidate_keys(key_fields, key_types): """ Inputs: - key_fields - a list of numbers in quotes: ['1','2','3'] - key_types - a list of types of the key_fields: ['integer','string','integer'] Outputs: - key_fields - a consolidated list: ['1,2','3'] - key_types - a list of types of the consolidated list: ['string','integer'] """ assert(len(key_fields) == len(key_types)) def get_min(val): vals = val.split(',') assert(len(vals) <= 2) return vals[0] def get_max(val): vals = val.split(',') assert(len(vals) <= 2) return vals[len(vals)-1] i = 0 while True: try: if ( (int(get_max(key_fields[i])) + 1) == int(key_fields[i+1]) and key_types[i] == key_types[i+1]): key_fields[i] = '%s,%s' % (get_min(key_fields[i]), key_fields[i+1]) key_types[i] = key_types[i] key_fields.pop(i+1) key_types.pop(i+1) continue i = i+1 except IndexError: break # last entry return key_fields, key_types While this code is just a work-around that'll only apply to cases in which I've got a contiguous set of keys - it speeds up the code by 95% in my worst case scenario.

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  • XenServer 6.0.2 path to installation media contains non-ascii characters

    - by cmaduro
    XenServer 6.0.2 install fails no matter what I do. I have confirmed that the md5 checksum on my ISO file is good. I tried installing from a mounted ISO file (remotely via iKVM). I tried installing from physical media. I tried installing from a bootable USB stick (using syslinux + contents of the ISO) All attempts have yielded the same result: When verifying the installation media, at 0% initializing, the following is reported: "Some packages appeared to be damaged." followed by a list of pretty much all the gz2 and rpm packages. If I skip the media verification the installer proceeds and then gives me an error when it reaches "Installing from base pack" at 0% which states "An unrecoverable error has occurred. The error was: 'ascii' codec can't decode byte 0xff in position 20710: ordinal not in range(128) Please refer to your user guide, or contact a Technical Support Representative, for further details" there is one option left which is to reboot. Apparently at some point during the processing of the repositories on the installation media non-ascii characters are found, which causes the installer to quit. How do I fix this? Here are my specs TYAN S8236 motherboard 2 AMD Opteron 6234 processors LSI2008 card connected to 2 1TB Seagate Constellation drives SATA, 1 500GB Corsair m4 SSD SATA and 1 Corsair Forse 3 - 64GB SSD SATA Onboard SATA connected to a slim DVD-+RW. Onboard SAS connected to 2 IBM ESX 70GB 10K SAS drives (for XenServer) 256GB memory ================================================================================= Comments: According to pylonsbook.com "chances are you have run into a problem with character sets, encodings, and Unicode" – cmaduro 10 hours ago A clue is provided by "vmware.com/support/vsphere5/doc/…; Data migration fails if the path to the vCenter Server installation media contains non-ASCII characters When this problem occurs, an error message similar to: 'ascii' codec can't decode byte 0xd0 in position 30: ordinal not in range(128) appears, and the installer quits unexpectedly during the data migration process. – cmaduro 10 hours ago This is an error that python throws. And guess what, the .py extention of the file you have to edit in this link community.spiceworks.com/how_to/show/1168 means the installer is written in python. Python is interpreted, so now to find the install file responsible for this error. – cmaduro 6 hours ago The file that generates the error upon verification is /opt/xensource/installer/tui/repo.py. The error message appears around line 359. – cmaduro 2 hours ago I am fairly sure that the install error is generated somewhere in repository.py as the backend.py file throws errors while methods in that file are being called. Perhaps all errors can be traced back to this file. – cmaduro 1 hour ago

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  • Nginx php-fpm high cpu usage

    - by Piotr Kaluza
    I have a problem with a high traffic wordpress, super high CPU load under nginx php-fpm, I am caching with apc, and memcached, spent 2-3 days tweaking configs and looking for answers it seems to me that php-fpm takes up all the cpu available no matter how many max_children i set if i set 5 then the load is 20% each, if i set 20 then the load adds up till 90% i tried static and dynamic server is 2x3.0Ghz 6GB Ram SSD in raid 10 on ubuntu 12.04 x64 utpime: 17:27:51 up 2:19, 1 user, load average: 29.79, 28.08, 26.29 what can be the issue?

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  • What iowait values are ok?

