Guide To RAID

Discussion in 'Links' started by grunger, Sep 2, 2005.

  1. grunger

    grunger Ancient Guru

    Messages:
    1,874
    Likes Received:
    0
    GPU:
    Palit GTX970 4GB
    Guide To RAID

    Over the last few weeks RAID seems to be comming up over and over the boards so here's a quick rundown:

    The Basics:

    RAID = Redundant Array Of Inexpensive Disks
    So you need 2 or more disks to create a raid array.

    Ideally the disks must be identical, same size, manufacturer and model. RAID will work with drives of different manufacturers/models/sizes, but the lowest raid performace and size will only be as good as the poorest drive.

    The Types:

    SATA RAID is raid using the newer Serial ATA disks, this is common feature on newer motherboards

    IDE RAID is raid using older Parallel ATA disks (IDE), this is an option on some motherboards or by the use of a PCI raid card

    SCSI RAID (Unsuprisingly) RAID Using a SCSI controller and disks - Very fast, very reliable and very expensive.

    The Flavors of RAID:

    RAID 0 = Striping, 2 or more disks become 1, using a stripe, when data is written it is written accross both disks in a stripe, each disk gets half each, this leads to faster access times as the heads don't have to move as far.
    The Benifits = Faster Access Times
    The Problems = If you loose 1 disk you loose the data on both

    RAID 1 = Mirroring = 2 disks are used in a mirror. The data is written to both disks - they are complete copies of each other
    The Benifits = Redundancy - If you loose a disk, no problems, the other takes over and no data is lost
    The Problems = 2X160Gb drives in a mirror = 160Gb space, so can be expensive

    RAID 5 = Parity and data is striped accross 3 or more drives, you have the speed increase of RAID 0, but the due to the parity bits the array can loose a drive without data loss.
    The Benifits = Good perfomance, and good redundancy
    The Problems = Cost - 3+ identical drives and a mid to high end RAID controller are required

    RAID 4 = Similar to RAID 5, but slower as a drive is used as a dedicated parity drive, which adds a bottleneck

    RAID 3 = Same as RAID 4, but with a different stripe size

    JBOD = This is an option on many RAID controllers, it stands for Just A Bunch Of Disks and is a way of having a bunch of different sized disks show up as 1 drive. No performance increase or redundancy is provided. I wouldn't say this is really a RAID array as such


    There You Go!
    Hope someone finds this usefull!
     
    Last edited by a moderator: Mar 11, 2006
  2. instantcrash

    instantcrash Active Member

    Messages:
    80
    Likes Received:
    0
    GPU:
    8800GTX 21' Widescreen HD Monitor
    Good basic guide to RAID! I vote sticky! :cheers:
     
  3. grunger

    grunger Ancient Guru

    Messages:
    1,874
    Likes Received:
    0
    GPU:
    Palit GTX970 4GB
    Thanks, just trying to get all the basics in 1 place!
     
  4. thecake90

    thecake90 Ancient Guru

    Messages:
    4,043
    Likes Received:
    0
    GPU:
    Nvidia 1060GTX
    thank you that helps but can I use SCSI drive with an nforce 4 sli motherboard and how do you raid two drives
     

  5. grunger

    grunger Ancient Guru

    Messages:
    1,874
    Likes Received:
    0
    GPU:
    Palit GTX970 4GB
    Ok, Part 2......
    Actually creating an array is different for each card/board

    Normally (after plugging the disks in) you will see the raid controller initialize (Promise/Adaptec/etc) and search for the disks, then you have the option of entering the raid options menu, CRTL+A on adaptec cards. From there there should be a menu with options to choose the drives to use, choose the type of RAID to use (RAID 0 or 1 will be the only options on most on-board RAID controllers - RAID 5 etc are normally only found on more expensive add-in cards), create, and initalise the array.

    For those planning on creating an array which will be booted from, be sure to check the boot BIOS is enabled on the controller, and that it is a selected boot option in the motherboard's BIOS.

    If you are planning on installing an operating system make sure you press F6 when prompted and have the RAID controller's driver diskette handy otherwise the drives will not be seen by the install process.
     
