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Sluggish disk volumes

 
Per Kr. Meyer
Occasional Advisor

Sluggish disk volumes

Server: DL380 G2 (1,3 MHz)
Disk: 6 x 36GB, 1 HotSpare, RAID5, 2 logical volumes, NTFS, Win2000srv SP4.
Example 1: it takes about 5 minutes to delete a 9GB MSSQL .BAK file.
Example 2. I've got a compressed, and indexed directory with aprox 640 sub-dirs with some 2.000.000 small xml-files making up about 10GB of diskspace (15GB free). It's not possible to look at this dir in "explorer" - it times out. When opening properties for this directory, the server uses over an hour to calculate the size and numbers.
Is it the compressing or the indexing or something else that causes this sluggishness ?
How to tell ?
14 REPLIES
Per Kr. Meyer
Occasional Advisor

Re: Sluggish disk volumes

By the way, this server is a MSSQL server and has 1.5GB of RAM. Embedded Raid controller is Smart Array 5i, with battery backup.
Interface : 64bit bus
Hardware rev : B
Firmware ver : 2.20
I ran ADU, and it didn't reveal any errors.
Report attached.
How can I tell wether writecache is enabeled ? ACU-controller-info shows that controller cache (64MB)is devided equally between write and read.
Ryan Goff
Valued Contributor

Re: Sluggish disk volumes

what is the stripe size on the raid 5 array?
Igor Karasik
Honored Contributor

Re: Sluggish disk volumes

I am afraid it is normal Windows behaviour and not related to server.
We have 6 servers running Filenet application (imaging and document management) on windows 2000.
Our servers is ML370 G4 with dual CPU and 4 Gb RAM, 6400/128 RAID controller. Data stored on RAID-5 volume.
Data consist more than 5.000.000 files divided by 50.000 files in folder.
We never works with these folders with windows explorer (it just stucks), we only use vbs script to calculate number of files/size in each folder.
We not use "compess drive" option in Explorer.
Regards, Igor
Per Kr. Meyer
Occasional Advisor

Re: Sluggish disk volumes

Stripe size ?
Gee, I don't know. Used default values all the way during installation.
Opening a xml-file when I apply full path, is quick enough. Explorer seems unable to cope with directories of this size. Igor says this is normal Explorer behaiviour. Unless somebody have another clew, I'll probably have to live with it.
By the way : Can somebode tell me how to calculate the sufficinet amount of RAM this server needs ?
It runs a 9GB database on MSSQL2000srv.
Igor Karasik
Honored Contributor

Re: Sluggish disk volumes

There are no common rule for calculating RAM on SQL server. It depends on what kind of data is being stored (DSS vs OLTP), how much activity is expected on the system,.....
Try to use performance monitor and see where you have bottleneck. You have 1,3 MHz CPU, maybe it will be your bottleneck before memory.
You can also look into HP tools:
"HP ProLiant Data Mart Sizer for Microsoft SQL Server 2000" and
"HP ProLiant Transaction Processing Sizer for Microsoft SQL Server 2000"
http://h71019.www7.hp.com/ActiveAnswers/cache/70728-0-0-225-121.html#300
(You need HP passport in order to use these tools)
http://h71019.www7.hp.com/ActiveAnswers/cache/70728-0-0-225-121.html#300

Regards, Igor


Ryan Goff
Valued Contributor

Re: Sluggish disk volumes

5i controller is known to sometimes set the incorrect stripe size of 16k on raid 5 instead of 64k which can cause performance degredation. You should be able to check stripe size within the array configuration utility.

Have you run all firmware updates?