    - by alfish
    I am trying to find the bottleneck of a server running a fairly busy php/mysql site. My first culprit was io but iostat shows that on average iowait consumes only %3.60 of cpu time. here is the complete result of issuing iostat: avg-cpu: %user %nice %system %iowait %steal %idle 65.78 0.00 8.52 3.60 0.00 22.10 Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn sda 42.36 138.28 1754.70 408630278 5185216128 So I am wondering if the iowait is within acceptable range, and if not, whether switching from SATA to SSD would dramatically reduce it?

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  • Adaptec 5805 after reboot don't starting

    - by Rakedko ShotGuns
    After rebooting the system, the controller is not included. It only works if the computer is shut down and turn off. Late i update firmware "Adaptec RAID 5805 Firmware Build 18948" How to fix the problem? add Log Configuration summary Server name.....................raid_test Adaptec Storage Manager agent...7.31.00 (18856) Adaptec Storage Manager console.7.31.00 (18856) Number of controllers...........1 Operating system................Windows Configuration information for controller 1 ------------------------------------------------------- Type............................Controller Model...........................Adaptec 5805 Controller number...............1 Physical slot...................2 Installed memory size...........512 MB Serial number...................8C4510C6C9E Boot ROM........................5.2-0 (18948) Firmware........................5.2-0 (18948) Device driver...................5.2-0 (16119) Controller status...............Optimal Battery status..................Charging Battery temperature.............Normal Battery charge amount (%).......37 Estimated charge remaining......0 days, 16 hours, 12 minutes Background consistency check....Disabled Copy back.......................Disabled Controller temperature..........Normal (40C / 104F) Default logical drive task priorityHigh Performance mode................Dynamic Number of logical devices.......1 Number of hot-spare drives......0 Number of ready drives..........0 Number of drive(s) assigned to MaxCache cache0 Maximum drives allowed for MaxCache cache8 MaxCache Read Cache Pool Size...0 GB NCQ status......................Enabled Stay awake status...............Disabled Internal drive spinup limit.....0 External drive spinup limit.....0 Phy 0...........................No device attached Phy 1...........................No device attached Phy 2...........................No device attached Phy 3...........................1.50 Gb/s Phy 4...........................No device attached Phy 5...........................No device attached Phy 6...........................No device attached Phy 7...........................No device attached Statistics version..............2.0 SSD Cache size..................0 Pages on fetch list.............0 Fetch list candidates...........0 Candidate replacements..........0 69319...........................31293 Logical device..................0 Logical device name............. RAID level......................Simple volume Data space......................148,916 GB Date created....................09/19/2012 Interface type..................Serial ATA State...........................Optimal Read-cache mode.................Enabled Preferred MaxCache read cache settingEnabled Actual MaxCache read cache setting Disabled Write-cache mode................Enabled (write-back) Write-cache setting.............Enabled (write-back) Partitioned.....................Yes Protected by hot spare..........No Bootable........................Yes Bad stripes.....................No Power Status....................Disabled Power State.....................Active Reduce RPM timer................Never Power off timer.................Never Verify timer....................Never Segment 0.......................Present: controller 1, connector 0, device 0, S/N 9RX3KZMT Overall host IOs................99075 Overall MB......................4411203 DRAM cache hits.................71929 SSD cache hits..................0 Uncached IOs....................29239 Overall disk failures...........0 DRAM cache full hits............71929 DRAM cache fetch / flush wait...0 DRAM cache hybrid reads.........3476 DRAM cache flushes..............-- Read hits.......................0 Write hits......................0 Valid Pages.....................0 Updates on writes...............0 Invalidations by large writes...0 Invalidations by R/W balance....0 Invalidations by replacement....0 Invalidations by other..........0 Page Fetches....................0 0...............................0 73..............................10822 8...............................3 46138...........................4916 27184...........................15226 20875...........................323 16982...........................1771 1563............................5317 1948............................2969 Serial attached SCSI ----------------------- Type............................Disk drive Vendor..........................Unknown Model...........................ST3160815AS Serial Number...................9RX3KZMT Firmware level..................3.AAD Reported channel................0 Reported SCSI device ID.........0 Interface type..................Serial ATA Size............................149,05 GB Negotiated transfer speed.......1.50 Gb/s State...........................Optimal S.M.A.R.T. error................No Write-cache mode................Write back Hardware errors.................0 Medium errors...................0 Parity errors...................0 Link failures...................0 Aborted commands................0 S.M.A.R.T. warnings.............0 Solid-state disk (non-spinning).false MaxCache cache capable..........false MaxCache cache assigned.........false NCQ status......................Enabled Phy 0...........................1.50 Gb/s Power State.....................Full rpm Supported power states..........Full rpm, Powered off 0x01............................113 0x03............................98 0x04............................99 0x05............................100 0x07............................83 0x09............................75 0x0A............................100 0x0C............................99 0xBB............................100 0xBD............................100 0xBE............................61 0xC2............................39 0xC3............................69 0xC5............................100 0xC6............................100 0xC7............................200 0xC8............................100 0xCA............................100 Aborted commands................0 Link failures...................0 Medium errors...................0 Parity errors...................0 Hardware errors.................0 SMART errors....................0 End of the configuration information for controller 1 List item

