Performance Problem with netraid-2M, tc4100 RS12

[Ing. Carlos Mejia]

I have configured an HP TC4100 with a NetRAID-2M card and 4x36Gb HP disks in RAID 5 under SCO Openserver 5.0.5 with all patches needed to function correctly. And the last firmware version. The HP TC4100 is in cluster with other server tc4100 and the Rack Storage 12.

The system function well, but there is something wrong with the performances : I nedd 1 hour to transfer a 6 GBytes from a filesystem to another

Any suggestion ?


Thanks


Carlos Mej??a

[Erwin Zoer]

Hello Carlos,


I would suggest you try to figure out where the bottleneck is by using an application such as IOZone (www.iozone.org). Using this application I would suggest you try to find out where the bottleneck is by trying to find the maximum performance for each component involved in the file transfer:

- read performance (read to nul device)
- write performance (write from mem to fs)
- network connectivity?

I hope this helps.


Erwin

[Brian Peters]

Hello Carlos,

Since this is a large file transfer, I would recommend trying to change the I/O cache policy of your logical drive to "Direct I/O" in Netraid Express Tools (cntrl -m). At the same time change the write policy to "Writethru".

The previous policies (cached I/O and Writeback) are really good for small and repetitive transfers because the cache already have the information stored for a quicker access. On large tranfers, the cache has to be flush constantly so it can store new information before it cache "writesback" to the disk. This can result in a noticable overall slow transfer speeds of large files.

Of course, take the necessary precautions for a cluster enviroment.

Hopefully this is helpful.

[Christian Schmidt · Accepted solution]

Hello,

there was a known problem with the amird-driver 2.13-11 and the monitor-utility.
Performance was very bad.

I disabled the monitor amirdmon in /etc/conf/rc.d/amird --> then performance was good.

Then you could set the write-policy to write back !!! --> but you must have a good UPS !!

Regards

Christian