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  • Do 7.2k SATA drives and a hardware raid controller always end with trouble?

    - by xelco52
    I'm reading the FreeNAS userguide and came across the statement: Note that hardware RAID configured as JBOD may still detach disks that do not respond in time; and as such may require TLER/CCTL/ERC-enabled disks to prevent drive dropouts. I'm using a '3Ware 9550SX-8LP RAID Controller' and see quite a few stories of people successfully running raid5 on 7.2k consumer SATA drives without issue. Are detached disks only a theoretical problem, or should I expect this to be a common occurrence?

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  • if i have two external hard drives connected to my computer by USB (2.0 i think) will they load with consistent letters?

    - by Bec
    (I'm using windows-7 and the hard drives are western digital with whatever formatting they came with from the factory) i'm thinking of setting up two different back-ups one through windows and one with the software that came with the drive (because windows gives me a system image but isn't very user-friendly for my files) but will my computer get confused and load them as different letters each time?

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  • fstab line for auto mount drive that all users can read/write

    - by evilblender
    I have installed a cable that connects from the CPU's SATA motherboard connection to a removable drives' ESATA connection. I would like to be able to swap drives on the ESATA connection and have all users be able to read and write to these drives. I have created the directory /archive/ where I would like the drive(s) to mount. The drives are all formatted Fat 32 - but in the future I may use HFS for formatting. When I used the command (as root): mount /dev/sdc1 /archive the drive was mounted (but read only) What can I use in my /etc/fstab file that will allow drives to be mounted and unmounted by all users on the system? (both reading and writing) Also, will I be able to mount and unmount these drives without shutting down? or will I need to reboot every time I want to change drives? Thank you. Jeff

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  • How can I boot a vm on Hyper-V 2012 when it has a virtual hard-drive missing?

    - by Zone12
    We have a Hyper-V 2012 server with 8 VM's on. We have attached extra virtual hard-drives to each of the computers to store backups on. These drives are stored on a NAS. After a power failure, we tried to boot the VM's and found that they couldn't be booted without the attached backup drives. We couldn't boot the NAS at that point and so we had to remove all the extra drives manually, boot the VM's and re-attach the drives at a later date when we got the NAS back up and running. These backup drives are non-essential to the running of the system. I would like to know if there is a way to boot a VM on Hyper-V 2012 with some of the hard-drives (scsi) missing so that we can recover automatically from a power failure.

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  • What free space thresholds/limits are advisable for 640 GB and 2 TB hard disk drives with ZEVO ZFS on OS X?