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  • ZFS/Btrfs/LVM2-like storage with advanced features on Linux?

    - by Easter Sunshine
    I have 3 identical internal 7200 RPM SATA hard disk drives on a Linux machine. I'm looking for a storage set-up that will give me all of this: Different data sets (filesystems or subtrees) can have different RAID levels so I can choose performance, space overhead, and risk trade-offs differently for different data sets while having a few number of physical disks (very important data can be 3xRAID1, important data can be 3xRAID5, unimportant reproducible data can be 3xRAID0). If each data set has an explicit size or size limit, then the ability to grow and shrink the size limit (offline if need be) Avoid out-of-kernel modules R/W or read-only COW snapshots. If it's a block-level snapshots, the filesystem should be synced and quiesced during a snapshot. Ability to add physical disks and then grow/redistribute RAID1, RAID5, and RAID0 volumes to take advantage of the new spindle and make sure no spindle is hotter than the rest (e.g., in NetApp, growing a RAID-DP raid group by a few disks will not balance the I/O across them without an explicit redistribution) Not required but nice-to-haves: Transparent compression, per-file or subtree. Even better if, like NetApps, analyzes the data first for compressibility and only compresses compressible data Deduplication that doesn't have huge performance penalties or require obscene amounts of memory (NetApp does scheduled deduplication on weekends, which is good) Resistance to silent data corruption like ZFS (this is not required because I have never seen ZFS report any data corruption on these specific disks) Storage tiering, either automatic (based on caching rules) or user-defined rules (yes, I have all-identical disks now but this will let me add a read/write SSD cache in the future). If it's user-defined rules, these rules should have the ability to promote to SSD on a file level and not a block level. Space-efficient packing of small files I tried ZFS on Linux but the limitations were: Upgrading is additional work because the package is in an external repository and is tied to specific kernel versions; it is not integrated with the package manager Write IOPS does not scale with number of devices in a raidz vdev. Cannot add disks to raidz vdevs Cannot have select data on RAID0 to reduce overhead and improve performance without additional physical disks or giving ZFS a single partition of the disks ext4 on LVM2 looks like an option except I can't tell whether I can shrink, extend, and redistribute onto new spindles RAID-type logical volumes (of course, I can experiment with LVM on a bunch of files). As far as I can tell, it doesn't have any of the nice-to-haves so I was wondering if there is something better out there. I did look at LVM dangers and caveats but then again, no system is perfect.

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  • AMD Socket FM1 A8 3870 3.0Ghz ASUS F1A75-M LE

    - by Tracy
    I am building a new computer for my wife and plan on using an: AMD socket FM1 A8 3870 3.0Ghz quad core processor ASUS f1a75-M LE motherboard Corsair xms3 8gb 1600 memory (2x4) Western Digital Caviar Blue 750gb hd OCZ Vertex 120 gb SSD Coolmax blue 700 watt psu Pioneer 24x dvdrw HEC Blitz mid tower case Windows 7 Home Premium 64 bit Are there any recommended settings that I need to pay close attention too in the BIOS? For example, both the CPU and motherboard have integrated graphics (AMD Radeon HD 6550D and HD 6000, respectively).

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  • macbook pro for developer

    - by Michael Ellick Ang
    Which of the following choices would be more beneficial to developers ? 13 inch Macbook Pro, Core 2 Duo, 4 GB Memory, 128 GB SSD - $1550 - Faster Storage 13 inch Macbook Pro, Core 2 Duo, 8 GB Memory, 250 GB HD - $1600 - More Memory 15 inch Macbook Pro, Core i5, 4 GB Memory, 320 GB HD - $1800 - Better CPU Thanks.