This CD will update everything:

Firmware CD 7.4:
http://h18007.www1.hp.com/support/files/server/us/download/23331.html
Per Kr. Meyer
Occasional Advisor

Re: Sluggish disk volumes

Stripe size is a value that should be extracted in a ADU report, wouldn't you say? I have ran ADU and searched the report. A value for Stripe size isn't there.
I will find the time to do a firmware upgrade. This hasn't been done for the couple of last years.
How do the 5i controller compare with other RAID controllers ?
Which is the best RAID-controller for a DL380 G2 ?
Igor Karasik
Honored Contributor

Re: Sluggish disk volumes

To determine stripe size:
Open Start Menu\Programs\HP System Tools\HP Array Configuration Utility program group and open "HP Array Configuration Utility".
Select your Logical drive and choose "More information" in select tasks window.
You will see Stripe size in "More information" window
Regarding 5i controller:
http://h18004.www1.hp.com/products/servers/proliantstorage/arraycontrollers/feature.html
5i doesn't have Battery Backed Cache, it means doesn't have write cache.
But maybe you have 5i plus, it has Battery Backed Cache.
Anyway, there are no "best controller", it depends what you need. As I wrote before we have same behaviour on much more powerful server with strongest SmartArray controller
Per Kr. Meyer
Occasional Advisor

Re: Sluggish disk volumes

Yet another thing:
1.I've got the batterybackup addon feature in place for the 5i controller. Write cache could now be enabled with small (or no) chanche for data corruption due to powerloss or other critical failiure - right?
2.The server currently holds 1.5GB RAM. The Database is 9GB.
The sqlsrv.exe process has a lot of Page faults.
Windows Task Manager, Page faults - this value indicates disk-swapping, right ?
Add memory ?
Per Kr. Meyer
Occasional Advisor

Re: Sluggish disk volumes

Yess, the stripe size is 16k.
I can't alter this without rebuilding the RAID from scratch.
To what extent will this fact impact performance ?
Stripesize 16k vs 64k
Per Kr. Meyer
Occasional Advisor

Re: Sluggish disk volumes

And by the way :
The RAID controller says it's a SMART RAID 5i. No "plus". Yet it states that cache memory is equally devided between read and write (24576KB on each). It says battery pack count 1 and battery status ok. Should be safe to enable write cache, or..... ?
Ryan Goff
Valued Contributor

Re: Sluggish disk volumes

Ok, so it seems I was right about your stripe size. Your 5i controller defaulted to 16k size for your Raid 5 when you installed the server. HP has changed this default value on the newer controllers as they have found that it performs better at a 64k value.

You can easily migrate to 64k stripe size and I definately recommend this to speed up your performance.

You will want to take some steps before doing this though.

1) Run firmware updates from the Firmware CD that is Link'd above.
2) Install Proliant Support Pack 7.4 for Windows 2000:
http://h18007.www1.hp.com/support/files/server/us/download/22870.html
3) ***GET A KNOWN GOOD BACKUP***
4) The only last thing that I can recommend is to run the Array Diagnostics off Smartstart and post the results file here after running firmware updates so that we can check to make sure there are no errors on any of your drives first. If you start a migration when there are errors on the drives the migration may fail. Your system does not always warn you of potential errors on the drives and would be a good safety measure.

This is not a fast procedure by any means, but it can be done online and should not cause that much of a performance hit on the server while it is running.

If you would like documentation on why you should switch to 64k stripe size, read this PDF on page 2, was all I could find for now:

http://h200005.www2.hp.com/bc/docs/support/SupportManual/c00366606/c00366606.pdf

Now, as for your BBWC, if you allready have 50/50 for read/write you dont have to enable write caching as it is allrady doing it at the hardware level, but it would not hurt to enable it in software side to see if it helps at all for testing purposes.
Igor Karasik
Honored Contributor

Re: Sluggish disk volumes

If you have battery pack you can enable write cache, it is safe.
Regarding stripe size:
there is no common rule.
It depends what number of disks you have in RAID-5, if your application write or read
intensive,....
Generally speaking if you have application with many small files stripe size 16K maybe better for your vs stripe size 64K.
Ryan Goff
Valued Contributor

Re: Sluggish disk volumes

Sorry I forgot to add in steps on how to migrate.

With the array configuration utility open, click the logical drive you want to change, then select the option on the right to migrate raid/stripe. From there you can modify the stripe size to 64k and apply that and save changes to start the process.

You can also get a progress bar by going to the properties of that logical drive to see how far along the process has gone once you save changes.