VA7400 performance

[Domenico Viggiani]

I have a VA7400 array connected to a RP7400 by two Brocade switches.
The system is esentially an Oracle machine.
Using Glance, I can see low CPU utilization (20-60%) but frequent disk bottlenecks (i.e high system load).
I already read forum postings and HP docs about performance issues, I put array in High Performance mode, LUNs in RG1 use Controller 1 as primary path (and viceversa), etc.
Using CommandView metrics, I can see a Total I/O throughput lower than 40 units/sec.

Do you think that putting all Oracle file on the same, big LUN can cause this performance issues?
A firmware upgrade (actually I have HP13) can also be useful?
Other suggestions?

[Marino Meloni_1]

Hi
I can said you that the last release of FW could for sure solve some performance issues

bye

marino

[Peter Mattei · Accepted solution]

How many disks are in the array, what type? The VA7400 performs best with >45 disks installed!
What mode are you running?
AutoRaid or RAID01?
If AutoRaid, what is the R01/R5DP ratio?
For OLTP and high write IO rate Raid01 performs much better. This is not an error just normal RAID5 behaviour (RAID5 write penalty).

Peter

[Leif Halvarsson_2]

Hi
I dont think using one or more LUNs make any performance difference.

If you suspect bad file system performance you can use the postmark benchmark (attached) for checking.
Compile it (cc postmark.c).
Rename the output file (mv a.out postmark).
Move the file to a directory on the filesystem you want to test (mv postmark /xxx/yyy/zzz)
Start postmark (./postmark)
At the pm> prompt:
Set parameters (pm> set number 30000, pm> set transactions 5000)
You can test with different values.
Run the test (pm> run)

Here is the output from my RAID system.

Time:
147 seconds total
34 seconds of transactions (147 per second)

Files:
32453 created (220 per second)
Creation alone: 30000 files (384 per second)
Mixed with transactions: 2453 files (72 per second)
2532 read (74 per second)
2468 appended (72 per second)
32453 deleted (220 per second)
Deletion alone: 29906 files (854 per second)
Mixed with transactions: 2547 files (74 per second)

Data:
12.67 megabytes read (88.24 kilobytes per second)
167.31 megabytes written (1.14 megabytes per second)

With a VA 7400 I think you will get better performance then me.

[Steve Lewis]

I think you should put your rollback segments on a 2nd LUN, also put one set of control files on this 2nd LUN.
Some people recommend putting indexes in a separate LUN from data, you might try this but I think it depends on your own experience of the application and tablespace usage. For instance if you have a high i/o tablespace then it may be worth moving it away from the others.
Route the traffic to this 2nd LUN through the other switch.

I personally like to keep about 4 LUNS for Oracle and I have noticed that it does seem allocate separate LUNS to separate disks, so it does make a difference.

Make sure that your waits are Oracle i/o based and not caused by semaphores or (even worse) memory paging.

[Domenico Viggiani]

I read also other messaages about VA7100, all suggesting the upgrade to HP16 firmware.

Actually array has 14*3=42 disks (36 GB) but installation of others 2*15 = 30 disks (72 GB) is in progress.

Array is configured in AutoRAID mode (I don't know R01/R5DP ratio).

I will try to run postmark benchmark next week. Thank you very much, Leif!

[Domenico Viggiani]

These are my numbers:

Time:
355 seconds total
146 seconds of transactions (34 per second)

Files:
32453 created (91 per second)
Creation alone: 30000 files (212 per second)
Mixed with transactions: 2453 files (16 per second)
2532 read (17 per second)
2468 appended (16 per second)
32453 deleted (91 per second)
Deletion alone: 29906 files (439 per second)
Mixed with transactions: 2547 files (17 per second)

Data:
12.67 megabytes read (36.54 kilobytes per second)
167.31 megabytes written (482.60 kilobytes per second)

Very Bad.

[Leif Halvarsson_2]

Hi
I agree, there must be something wrong, perhaps firmware upgrading will help.

My test was from a CMD 7400 RAID controller and a RAID 5 set with only 4 drives. A VA7400 should perform much better.

[Domenico Viggiani]

These are results after upgrade to HP16:

Time:
164 seconds total
66 seconds of transactions (75 per second)

Files:
32453 created (197 per second)
Creation alone: 30000 files (535 per second)
Mixed with transactions: 2453 files (37 per second)
2532 read (38 per second)
2468 appended (37 per second)
32453 deleted (197 per second)
Deletion alone: 29906 files (712 per second)
Mixed with transactions: 2547 files (38 per second)

Data:
12.67 megabytes read (79.09 kilobytes per second)
167.31 megabytes written (1.02 megabytes per second)

[Genta Paola]

Hi Domenico,
I've seen some of your notes about troubles with VA7400. We 're evalueting of buying this storage system: would you mind having a private talk about its availability and performance? My address is pgenta@ferraniait.com

Thanks
Paola Genta