Raid help

Discussion in 'General Hardware' started by pctweak, Mar 3, 2005.

  1. pctweak

    pctweak OSNN Junior Addict

    Messages:
    13
    I am somewhat new to raid 5. I am thinking of purchasing a PowerEdge 1800 with raid 5. If I only have 3 hard drives I will have disck stripping with parity? So if one drive fails I can swap out with a new drive? Will windows 2000 still be running if this happens. Should I get 4 drives? I guess any info you could tell me would be great.

    TOTAL $1152.00

    Module PowerEdge 1800

    Intel® Xeon™ processor at 2.8GHz/1MB Cache, 800MHz FSB

    FREE QUADRUPLE UPGRADE to 2GB DDR2 400MHz 2 Single Ranked DIMMs

    Primary Controller FREE! CERC 6-Channel SATA RAID Controller

    Onboard NIC

    Hard Drive Configuration
    Add-in SATA card RAID 5, Minimum 3 drives required

    3Yr BRONZE Support, Next Business Day Onsite

    Hard Drive's

    3 - 40GB 7200 RPM SATA Hard Drive
     
  2. trainmaster77

    trainmaster77 Moderator Political User Folding Team

    Messages:
    509
    Location:
    St. Louis/Chicago
    how often have you heard of drives failing? it doesnt happen often enough to worry about it. i would get 4 drives and raid0 them. as a matter of fact ..for as long as i can remember ive never had a drive go bad... just get a good power backup from apc and youre straight.

    those 40 gb 7200 rpm sata drives arent enough money to justify wasting one drive just for backup ... raid all 4 of them.
     
  3. pctweak

    pctweak OSNN Junior Addict

    Messages:
    13
    [font=&quot]
    True, but I need more then a tape backup for what the server is being used for. I will sacrifice some speed for redundancy and insurance we do not loose data.[/font]
     
  4. trainmaster77

    trainmaster77 Moderator Political User Folding Team

    Messages:
    509
    Location:
    St. Louis/Chicago
    how much are those drives? id buy 2 more haha raid0 4 of them and use the fifth for the backup. i think you can do it that way. I dunno, ive never used that many hard drives haha.
     
  5. LordOfLA

    LordOfLA Godlike!

    Messages:
    7,027
    Location:
    Maidenhead, Berkshire, UK
    for raid 5 to work you need 1 drive as parity and one drive to mirror the other
    so to have a one drive hotswap raid 5 you need 3 drives. after that increment by 2 each time you neede to add another drive.
     
  6. Zedric

    Zedric NTFS Guru Folding Team

    Messages:
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    Location:
    Sweden
    Huh? RAID 5 doesn't use parity drives, that's RAID 3. And what mirror? Increment by two? Why?

    RAID 5 has distributed parity blocks.
    Code:
    RAID 5:
    ======================
    [b] P[/b] = Parity information
    
    Disk 1	Disk 2	Disk 3
    ------	------	------
    |  [b]P[/b] |	|  1 |	|  2 |
    |  3 |	|  [b]P[/b] |	|  4 |
    |  5 |	|  6 |	|  [b]P[/b] |
    |  [b]P[/b] |	|  7 |	|  8 |
    |  9 |	|  [b]P[/b] |	| 10 |
    | 11 |	| 12 |	|  [b]P[/b] |
    |  [b]P[/b] |	| 13 |	| 14 |
    | 15 |	|  [b]P[/b] |	| 16 |
    ------	------	------
    RAID 5 needs a minimum of 3 disks. After that you can add more disks if you wish. The best price/performance ratio is at about 4-6 disks. So if you can afford it, get 4. And RAID 0 isn't an alternative. RAID 0 should only be used for temporary and non-critical storage. RAID 5 is redundant (for single disk failures), but still faster than RAID 1 (mirroring). The total available storage space of a RAID 5 array is the disk size times the number of disks minus one (C*(N-1), C is capacity, N is # of drives).
     
  7. pctweak

    pctweak OSNN Junior Addict

    Messages:
    13
    thanks I think I will go for raid 5 with 4 hard drives. Dell rips you off for that 4th 40gig and they make you buy atleaset 3, so I will see if I can order the same hard dirve from newegg of something.

    If I have 4 - 40gigs that will give me 120 gigs of space. That should last about 20 years for what we need it for, perfect!! thanks

    :)