Why is UNRAID cool for home?

I’ve played with many storage technologies at home, ZFS being one of my favs when it comes to performance. But i’ve been looking for something that suits a typical home environment where power usage and capacity is usually more important than performance. Thats where UNRAID has come in…

UNRAID give me these advantages;

  • Different sized disks in a single pool (only requires largest disk as parity)
  • Files are distributed over all the disks – so even if you lost more than a single drive you still still have some of your data. Note : with parity drive you can handle a single drive failing without loosing anything, sorta like RAID4 – non distributed parity.
  • Power usage, since the files are stored on specific disks not all the disks need to power on to give you your file.
  • Runs on a USB stick – no large operating system required.
  • Crashplan module can be installed to provide backup options.


P4000 / Lefthand and Windows DSM (MPIO)

Steps to setup MPIO round robin and DSM with P4000 / Lefthand nodes

This example is windows 2008 with 2 x 1gbit nics

  1. Install HP DSM driver onto windows 2008  (this should also install MPIO feature on windows 2008)
  2. Setup 2 x IP’s on windows host – storage subnet (used with MPIO)
    1. Confirm you can ping target from both (enable one at a time – ensure there is no routing on your other nics)
  3. Provision storage and allow server read / write access to windows server (via initiator name)
  4. Open iSCSI on windows 2008
  5. Put in IP of target in discovery tab
  6. On first tab confirm that iSCSI drive is presented to host
  7. Click “connect” – check both auto-connect and use MPIO
    1. click advanced – chose MS iSCSI initiator, choose first IP and target IP. Click o.k. / o.k
    2. click advanced – chose MS iSCSI initiator, choose second IP and target IP. Click o.k. / o.k
    3. Repeat above per additional Nic
  8. Confirm via “devices” that there is x (as many targets as nics) targets per disk
    1. Within devices choose MPIO – change from vendor specific to “round robin”
      1. Note : read / write access to LUN is required when using “round robin” MPIO opposed to the default “vendor specific” which works with read only access. Else you will get an error – “not supported”
    2. Repeat above per “device”
  9. Confirm on Lefthand / P4000 CMC that the LUN has one connection per initiator Nic, and that each connection also has its DSM children (visible in CMC if working).

Confirm that the connection are as expected…

Run some disk benchmark utilities (iometer) and check that traffic is travelling over all the nics you have setup above. You can just use windows builtin task manager to do this.

Check that the right amount of connections are on the CMC for that particular LUN and initiator.  So if you had 3 nodes via 2 initiator nics you would actually have 8 active connections in total (1 per nic (2) and an additional for every nic to each nodes (6))

Note : There are some reported issues with DMS and data corruption. Although i have not seen this myself please be diligent when it comes to data backup esp when production data is involved.