In one of my servers, there is a 3-drive RAID 5 built on a LSI 320-1 U320 SCSI Raid Controller. There are 3 36GB, 10Krpm, U320 drives on it. I had all of the caching, read-ahead, etc, disabled in the interest of data integrity.
While on the phone with the LSI technician, we ran 10MB FTP benchmarks on the array, getting a max read speed of about 72,000KBs (72MBs), which with these settings is reasonable for a RAID 5 with only 3 drives. But, the write speeds are like 6,000KBs (6MBs)!!
I enabled the I/O caching,and the read-ahead, and the read speeds rose to 110,000KBs. Nice, but there was no change to the write speeds at all.
The LSI tech acknowledged that the write speeds are 1/3 to 1/2 of what they should be (even with the drives set to write-thu, again, for data integrity), but was unable to offer any assistance.
Any information that sheds light on this situation would be greatly apprediated!
Thank you for your time.
While on the phone with the LSI technician, we ran 10MB FTP benchmarks on the array, getting a max read speed of about 72,000KBs (72MBs), which with these settings is reasonable for a RAID 5 with only 3 drives. But, the write speeds are like 6,000KBs (6MBs)!!
I enabled the I/O caching,and the read-ahead, and the read speeds rose to 110,000KBs. Nice, but there was no change to the write speeds at all.
The LSI tech acknowledged that the write speeds are 1/3 to 1/2 of what they should be (even with the drives set to write-thu, again, for data integrity), but was unable to offer any assistance.
Any information that sheds light on this situation would be greatly apprediated!
Thank you for your time.