    - by Graham Perrin
    Assuming that free space advice for ZEVO will not differ from advice for other modern implementations of ZFS … Question Please, what percentages or amounts of free space are advisable for hard disk drives of the following sizes? 640 GB 2 TB Thoughts A standard answer for modern implementations of ZFS might be "no more than 96 percent full". However if apply that to (say) a single-disk 640 GB dataset where some of the files most commonly used (by VirtualBox) are larger than 15 GB each, then I guess that blocks for those files will become sub optimally spread across the platters with around 26 GB free. I read that in most cases, fragmentation and defragmentation should not be a concern with ZFS. Sill, I like the mental picture of most fragments of a large .vdi in reasonably close proximity to each other. (Do features of ZFS make that wish for proximity too old-fashioned?) Side note: there might arise the question of how to optimise performance after a threshold is 'broken'. If it arises, I'll keep it separate. Background On a 640 GB StoreJet Transcend (product ID 0x2329) in the past I probably went beyond an advisable threshold. Currently the largest file is around 17 GB –  – and I doubt that any .vdi or other file on this disk will grow beyond 40 GB. (Ignore the purple masses, those are bundles of 8 MB band files.) Without HFS Plus: the thresholds of twenty, ten and five percent that I associate with Mobile Time Machine file system need not apply. I currently use ZEVO Community Edition 1.1.1 with Mountain Lion, OS X 10.8.2, but I'd like answers to be not too version-specific. References, chronological order ZFS Block Allocation (Jeff Bonwick's Blog) (2006-11-04) Space Maps (Jeff Bonwick's Blog) (2007-09-13) Doubling Exchange Performance (Bizarre ! Vous avez dit Bizarre ?) (2010-03-11) … So to solve this problem, what went in 2010/Q1 software release is multifold. The most important thing is: we increased the threshold at which we switched from 'first fit' (go fast) to 'best fit' (pack tight) from 70% full to 96% full. With TB drives, each slab is at least 5GB and 4% is still 200MB plenty of space and no need to do anything radical before that. This gave us the biggest bang. Second, instead of trying to reuse the same primary slabs until it failed an allocation we decided to stop giving the primary slab this preferential threatment as soon as the biggest allocation that could be satisfied by a slab was down to 128K (metaslab_df_alloc_threshold). At that point we were ready to switch to another slab that had more free space. We also decided to reduce the SMO bonus. Before, a slab that was 50% empty was preferred over slabs that had never been used. In order to foster more write aggregation, we reduced the threshold to 33% empty. This means that a random write workload now spread to more slabs where each one will have larger amount of free space leading to more write aggregation. Finally we also saw that slab loading was contributing to lower performance and implemented a slab prefetch mechanism to reduce down time associated with that operation. The conjunction of all these changes lead to 50% improved OLTP and 70% reduced variability from run to run … OLTP Improvements in Sun Storage 7000 2010.Q1 (Performance Profiles) (2010-03-11) Alasdair on Everything » ZFS runs really slowly when free disk usage goes above 80% (2010-07-18) where commentary includes: … OpenSolaris has changed this in onnv revision 11146 … [CFT] Improved ZFS metaslab code (faster write speed) (2010-08-22)

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  • Exchange Server 2007 Setup

    - by AlamedaDad
    Hi, I'm working on a upgrade to Exchange 2007 and I wanted to get some advise on hardware choices. We currently have an Exchange 2003 STD server with 400 users split between 6 AD Sites, that is housed on a single server. We need to move to a redundant, fault tolerant system to support our users. I'm planning on installing 2 Dell 1950 servers with W2k8-std to act as CAS and Hub servers, with NLB to allow abstraction of the actual server name to the users. There won't be an edge system since we have a Barracuda box already that will handle in/out spam/virus filtering. Backend I'm planning on 2 mailbox servers which will be Dell 2950s with 16GB RAM, 2 either dual-core or quad-core CPUs and 6 300GB SAS drives in some RAID config. These systems will be clustered using W2k8 Ent clustering and running CCR in Exchange. My questions are as follows: Is 16GB enough RAM for serving that many mailboxes along with the windows clustering and ccr? I'm trying to figure out disk layouts and I'm unsure of whether to use all local disk or some local and some SAN, via an OpenFiler iSCSI server. The SAN would be a Dell 2850 with 6 - 300GB SCSI drives and a PERC controller to slice as I want, with 8GB RAM. Option 1: 2 drives, RAID 1 - OS 2 drives, RAID 1 - Logs 2 drives, RAID 1 - Mail stores Option 2: 2 drives, RAID 1 - OS and logs 4 drives, RAID 5 - Mail Stores and scratch space for eseutil. Option 3: 2 drives, RAID 1 - OS 2 drives, RAID 1 - Logs 2 drives, RAID 0 - scratch space ~300GB iSCSI volume for mail stores Option 4: 2 drives, RAID 1 - OS 4 drives, RAID 5 - scratch space ~300GB iSCSI volume for mail stores ~300GB iSCSI volume for logs I have 2 sockets for CPUs and need to chose between dual and quad cores. The dual core have faster clocks but less cache and I'm thinking older architecture. Am I better off with more cores and cache while sacraficing clock speed? I am planning on adding the new E2K7 cluster to the E2K3 server and then move each mailbox over, all at once, then remove the old server. This seems more complicated than simply getting rid of the 2003 server and then adding the 2007 cluster and restoring the mailboxes using PowerControls or exmerge. The migration option lets me do this on my time, where a cutover means it all needs to work at once. If I go with the cutover method, how can I prebuild the servers and add them to the domain right after removing the 2003 server, or can't I? I think the answer is no and the migration is my only real option if I want to prebuild. I need to also migrate about 30GB of Public Folders. Is there anything special about this, other than specifying in the E2K7 install that I want older Outlook clients and PF's setup? I guess I could even keep the E2K3 server to host just the PFs? Lastly, if I have a mix of Outlook 200, 2003 and 2007 what do I need to do to make sure they all have access to the GAL and OAB? At time of cutover, we'll be at like 90% 2007, but we will have some older stuff around. My plan is to use Outlook Anywhere on laptops that are used outside the physical network. Are there any gotchas involved in that? I'm even thinking about using is for all Outlook clients, does anyone do that? The reason I'm considering it is that our WAN is really VPN tunnels over internet connections, so not a fully messhed, stable WAN. Thank you all very much for the assistance in advance and I look forward to discussion of these points! Regards...Michael