  6. grunger

    grunger Ancient Guru

    Messages:
    1,874
    Likes Received:
    0
    GPU:
    Palit GTX970 4GB
    You would need a SCSI raid card and 2 indentical scsi disks. I doubt your board has on-board SCSI RAID, very few boards do, the few that do are high-end server boards
     
  7. thecake90

    thecake90 Ancient Guru

    Messages:
    4,043
    Likes Received:
    0
    GPU:
    Nvidia 1060GTX
    thanks but give me an example of an motherborad that supports SCSI
     
  8. instantcrash

    instantcrash Active Member

    Messages:
    80
    Likes Received:
    0
    GPU:
    8800GTX 21' Widescreen HD Monitor
  9. thecake90

    thecake90 Ancient Guru

    Messages:
    4,043
    Likes Received:
    0
    GPU:
    Nvidia 1060GTX
  10. grunger

    grunger Ancient Guru

    Messages:
    1,874
    Likes Received:
    0
    GPU:
    Palit GTX970 4GB
    Someone was asking for a RAID Guide - i thought'd i'd bump this thread i did a while ago :)
     

  11. WildStyle

    WildStyle Ancient Guru

    Messages:
    15,302
    Likes Received:
    9
    GPU:
    MSI GTX 970 Gaming 4G
    Stuck and formatted a little. :)
     
  12. grunger

    grunger Ancient Guru

    Messages:
    1,874
    Likes Received:
    0
    GPU:
    Palit GTX970 4GB
    Cool Thanks! :)
     
  13. errorrrr

    errorrrr Master Guru

    Messages:
    362
    Likes Received:
    0
    GPU:
    MSI GTX 670
    My OS install still not recognizing my RAID config... and I put the diskette in... it's just not detecting it... it keep asking me for more stuff.... I have the ABIT KN8 SLI board...
     
  14. Sampson

    Sampson Master Guru

    Messages:
    363
    Likes Received:
    0
    GPU:
    Zotac 970GTX
    Yea i had the same problem as errorrr, when windows was installing and it asks if u want to setup a raid i pushed the key then it says insert disk and it just doesnt read it. I set the raid up before hand by following the steps located in the DFI Lanparty SLI-DR manual and still nothing. I will be reinstalling windows again soon so ill try again.
     
  15. cepher2101

    cepher2101 Master Guru

    Messages:
    529
    Likes Received:
    0
    GPU:
    eVGA 7900gs KO
    I thought RAID stood for Redundant Array of Independant Disks.
    I myself have a 1.6TB RAID 5 with 4 disks. I think it can be explained more easily that in this case, one disk is used as an image for others while the rest split up data. When one disk goes down, the parity can restore the rest of the information on the working disks and keep the system up until you can get a replacement...of which the array will rebuild itself to original settings. In my case, all the disks act as a parity, so that even if "the image" disk goes down, another will take it's spot. Of course you lose capacity. And if it has more information than the image can take, the image acts as a regular splitting disk. Hope that helps
     

  16. AGP2xCRetin

    AGP2xCRetin Member

    Messages:
    16
    Likes Received:
    0
    GPU:
    XFX Geforce 6800GT 256MB @400mhz
    RAID Editions

    erm anyone got any experience/opinions on whether WD (for example) 'raid edition' drives are better to use than ordinaries? They seem to have 8MB caches instead of 16 would this make a difference in this kind of purpose?

    thanks
     
  17. littledragon

    littledragon Member Guru

    Messages:
    151
    Likes Received:
    0
    GPU:
    6600GT
    What's the optimal block size for desktop use? I have 4 raptors in a raid0 config but it benches no faster than when I had 2 of them in a raid0. I left the block size at 64k, I was wondering if it'll go faster if I reduce it to 4k
     
  18. ShádyGuy

    ShádyGuy Active Member

    Messages:
    65
    Likes Received:
    0
    GPU:
    512mb 665/1630 XFX Geforce 7900GTX
    With 4 Raptors you should go RAID0+1 imo
     
  19. littledragon

    littledragon Member Guru

    Messages:
    151
    Likes Received:
    0
    GPU:
    6600GT
    Wasn't what I was asking but I'd go raid5 before I go raid 0+1
     
  20. ShádyGuy

    ShádyGuy Active Member

    Messages:
    65
    Likes Received:
    0
    GPU:
    512mb 665/1630 XFX Geforce 7900GTX
    opps from what i've read 128k is faster than 64k.can anyone confirm ?
     

Share This Page