Raid 5 slow sequential write speed

Check the status of the array and make sure it is not in a degraded state.  You should also run diagnostics on each drive from the controller, to see if any are failing.  Try another cable as well, check if the SCSI ids are correctly jumpered for all devices, and make sure the termination is set properly (one on each end of the cable, either electronically or otherwise).

I ran an Array Diagnostic utility.  Id did not report any errors with the array.  It did however, report a sector size of 512 bytes, however, I had changed it, and chkdsk reports 4096 bytes.  Can this be related to the slowness.

I will check the cabling later.

Thanks

I've never tried a sector size other than 512; was there a reason you changed it?

The benchmark will report a 10x slowness when it is (1) checking the raid for consistency, (2) writing the checksums, (3) refeshing the RAID redundancy, (4) have a driver that is not compatible with the OS, or (5) having sector read issues.  You should continue to test the array, and if the situation does not improve in a day or so, you should look at the drives in windows, make sure the RAID drivers are OK.  And if you continue to get problems, as long as there is no data lost or missing, run checkdisk.  If it still does not improve performance, look and upgrading the RAID BIOS from the HP website.  And if all that fails, you probably have a failing disk which is causing repeated reads.  Do you hear clicking from the drives?  If so, one is haing sector read errors, so it is time to replace it.  This RAID should do 65Mb ++.

I noticed that through the device manager in control panel, wrte caching is not enabled.  Could this be causing the slowness.

By the way there really is slowness - it noticed it before running the diagnostic utility.

Write caching is in the controller, and you should still see good results on reads.  I would say take apart the array and test the performance with each drive separately.

Have you looked at which way the cache is oriented? read vs write. Is this a 5i or a 5300 controller?

Mike

Thanks,

I noticed before your post that windows does not allow me to enable write caching.  I'll purchase the HP 128MB BBWC.  If this allows me to enable toe wriote caching, and it greatly improves the sequential write speed, I will give you the points.

It worked!

I bought the HP 128MB BBWC and configured write caching.  I now get a benchmark speed of over 56.


Thanks

Mhalp200,
Did you have to back up & restore to replace card, I have the same problem write 9mb/s read 111mb/s
with perc4/sc
SCSI is hard to image and restore