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  • PostgreSQL server: 10k RPM SAS or Intel 520 Series SSD drives?

    - by Vlad
    We will be expanding the storage for a PostgreSQL server and one of the things we are considering is using SSDs (Intel 520 Series) instead of rotating discs (10k RPM). Price per GB is comparable and we expect improved performance, however we are concerned about longevity since our database usage pattern is quite write-heavy. We are also concerned about data corruption in case of power failure (due to SSDs write cache not flushing properly). We currently use RAID10 with 4 active HDDs (10k 146GB) and 1 spare configured in the controller. It's a HP DL380 G6 server with P410 Smart Array Controller and BBWC. What makes more sense: upgrading the drives to 300GB 10k RPM or using Intel 520 Series SSDs (240GB)?

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  • How to (hardware) RAID 10 on Ubuntu 10.04 LTS with 4 drives and motherboard with RAID contoller

    - by lollercoaster
    I have 4 500GB hard drives. I set up a RAID 10 in BIOS, much like shown here: http://www.supermicro.com/manuals/other/RAID_SATA_ESB2.pdf Then I followed these instructions: http://www.unrest.ca/Knowledge-Base/configuring-mdadm-raid10-for-ubuntu-910 Basically I cannot get it to work. I go through the instructions when I get to the "partition" section of the install, creating 4 RAID 1's (2 partitions on each drive, one for primary and one for swap space), then combining to make a RAID 10. Unfortunately it still shows 2 partitions, one 500 GB and another being 36GB for some reason. Any ideas? I think best would be if anyone had found good instructions (step by step) for how to do this...I've been googling for hours and haven't found anything...

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  • Enabled storing Bitlocker keys in Active Directory, is there a way to upload keys of drives encrypted before this?

    - by Rossaluss
    We have enabled storing of Bitlocker keys within the device object on Active Directory, however before this was implemented, we had encrypted 100+ devices using bitlocker and we've only found ways to upload the key to AD when enabling bitlocker for the first time on an install. Does anybody know of a way where we can upload all the keys for all the devices which already had their drives encrypted with Bitlocker into their respective device objects in AD? Or are we going to have to decrypt and re-encrypt all the devices on the floor? (Google seems to say this is what we're going to have to do, however we're no experts in Bitlocker, so may have missed something) When we go into Manage Bitlocker of an already encrypted device, we only get the same options of saving the key to a file, a memory stick or printing it out, no option is available to save to AD etc. Any help would be appreciated.

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  • How to rescan and remount drives on Ubuntu Hardy or Jaunty?

    - by pts
    When I connect an USB drive to an Ununtu Hardy and Jaunty system, the system mounts the partitions found on the drive, and opens a Nautilus window for each mounted partitions. Within Nautilus, I am able to unmount partitions. What I need is a command or action which forces the system to rescan the available drives and partitions, and automount each not mounted partition, including those which I've manually unmounted from Nautilus. sudo /etc/init.d/udev restart or ... reload doesn't do this. As of now, I just unplug the USB drive, and commect it again, which will force a scan and a mount on that drive. But I want to do force the rescan and remount without unplugging anything, preferably without the user having the know device or drive names.

