On Tue, 2004-07-20 at 14:23, Eugene Chu wrote:
As a side note, the RAIDing functions of the Escalade cards are all done by their kernel drivers. Therefore, if you use a parity based RAID, like level 3 or level 5, you will be sucking down your CPU as you use those disks. I have mine configured in RAID 1+0, to get greater capacity, speed, and 100% redundancy.
Hmm. I am pretty sure that the 3ware cards are hardware based parity. http://www.3ware.com/products/serial_ata.asp If you are seeing high CPU utilization, it could easily be something else. We have built/used a number of server systems for customers based on them, and do not see CPU-"sucking" for large raid-5 systems under heavy load. If you are constantly remapping bad sectors, or rebuilding the array, you might see some load, but not significant amounts. Some of the Linux journaling file systems have performance issues under intense load, specifically in their journaling code pathways. This shows up as system time being a significant fraction of a runtime for an intense IO job. Joe -- Joseph Landman, Ph.D Scalable Informatics LLC, email: landman@scalableinformatics.com web : http://scalableinformatics.com phone: +1 734 612 4615