DSS FC write problems

[Robotbeat]

Are you using the "default" blocksize when you format the drives as ntfs? When I tested FC volumes with different blocksizes set on the DSS interface, I manually set the blocksize in windows as I was formatting them as ntfs. This was also with windows 2003. Have you done anything like that?

[hughesmikea]

I did format with default. Just now talking with Todd, I reformated with 512 and 4096 and got the same bursty respone on writes.

[symm]

HI hughesmikea

Your Qlogic 5600 switch settings are they set to auto?
If so set them manually.

[hughesmikea]

I changed the switch ports for DSS from auto negotiate to 4GB. No difference. I/O guard is set to auto.

I did not change the ports for Xen, because I do not have this issues from Xen to SANmelody on the same switches.

thanks
mike

[symm]

Hi hughesmikea

What RAID level are you using?
Can you try enabling cache and read ahead on your RAID controller.
how much RAM do you have ?
Is it locking up or is the write fast in the beggining and then slowing down?

[Robotbeat]

Have you compared it to iscsi or nas performance on the same disks/dss?

[hughesmikea]

gentlemen,

Server is a brand new PowerEdge 2970 with a PERC 5/i RAID controller and 4GB RAM
(6) 1TB SAS Drives in a RAID 5 with writeback cache enabled (default)

Just created an iSCSI volume and attached my PC to it. I copied a 2.5GB file across smoothly.

When copying acrosss FC, the copy has an initial burst, then pauses for a while, then bursts again, then repeats until complete.

mike