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Raid recommendation please!

Discussion in 'Servers and Enterprise Solutions' started by Over Clocker, 12 May 2010.

  1. Over Clocker

    Man of Honour

    Joined: 17 Oct 2002

    Posts: 9,695

    Location: Retired Don

    Hi guys,

    Setting up a new server soon, and have become a bit behind on current RAID configs.

    What would your recommendations be for the following roles.

    Main server will be running Hyper V from Server 2008 R2 Enterprise

    1 VM will be the DC, DHCP, DNS, AD etc etc
    2nd VM will store folders, files, network programs, remote access (MS RD Web), WDS and Application streaming softare.

    What raid configs would you go with in this scenario??

    Cheers,

    Mal :)
     
  2. oddjob62

    Sgarrista

    Joined: 8 Nov 2002

    Posts: 9,128

    Location: NW London

    How many users?
    How many drives?
    How big?
    How much storage needed?
     
  3. daz

    Capodecina

    Joined: 18 Oct 2002

    Posts: 24,019

    Location: Bucks

    For running VMs, I'd go for RAID10 for the disk I/O.
     
  4. Vanilla

    Sgarrista

    Joined: 18 Oct 2002

    Posts: 9,361

    What's the IO profile of whatever will be on the servers? Tell us more about the apps listed.

    Mostly reads? Mostly writes? Mixture?

    File is easy, typically 75% read, 25% write.
     
  5. iaind

    Capodecina

    Joined: 26 Feb 2009

    Posts: 14,814

    Location: Exeter

    While RAID10 does give the best performance, it's also the highest cost so if it's not necessary then it would be a waste of money. Need more information really!
     
  6. daz

    Capodecina

    Joined: 18 Oct 2002

    Posts: 24,019

    Location: Bucks

    VMs always need as much disk I/O as possible, it's the most common bottleneck in any VM node.
     
  7. Over Clocker

    Man of Honour

    Joined: 17 Oct 2002

    Posts: 9,695

    Location: Retired Don

    20 main users
    200 very light users
    50 60 PCs / laptops
    Drives - not decided yet
    Usable space required - approx 1TB

    Usage - mixture of reads and writes. The app streaming, WDS etc is mostly reads. Folder & file areas is reads and writes.

    Cost will be a limiting factor really. Can go for 4 drives, 5 at the most.

    Should the physical server OS and the VMs sit on the same array, or should we make 2 arrays so separate physical disks?

    Cheers.
     
  8. Vanilla

    Sgarrista

    Joined: 18 Oct 2002

    Posts: 9,361

    Disk is the most common bottleneck in any server, app or array!

    Seen VM's sit fine on R1, R5 and R6 - it all depends on what the VMs are for and what the IO profile is. If you have 10 disks the read IO capability is the same as R1 and R5. Writes are where it gets funky.

    If the VM is hosting apps that run mostly reads then R6 that sucker!
    Some writes but mostly reads....consider R5
    Heavy writes? R1 / R10 all the way!
     
  9. SiD the Turtle

    Sgarrista

    Joined: 16 Nov 2003

    Posts: 9,695

    Location: On the pale blue dot

    +1

    I just finished putting together a new Hyper-V box with RAID10. It's a pretty expensive option but it gives you great performance while retaining redundancy.

    Our old Hyper-V box was RAID5 but it suffers from constant write requirements from the DC and SQL boxes.


    P.S. This is personal preference but I'm against using VMs as NAS boxes for file storage. If you have a VHD to host all your files you only need one file corruption to wipe out all of your files. Use a VM for the OS, but pass though to a physical set of disks IMO.
     
    Last edited: 13 May 2010
  10. SiD the Turtle

    Sgarrista

    Joined: 16 Nov 2003

    Posts: 9,695

    Location: On the pale blue dot

    Ideally you want the host OS on separate spindles to the VM array. We've got the OS set up as RAID1 (160GB, the smallest we could buy) and the VM disk as a 1TB RAID10 array.
     
  11. daz

    Capodecina

    Joined: 18 Oct 2002

    Posts: 24,019

    Location: Bucks

    It just tends to be worse on VM nodes because you don't have guaranteed disk I/O. So a couple of VMs decide to do a Windows update at the same time and your MS SQL server instance slows to a crawl. :p