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  • Why do msi installations use slower drives over faster ones in windows 7?

    - by Joshua C
    I have noticed that the slowest drive in my system is used most during an msi installation. I mainly notice this when running windows updates but it seems to be msi installs in general. The setup I last saw this occur on was running Windows 7 with the following drives: Sata: 240GB SSD NTFS ~515MB/s Operating system drive 1TB NTFS ~110MB/s Firewire: 4TB ExFAT ~80MB/s I would think that windows would choose the fastest drive with available space for temporary files. But it will instead choose the external drive with the slowest transfer speed. I could also understand choosing the 1TB for not being an ssd in an attempt to preserve the longevity of the ssd write capacity. Why does this happen? Is there a way to force these installations to use the OS drive or a specific drive?

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  • How to use BT or emule across 2 or more hard drives?

    - by the searcher
    One difficulty with BT or emule is that, when the hard drive is full, we constantly need to move older files to a new hard drive so that we can download newer files. We can change BT or emule's setting so that the folder for downloading points to the new hard drive, but then, what if emule haven't finished downloading for some files that are hard to find, and it is 92% done... in that case, we would like to keep the old setting so that when the last 8% arrives, it can go into the correct file. (and same for BT, if we haven't finished some file or if we want to seed something later). So is there a good way to let BT or emule point to 2 hard drives, or somehow let the new hard drive "merge" into the existing hard drive / folder?

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  • Why are hard drives moving to 4096 byte sectors, vs. 512 byte sectors?

    - by Chris W. Rea
    I've noticed that some Western Digital hard drives are now sporting 4K sectors, that is, the sectors are larger: 4096 bytes vs. the long-standing standard of 512 bytes. So: What's the big deal with 4K sectors? Is it marketing hype, or a real advantage? Why should somebody building a new PC care, or not, about 4K sectors? Why is this transition taking place now? Why didn't it happen sooner? Are there things to look out for when buying a 4K sector hard drive? e.g. incompatibility? Anything else we should know about 4K sectors?

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  • RAID--0 " TWO " DRIVES SSD ONLY Should I use on-board / Software RAID OR a RAID Card / Control

    - by Wes
    I am looking at going with a TWO Drive Only SSD RAID-0 Configuration And was wondering if I would get better performance / Speed from the Use of a RAID Controller / Card Verses just using the Software RAID on my Mother Board. I have herd conflicting reports , Again I only Plan on Running " 2 " SSD Drives in RAID-0 Config I have No- problem spending the extra money for a good controller but only if I am going to benifit performance wise , Otherwise if there is no notable Gain I will just use the Software RAID that my HP-180-T came with Intel- 3.33 GHZ , 6-Core , 12-GB of DDR-3. I have a huge External drive for All Storage and am not concerned about Data loss just looking for pure speed. And if a Controller will benifit my performance Wht type of card would one suggest?

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  • Do I need to run a verfication on LTO tape backups even though the drives themselves perform verification as they write?

    - by ObligatoryMoniker
    We have an LTO-3 Tape drive in a Dell media library that we use for our tape backups. The article about LTO on Wikipedia states that: LTO uses an automatic verify-after-write technology to immediately check the data as it is being written, but some backup systems explicitly perform a completely separate tape reading operation to verify the tape was written correctly. This separate verify operation doubles the number of end-to-end passes for each scheduled backup, and reduces the tape life by half. What I would like to know is, do I need my backup software (Backup Exec in this case) to perform a verify on these tapes or is the verify-after-write technology inherent in LTO drives sufficient? I would also be curious if Backup Exec understands the verify-after-write technology enough to alert me if that technology couldn't veryify the data or will it just ignore it making it useless anyway since even if the drive detecs a problem I would never know about it.

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  • Is there a limit on the number of USB external drives?

