VA7100 (autoraid to raid 1+0)

[Vincent Abad]

Hello,

We have a VA7100 with LUN created with AutoRaid flavor.
The amount of space available on the VA is very
thin, metrics reports that all datas are stored
in RAID5DP mode, with such a mode, Oracle Write
performance are drastically degraded.
If we free a maximum space, is there a way to force the VA, to balance data to RAID1+0 mode (still using AutoRaid flavor)(indeed changing array RAID control mode not possible after LUN creations).

Thanks in advance,

--Vincent

[Vincent Fleming]

Vincent,

If you free up 1/2 of your total raw space (ie: you have 500GB raw, then have no more than 250GB assigned to hosts), then it will all migrate to RAID 0/1.

Good luck,

Vince

[Eugeny Brychkov]

Vince,
to help you I need 'armdsp -a' and 'armlog -e' outputs. Please attach them to your next reply zipped.
Please tell where did you see that everything is in RAID5DP mode - did you use armperf?
Eugeny

[Vincent Abad]

Hello Vince & Eugeny,

Thanks for your response.
Here is my current configuration:
Redundancy Group:_____________________1
Total Disks:________________________15
Total Physical Size:________________417.232 GB
Allocated to Regular LUNs:__________125.02 GB
Allocated as Business Copies:_______0 bytes
Used as Active Hot Spare:___________33.375 GB
Used for Redundancy:________________93.818 GB
Unallocated (Available for LUNs):___165.018 GB

We have free up a lot of space, but it seems that the optimization (RAID5->RAID1+0) is very slow (only 10% for a average of 24h).Is their a way to accelerate the transfert.
Eugeny, find attached the arm files.
we use both armperf, and launcher GUI for measuring RAID allocation.

Thanks,

--Vincent

[Eugeny Brychkov]

To accelerate the process leave VA alone - do not access its LUNs for some time
Eugeny

[Eugeny Brychkov]

The answer to your question is in VA log. There was a rebuild recently, and after rebuild VA moves all data into RAID5DP. So now optimization process will take place, and please be patient and do not access array (badly) and optimization will complete soon
Eugeny

[Roger_22 · Accepted solution]

The total LUN allocated capacity should be below 121GB (per Command View) and active hot spare set to 0, for this array to convert to RAID 1+0 only operation.

(Eugeny, I sent you the code to compute this???..)

Until the array has converted the data to RAID 1+0, the array can run significantly slower. This because the array will not perform log-structured RAID 5DP writes ??? which can be very performance efficient.

Use the armperf ARRAY command. This will show the RAID 1+0 and RAID 5DP allocations over time.

I also suggest that you enable prefetch (armmgr ???P on).

I don???t think the rebuild had much effect. It looks like you were moving/adding disks or reset the controller? If not, you should have hp support review the logs.

[Vincent Abad]

Hello Eugeny and Roger,

Thanks for your response.
Roger, are you roger buckthal?
How does you calculate the allocated capacity of 121GB to convert to RAID 1+0 only operation in our case.
You could send me your response,if you want, to following mail address:
vincent.abad@hp.com

Thanks in advance,


--Vincent