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  • Please wait for User Profile Service... on WIndows 7 takes around 1-2 minutes to process

    - by Chris
    When loggging into our domain, after entering account credentials the log in process takes around 1-2 minutes before it gets past the User Profile Service, the rest of the process takes 2-3 secs. This effects all machines running Windows 7 Enteprise 32-bit and is on fairly high spec laptops (SSD drives, i5 2.93Ghz CPU, 4GB memory). Is there any way to speed this up or is this time delay acceptable? Thanks in advance.

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  • Drive not able to be added to Storage Spaces

    - by Bram Vanroy
    I am having difficulties trying to create a storage space. I have four Hard Drives in my computer. Samsung 128Gb SSD x2 Caviar Green 2TB Older 320 Gb drive I want to merge the two last ones. The problem is, that the 2TB drive does not show up in the configuration screen.: I formatted both hard drives so that can't be it. Any help is appreciated. Edit: larger view: http://bramvanroy.be/files/images/storagespaces.jpg

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  • What PSU would be needed for a mid-range computer?

    - by iconiK
    I am building a mid-range computer primarily for gaming and graphic design. With the following components, what power supply unit would be good, in terms of having ample power for future expansion, with good efficiency and quiet operation, but most important, reliability in the long (5+ years) run? Gigabyt GA-H67MA-UD2H LGA 1155 Intel Core i5 2300 2.8GHz Crucial CT2KIT51264BA1339 2x4GB Kit ASUS HD 6850 DirectCU Intel X25-V 40GB SSD 2xSeagate 7200.12 1TB HDD RAID 1 Antec NSK-3480 µATX Case

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  • Developer Notebook i5 or i7

    - by Cas Sakal
    I could not decide on which configuration below gives better performance for developers on a notebook(running VS.NET, SQL Server, no gaming); (A) i5 540M + SSD (Intel) or (B) i7 720M + 7200 RPM HDD (Western Digital) Since these two configurations(A, B) costs nearly same $ for me, I would like to buy the fastest one for my job environment. Please do not comment just buy this or that, if you can give an inference about your choice I would be appreciated. Thank you, cas

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  • Finder Using Nearly 100% CPU

    - by jerwood
    I'm having a problem where the Finder uses WAY too much CPU time. It's using up to 100% of one of my cores. I'm running 10.6.2 on a MacBook Pro w/ 6GB of RAM, plenty of fast (SSD) disk space. I also run DropBox and BackBlaze. I've tried disabling my third party stuff (DropBox and BackBlaze), but that doesn't seem to help. It's killing my battery life!

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  • Multi-word dma 2

    - by Streki
    Hi, after installation of XP MODE I have in device manager in IDE ATA/ATAPI controler on my SSD disk Multi-word dma 2 mode/same mode like XP mode BIOS/. I using AHCI mode in bios and w7. Its any choice to get back Ultra DMA 6 mode? Thanks for help.

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  • Is it reasonable that a random disk seek & read costs ~16ms?

    - by fzhang
    I am frustrated about the latency of random reading from a non-ssd disk. Based on results from following test program, it speeds ~16 ms for a random read of just 512 bytes without help of os cache. I tried changing 512 to larger values, such as 25k, and the latency did not increase as much. I guess it is because the disk seek dominates the time. I understand that random reading is inherently slow, but just want to be sure that ~16ms is reasonable, even for non-ssd disk. #include <sys/stat.h> #include <sys/time.h> #include <sys/types.h> #include <sys/unistd.h> #include <fcntl.h> #include <limits.h> #include <stdio.h> #include <string.h> int main(int argc, char** argv) { int fd = open(argv[1], O_RDONLY); if (fd < 0) { fprintf(stderr, "Failed open %s\n", argv[1]); return -1; } const size_t count = 512; const off_t offset = 25990611 / 2; char buffer[count] = { '\0' }; struct timeval start_time; gettimeofday(&start_time, NULL); off_t ret = lseek(fd, offset, SEEK_SET); if (ret != offset) { perror("lseek error"); close(fd); return -1; } ret = read(fd, buffer, count); if (ret != count) { fprintf(stderr, "Failed reading all: %ld\n", ret); close(fd); return -1; } struct timeval end_time; gettimeofday(&end_time, NULL); printf("tv_sec: %ld, tv_usec: %ld\n", end_time.tv_sec - start_time.tv_sec, end_time.tv_usec - start_time.tv_usec); close(fd); return 0; }

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