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Re: VA7400 Performance

 
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Thomas Maddox
Advisor

VA7400 Performance

I have a possible performance on a VA7400. When disk queues are high, users connecting to our Oracle 8i database through a web based Java Application get disconnected. Also, jobs running on other systems are slow.

I have 2.1TB usable on my VA7400 and over 3TB of data is read and written to and from the SAN most any day. We get sustained disk queuing on LUNS that are primarily writing. The disk queues show a queue legnth of over 100 for days in Galnce, Perfview, and SAR. My Oracle database is 120 GB.

We have a VA7400 that is connected via fibre to 2 Brocade Switches. Two
rp7400s, four rp2470's, one L2000, one Windows 2000 server, and an 4/40 LTO
tape library are connected to the two Brocade Switches.

It seems odd that the queue legnth stays consistant over a long time frame. It
also seems odd that the queue legnth does not clear.

We upgraded the VA7400 to firmware 17 and installed the latest patches in December 2002.

When are reads and writes excessive in a VA7400?
How can we determine it this is a true measure of this LUN's performance?

26 REPLIES 26
Eugeny Brychkov
Honored Contributor

Re: VA7400 Performance

Tomas,
what to check:
- everything is in fabric (looking to brocades' switchshow output you see onyl F-ports);
- you assigned VA LUNs PVs primary paths through their perfomance path. For LUNs created within RG1 perfomance path goes through VA controller C1 and for LUNs within RG2 through C2;
- you have no hardware problems with VA (armlods -e);
- you have VA in ready state (armdsp -a);
- tune queue depths for VA LUNs 'scsictl -m queue_depth=16 /dev/rdsk/c5t0d0', this value should be 3*number of disks in RG. Max 240 per array.
Attach these here zipped (supportshow from both brocades, armlog -e and armdsp -a)
Eugeny
Thomas Maddox
Advisor

Re: VA7400 Performance

In the armlog I get several messages:
Event Type: Controller Event
Event Code: 348
Severity: 1
Event Description = FRONTEND_FC_ABTS_EVENT_EH This error code indicates that the Host sent a Fibre Channel ABTS (Abort Sequence) BLS frame to the abort an IO. The array will log this event for informational and debug purposes only. It does not necessarily indicate a problem with the array.
Brian M Rawlings
Honored Contributor

Re: VA7400 Performance

Thomas: the VA7400 is a fine array, who's strengths are easy administration and easy expansion, but which is not well suited to the massive I/O performance you appear to be hitting it with.

I suggest that users trying to connect are actually timing out, since this array can't "drop users" itself.

My suggestion would be that, for the kind of multi-server load and extreme I/O you are talking about, you need a much faster array, such as the EMC Clariion CX600 (current hot box this week). Not what you wanted to hear, but I can't imagine how else your array is causing users to drop or to fail to connect.

The VA7400 performs best with extra unused storage, and several drawers full of disks to spread the I/Os across. If you only have one disk tray, I'd see about getting another. When you have lots of free space, the VA7400 will try to store everything as RAID-1/0, mirrored, for fastest access. But it can only do so much. In the design, a tradeoff was made for easy self-management of data, at a sacrifice of performance (for most data patterns). It sounds like you've buried it, now all you need is a headstone.

Good Luck, I'm afraid you'll need it until you can upgrade to something that can handle this large workload.

--bmr
We must indeed all hang together, or, most assuredly, we shall all hang separately. (Benjamin Franklin)
Roger_22
Trusted Contributor

Re: VA7400 Performance

attach the output from the command. I look at it ....

In general, you have a lot of cpu power on a single array.
Eugeny Brychkov
Honored Contributor

Re: VA7400 Performance

Thomas,
in addition to what Roger asked you to attach please post driver your windows2000 server is running for FC HBA. Old Agilent driver 3.0.4107 had a timeout bug, and it's recommended to upgrade driver to the current Adaptec 2.0.25.44 downloadable from http://h20004.www2.hp.com/keeper_rnotes/bsdmatrix/matrix213991.html
Eugeny
Thomas Maddox
Advisor

Re: VA7400 Performance

The armdiag command hangs on vgdisplay -v.
The old Agilent driver is not relevant for this server, because we do not use that card.
Roger_22
Trusted Contributor

Re: VA7400 Performance

try this script. copy to the command view/client/bin directory. getvalogs.
Roger_22
Trusted Contributor

Re: VA7400 Performance

if you have problems with that, i just need the output of the following commands:

armdsp -a
logprn -t all -v -s -a
armperf -c ARRAY -x COMMA -s
armperf -c OPAQUE -x COMMA -s
armperf -c LUN -x COMMA -s
armperf -c DISK -x COMMA -s


see the manpages for the format of the start time. give me 2 weeks of data. sorry for the hassle, but you'll like what i send back.
Roger_22
Trusted Contributor

Re: VA7400 Performance

one more thing, zip/tar them up, they can be large.....