    - by Beska
    I've got three external HDDs, all My Books, 500 GB, 750 GB, and 1 TB. If I hook one or two of them up to a computer, everything seems fine. If I hook all three of them to a computer (I've tried this on two different computers, one running Windows XP, one running Windows Vista), the bootup time goes up by more than an order of magnitude. It can suddenly take about 10-20 minutes to boot the machine, whereas before it might take a minute. All three drives work fine on their own. I'm not using any kind of hub; all three are plugged directly into the machine. Is this associated with some kind of inherent limit in USB? Is this bad hardware design in the CPU box? Is this a My Book problem?

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  • How full is too full for mechanical hard drives?

    - by Sunny Molini
    I have heard many claim that it doesn't matter how full a drive is until it starts cutting into temp and virtual memory space. This doesn't make sense to me, given the nature of how the data is transacted on a hard drive. The inside of the platter presents less data per revolution than the outside of the drive does, by significant factors. The inside 40% of the radius of full size hard drive is used for the spindle, so only the outside 60% is used for data storage, but that still means that the inside track of a hard drive presents data 60% slower than the outside track. By my calculation, a Hard drive that is only 10% full should perform about 2.25 times faster than a hard drive that is 90% full, assuming that the flow is constrained by other factors. Am I wildly off base here? For all the drives I know, even the top speeds of the first 1% of the drive would be well within the bandwidth provided by a SATA 2 connection.

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  • 4K sectors transition: Why are hard drives moving to 4096 byte sectors, vs. 512 byte sectors?

    - by Chris W. Rea
    I've noticed that some Western Digital hard drives are now sporting 4K sectors, that is, the sectors are larger: 4096 bytes vs. the long-standing standard of 512 bytes. So: What's the big deal with 4K sectors? Is it marketing hype, or a real advantage? Why should somebody building a new PC care, or not, about 4K sectors? Why is this transition taking place now? Why didn't it happen sooner? Are there things to look out for when buying a 4K sector hard drive? e.g. incompatibility? Anything else we should know about 4K sectors?

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  • What is the value/cost of enabling "spread spectrum clocking" on my hard drives?

    - by Stu Thompson
    I'm building up a biggish NAS box (10x WD RE4 2TB SATA RAID10) and ran into some problems. During the course of my research, debugging, investigations, etc, I discovered a jumper on the physical drives labeled "spread spectrum clocking". After some googling about this on teh internets, it seems to be a feature that some suggest (without reference or explanation) enabling in 'a storage configuration' that makes the drive less sussesptable to EMI. But why? I've got three core questions: Why is this feature not enabled by default? What are the actual benefits? Are there any costs?

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  • How do I put back different SCSI hard drives into their original RAID arrays across different servers?

    - by Edgar
    I have potentially a big mess in my hands: I received today a box with several hard drives that used to be connected to different servers each one of them using an unknown - at least as of right now- RAID configuration. Regretfully, these are not marked and I'm not sure how to go about putting them back into their original servers. Currently I don't have much more information: I don't know what type of array was being used on each instance and I don't have any specifics about the RAID controller originally used on each one of the servers (currently these servers are at a remote location with no easy access). Is there a way to sort through this mess? What would be the consequences of using trial and error to go about it? This might be a very basic question but I don't have much experience dealing with RAID arrays.

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  • In Linux, is it possible to get a listing of drives' disk space usage that also shows volume labels?

    - by DavidH
    I know about df, of course, but df does not output volume labels. I have 5 USB hard drives plugged into my NAS box, and would love to know which is which. Current df output: Filesystem Size Used Avail Use% Mounted on /dev/sda1 27G 2.2G 24G 9% / none 56M 476K 55M 1% /dev none 60M 0 60M 0% /dev/shm none 60M 332K 59M 1% /var/run none 60M 0 60M 0% /var/lock none 60M 0 60M 0% /lib/init/rw /dev/sde1 150G 102G 48G 68% /media/usb0 /dev/sdb1 299G 196G 103G 66% /media/usb1 /dev/sdc1 233G 183G 51G 79% /media/usb2 /dev/sdd1 233G 209G 25G 90% /media/usb3 /dev/sdf1 150G 101G 49G 68% /media/usb4

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  • Best way to syn a file between 2 or more drives?

