Disk Arrays
cancel
Showing results for 
Search instead for 
Did you mean: 

EVA 4000 and Integrity Rx2620 with SQL as DB

Satish Kumar_5
Regular Advisor

EVA 4000 and Integrity Rx2620 with SQL as DB

Hi All,

We are running a customise application with SQL as backend database on HP DL 380 servers with 2 GB RAM. It was running perfectly fine. Then due to in some reports time taken was too long we went for the upgraded h/w. Now we have 2 HP Integrity RX2620 with EVA 4000 and 2 SAN switched connnected in NSPoF. We have done a SQL DB cluster on same. Now our CPU utilization on our Active server remains around 100% irrespective of whatever server becomes active. We called Microsoft chaps and they come up with some ISSUE in SAN. Then we contacted HP support and they asked for some logs. After working on the logs for around 10 days or so, which i thought very pathetic of HP solution center, they told us that our application is generating around 2500 I/Os which EVA is not able to handle. We are really in a hole now as our users are experiencing a very slow responce and management is after us to get this sorted out. We have 8 FC 146 GB 10K RPM disk with one shelf in EVA. Our database size is around 100 GB. We have our DB in VRAID5 in EVA. My queries are:

1. Is 2500 I/Os are really bottleneck on EVA 4K. I checked on HP site and its around 1,41,000 for same.
2. Is there something wrong with SQL whcih is causing this. Even microsoft people checked it and said its OK.
3. Is there a way to get out of this hole?

Any help will be really appreciated as we are very stressed for past 20 days and HP and Microsoft are playing ball game.

Thanks all for their valuable time.
7 REPLIES
Uwe Zessin
Honored Contributor

Re: EVA 4000 and Integrity Rx2620 with SQL as DB

141,000 IOPS is an unrealistic value that you will never see in real world applications.


I don't know where your bottleneck is, but you have only 8 disk drives:
141,000 / 8 = 17,625

do you really think you can get 17,625 IOPS from a single disk drive???


2500 IOPS / 8 disk = 312 IOPS per disk

even that is an impressive value for a single disk, but I'd say you have some data locality and don't use full strokes.


IF you environment is constraint by IOs, then you need to get more disk drives.
.
pswma2
Frequent Advisor

Re: EVA 4000 and Integrity Rx2620 with SQL as DB

Hi,

if you have some disk space free in this EVA-4000 (with 8 disks you should have nearly 800 GB total capacity), create new virtual disks with Raid-1.This would reduce internal load of the HSV-200 controllers, bcs. Raid-5 needs 2 reads for each write operation.You can see this in the output of "evaperf hps" on your storage management server.
2. when you create these new virtual disks put the preferred path/mode of vdisks for database and transaction log to different values, like "Path A-Failover only" and "Path B-Failover only". This trick brings HSV-controller in most cases to put new vdisks on different managing controller: Controller A and B.
3. After two previuos steps you will be able to say whether your transaction log or database generates 2500 I/Os. As far as I know the FC 10K rpm disk can do 90 I/O per second, FC 15K rpm - 125 I/Os. Suppose SQL transaction log needs 1800 I/O per second, so 1800/90=20 disks (at least) are required to process this load.
Satish Kumar_5
Regular Advisor

Re: EVA 4000 and Integrity Rx2620 with SQL as DB

Hi PS,

What u said made lot of sense. but the problem is our management wont let us buy more h/w.On top of this, we never faced this issue earlier when our DB was running on DL 380 local HDDs in RAID5. So how come all of sudden this much IOs? Can we know by some utilty why so much ios?

Thanks again for your time.
kris rombauts
Honored Contributor

Re: EVA 4000 and Integrity Rx2620 with SQL as DB

Here is a usefull whitepaper, it is primarily for the cell based/partitionable Integrity systems but the storage part is still applicable regarding I/O's and type of driver (storport uses less CPU resources). Pls have a read and make sure you do use the Storport drivers for your Fibre Channel adapters in the hosts.

Also some LAN interfaces allow to do CPU offloading.

http://docs.hp.com/en/8875/WIE-SQLTuning-1006-00.pdf


HTH

Kris
Satish Kumar_5
Regular Advisor

Re: EVA 4000 and Integrity Rx2620 with SQL as DB

Hi Chris,

Thanks for the DOC. I will definately read it and try to find something. In the meanwhile let me give u the update. Just to eliminate suspects, we put our database server on a DL 380 G4 again with EVA as storage.This setup is giving us the performance which we were getting earlier. The database is SQL 2005 ent 32 bit edition.Now this clearly means that Itanium is sole culprit. The CPU utilisation on DL is around 60-70% where as in Itanium it remains 100% all the time.As per microsoft support, some queries are hitting CPU directly rather than CPU cache which is causing more CPU utilisation.We are really in a hole as both HP and Microsoft say that Itanium on sql 2k5 gives better performace but what we are seeing is totally opposite.Now we really thought that a better DL server with more CPU and RAM culd have done it for us rather than spending on Itanium.Do anybody else also faced this kind of issue.

Any help will be really appreciated.
Duncan Edmonstone
Honored Contributor

Re: EVA 4000 and Integrity Rx2620 with SQL as DB

Satish,

Stupid question I know, but you *have* installed the 64-bit IA64 version of SQL Server on the rx2620 haven't you? Not the 32-bit x86 version? If this was installed it would have to run in x86 emulation mode and would be slow and use a lot of CPU...

HTH

Duncan

HTH

Duncan
Satish Kumar_5
Regular Advisor

Re: EVA 4000 and Integrity Rx2620 with SQL as DB

Hi Duncan,

Ofcource we have installed 64-bit SQL 2k5 only.This is really strange and i am not able to find out why on Integrity utilization is 100%, even after being a superior platform as per both microsoft and HP.