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DL 380 G5 RAID 5 Slow

 
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Chris Camm
Advisor

DL 380 G5 RAID 5 Slow

I have a DL 380 G5 with P400 controller.

Disks 1 and 2 are in RAID0+1
Disks 2-8 are in RAID 5

The disks are all 68GB SAS 15Krpm

Reading and writing to the RAID 0+1 array is very quick.

Reading from the RAID 5 is very slow, writing even slower.

This problem was not there on the same setup on a DL 380 G4 with four disks in the RAID 5 array. It is also not there on any of my other DL380 G5 Server with a P400 Controller and only four disks in the RAID5 array.

The array cache is set to 100% read and 0% write.

I have the latest firmware patches on the server, raid controller and disks. The latest SSD's are installed too.

Any ideas greatly appreciated.
28 REPLIES 28
juan quesada
Respected Contributor

Re: DL 380 G5 RAID 5 Slow

RAID 5
Advantages:
├в ┬в Has high read performance.
├в ┬в Data is not lost if one physical drive fails.
├в ┬в More drive capacity is usable than with RAID 1+0├в parity information requires only the storage
space equivalent to one physical drive.
Disadvantages:
├в ┬в Has relatively low write performance.
├в ┬в Data is lost if a second drive fails before data from the first failed drive is rebuilt.

http://bizsupport.austin.hp.com/bc/docs/support/SupportManual/c00729544/c00729544.pdf

The behavior you have is odd, can you run and ADU (array diagnostic utility) report and attach it?

Regards
Chris Camm
Advisor

Re: DL 380 G5 RAID 5 Slow

Please find attached the ARU report

Thanks
juan quesada
Respected Contributor

Re: DL 380 G5 RAID 5 Slow

Hi,

the Image is broke.

*.zip file must have an *.txt file inside.

regards
Chris Camm
Advisor

Re: DL 380 G5 RAID 5 Slow

Very sorry.

Here is the txt file

Regards

Chris
juan quesada
Respected Contributor

Re: DL 380 G5 RAID 5 Slow

ADU is OK. storage subsystem is fine.

If you have w2k3 updating the Smart Array P400 driver to revision 6.6.2.32 improves performance to expected levels.

If w2k there is no solution as a new driver to resolve the issue.

As a workaround:
The write caching can be disabled by setting the Read/Write ratio to 100/0 on the logical drive being utilized
Chris Camm
Advisor

Re: DL 380 G5 RAID 5 Slow

I am currently running with 6.8.0.32 I will downgrade and see what happens.

Thanks
Mi6t0
Trusted Contributor

Re: DL 380 G5 RAID 5 Slow

Try with the newest driver for p400 (6.10.x.x).

About the read/write priority - you don't have a cache module,so it is just an automatic setting. With cache module you may feel better performance and you will be able to edit the read/write prio.

Kind regards,

KarloChacon
Honored Contributor

Re: DL 380 G5 RAID 5 Slow

fi the recommendations above dont work:
latest driver / disable cache

getting an BBWC update would be the only
solution in case you have 256 MB BBWC right now

regards
Didn't your momma teach you to say thanks!
juan quesada
Respected Contributor

Re: DL 380 G5 RAID 5 Slow

customer have 512

Total Memory Size 512 MBytes