Unallocated space is too small for active hot spare

[jane zhang]

Hello all,

we have autoraid 12H attached to our N class server and in the array are mixed 9GB and 36GB drive.

One 36GB drive failed last week and give me the following message.


Its current value is MAJORWARNING(3).

Event data from monitor:

......

Summary:
Disk Array at hardware path :
Active Hot Spare request can not be accomplished. Not enough physical
space to provide active hot spare.

Since this machine is out of HP support and is going to reire soon, I am not willing to order another a 36GB drive to replace it.

However I have a 18GB disk drive available and I intended to replace the 36GB drive with my 18GB drive, will this fix my problem? does the size make difference here?

Thanks,

Jane

[Patrick Wallek]

Yes, size does matter in this case. You must have unallocated space equal to the size of the largest disk drive in order for Active Hot Spare to work.

So replacing a 36GB drive with an 18GB drive won't help you much in this case.

[jane zhang]

Hi patrick,

I have put the used disk and manually include the disk, the array become ready( status) and I got the following part from arraydsp:

--- Disk space usage --------------------
Total physical = 295229 MB *
Allocated to LUNs = 196000 MB *
Used as Active Hot spare = 34732 MB *
Used by non-included disks = 0 MB *
Used for Redundancy = 53618 MB *
Unallocated (avail for LUNs) = 10879 MB *
-----------------------------------------

I remember if the size of the active hot spare is as big as the size of the largest drive, it is OK. ( before I insert the 18gb drive, the size of the active hot spare is 0)

Is that correct?

Thanks,

Jane

[Patrick Wallek]

OK, here is what I think happened:

You have Active Hot Spare enabled and had a disk go bad. Some of the Active Hot Spare space was used to rebuild the array. You still had some space not allocated to LUNs that could be used for Active Hot Spare, but now there wasn't enough space (unallocated space not equal to largest drive size) for the full Active Hot Spare, so you got the error message.

Then you inserted and included the 18GB disk. This then increased your unallocated space by 18GB. You then had enough unallocated space for the Active Hot Spare to be usable again.

It appears from your last output that you are now fully redundent and back to normal.

[jane zhang]

Hi Patrick,

Thanks for the reply. what your guessed is almost true except we have 0 unallocated spaced.

I put part of the arraydsp display here.

before the disk went bad and then auto-rebuild finished:

--------------------------------------------
Array State = WARNING
Server name = fcdsjus
Array type = 3
Mfg. Product Code = IJMTU00003

--- Disk space usage --------------------
Total physical = 277863 MB *
Allocated to LUNs = 196000 MB *
Used as Active Hot spare = 0 MB *
Used by non-included disks = 0 MB *
Used for Redundancy = 81863 MB *
Unallocated (avail for LUNs) = 0 MB *
-----------------------------------------

THE FOLLOWING WARNING(S) EXIST:
- Active Hot Spare Unavailable

here is the info After the 36GB drive was replaced and the balancing finished.

----------------------------------------------------
Array State = READY
Server name = fcdsjus
Array type = 3
Mfg. Product Code = IJMTU00003

--- Disk space usage --------------------
Total physical = 295229 MB *
Allocated to LUNs = 196000 MB *
Used as Active Hot spare = 34732 MB *
Used by non-included disks = 0 MB *
Used for Redundancy = 53618 MB *
Unallocated (avail for LUNs) = 10879 MB *
-----------------------------------------

It looked some of space used for redundancy plus big part of the 18GB space was converted to active hot spare (34732 MB, the size of the largest disk in our array). The space used for redundancy is decreased, is this a bad thing?

I assume it is OK now unless you told me something is wrong?

Thanks,


Jane