    - by jasondavis
    I have a special file that I edit daily, it is somewhat like a large text file but a little more to it then that. I have a copy on my main desktop and a copy of the file on a USB drive as well. I would like a way to open up either file (from the USB drive or from my desktop drive) and be able to edit and save the file and have it stay updated on both drives. What is a lightweight and easy method of doing this? I do not need anything fancy

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  • Do RAID controllers commonly have SATA drive brand compatibility issues?

    - by Jeff Atwood
    We've struggled with the RAID controller in our database server, a Lenovo ThinkServer RD120. It is a rebranded Adaptec that Lenovo / IBM dubs the ServeRAID 8k. We have patched this ServeRAID 8k up to the very latest and greatest: RAID bios version RAID backplane bios version Windows Server 2008 driver This RAID controller has had multiple critical BIOS updates even in the short 4 month time we've owned it, and the change history is just.. well, scary. We've tried both write-back and write-through strategies on the logical RAID drives. We still get intermittent I/O errors under heavy disk activity. They are not common, but serious when they happen, as they cause SQL Server 2008 I/O timeouts and sometimes failure of SQL connection pools. We were at the end of our rope troubleshooting this problem. Short of hardcore stuff like replacing the entire server, or replacing the RAID hardware, we were getting desperate. When I first got the server, I had a problem where drive bay #6 wasn't recognized. Switching out hard drives to a different brand, strangely, fixed this -- and updating the RAID BIOS (for the first of many times) fixed it permanently, so I was able to use the original "incompatible" drive in bay 6. On a hunch, I began to assume that the Western Digital SATA hard drives I chose were somehow incompatible with the ServeRAID 8k controller. Buying 6 new hard drives was one of the cheaper options on the table, so I went for 6 Hitachi (aka IBM, aka Lenovo) hard drives under the theory that an IBM/Lenovo RAID controller is more likely to work with the drives it's typically sold with. Looks like that hunch paid off -- we've been through three of our heaviest load days (mon,tue,wed) without a single I/O error of any kind. Prior to this we regularly had at least one I/O "event" in this time frame. It sure looks like switching brands of hard drive has fixed our intermittent RAID I/O problems! While I understand that IBM/Lenovo probably tests their RAID controller exclusively with their own brand of hard drives, I'm disturbed that a RAID controller would have such subtle I/O problems with particular brands of hard drives. So my question is, is this sort of SATA drive incompatibility common with RAID controllers? Are there some brands of drives that work better than others, or are "validated" against particular RAID controller? I had sort of assumed that all commodity SATA hard drives were alike and would work reasonably well in any given RAID controller (of sufficient quality).

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  • Ripping CD Audio simultaneously from 2 drives on one PC via USB or PATA - rip accuracy preserved?

    - by Rob
    I'm considering ripping audio (reading audio) from CDs using 2 drives simultaneously to speed up the process of ripping the CDs - i.e. 2 at a time rather than 1. Are there any issues with achieving maximum rip accuracy? In general I wondered if people have tried this and if the simultaneous streams from both rip activities would overload the host machine and cause packet loss or read retries resulting in a sub-standard CD-DA Audio CD rip? If it just means the rip is slightly slower (but still faster than sequentially doing one rip followed by another) but still of maximum accuracy then that is OK for me. I will be using dbPowerAmp to rip the CDs and converting to FLAC lossless format. Specific examples: There are 2 machines I intend to do it on: A Toshiba NB100 1.6Ghz Atom netbook, 2Gb RAM, running Windows XP Home with 1 external LG DVD/CD burner and external 1 LG Blu-ray burner attached via USB 2.0, ripping to the machine's 5400rpm internal hard drive. This rips from one CD drive very well, more than adequate, it is a nippy, fast little machine for its specification. A Desktop PC running Windows 7 Home Premium with MSI P4M900M2-L/ MS-7255v2.0 motherboard and 1.86Ghz Intel Core 2 Duo E6320, 7200rpm hard drive and 2Gb RAM, with an internal LG PATA DVD/CD burner (master) and a Philips DVD/CD burner (slave) on the same PATA bus (perhaps separate buses would be another option to consider here). Thoughts?

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