VA7100 LUN Raid 0+1 Raid 5DP

[James Raffeld]

Hello all,

I have a VA7100 with 1 90GB lun on 4 36 gb disk drives. The lun is 46% full and command view shows that the data is being stored in Raid 5dp mode. If I add one or two more disks to the array will it go back to raid 0+1 or do I have to remake the LUN? I looked at the manuals and could not find any details on this. Thanks for the help.

[James Raffeld]

Actually that should be six 36gb disks not four.

[Vincent Fleming]

If you want to force the unit to use RAID 0/1 at all times, you can change it from AutoRAID mode to RAID 0/1 mode - BUT, only if you delete all your LUNs.

Good luck!

[Roger_22 · Accepted solution]

Good question. But first, if this is motivated by performance problems, first look at the event log (logprn) and verify there are no hardware problems. If you???ve had a lot on entries in the last few days (and you have not being changing the configuration or cycling power), then call hp for help.

Next, if you???re still having performance problems in the Normal Resiliency Mode (the default setting), then get the latest firmware (HP17). This has two big performance improvements for sequential and high utilization workloads.

Now to your question. In the AutoRAID mode, once the controller can satisfy the needed capacity of the created LUNs (not the capacity actually written to, but the configured size of the LUN. In your case 90GB) in RAID 1+0 it will convert all the data to RAID 1+0. That being said, you should be there with 90GB -- Assuming 6 36GB disks. So, try the following:

1) Pre-HP13 firmware worked different, get the latest firmware.
2) Check to make sure you don???t have a failed disk. If so, get it replaced.
3) Make sure you are using the performance log information (armperf) to see the real allocation of RAID 1+0 and RAID 5DP. Any other status point merely reflects the RAID 1+0/AutoRAID switch setting.
4) The exact boundary of LUN size is difficult (read impossible for mere humans) to compute, and 90GB is close to the boundary. Make sure Hot Spare disks are set to 0 (this will not affect the ability of the controller to perform an AutoRebuild (that???s a whole other explanation).
5) If the above does not result in the array using only RAID 1+0, then one more disk will do the trick. Just plug it in ??? don???t create any LUNs.

Let me know how things turn out.

Roger