----- Original Message ----- From: "Eric Anderson" <[EMAIL PROTECTED]>
Where do I start looking?
First, understand that RAID 5 is dependant on fast hardware to performa the XOR operations. A single disk without any RAID can easily outperform a RAID array if the RAID array is on a 'slow' controller. The Highpoint controllers are not exactly high-end fast RAID controllers, so ~50MB/s isn't too bad for that I would say. Did you happen to try a vinum RAID5? How about a stripe?
The quoted benchmarks for this controller are ~500MB/s with 8 raptor disks. Its a hardware RAID 5 with 8 SATA channels on 64Bit PCI-X
@ 133Mhz so under the current setup it should be achieving ~250MB/s
Im only getting 50MB/s which is just silly.
It was also my inderstanding that the XOR is only done on write not read.
Correct - I misread the dd line. When you are doing the dd, what is your system busy doing? (top/ps info)
You could make two RAID 5's with the controller, and then stripe those in vinum. You could also do a combo of two stripes in the controller, and a vinum mirror in FreeBSD - that would give you decent performance.
I could but it seems there is something more problematic a foot here and would like to investigate the reason for the poor performance not workaround it.
What do you suspect?
Some info from one of my arrays:
# dd if=/dev/zero of=./testfile bs=64k count=10000 10000+0 records in 10000+0 records out 655360000 bytes transferred in 3.581413 secs (182989226 bytes/sec)
(unmount / mount filesystem) # dd if=./testfile of=/dev/null bs=64k count=10000 10000+0 records in 10000+0 records out 655360000 bytes transferred in 6.747707 secs (97123362 bytes/sec)
# dd if=/dev/da0s1d of=/dev/null bs=64k count=10000 10000+0 records in 10000+0 records out 655360000 bytes transferred in 11.252226 secs (58242699 bytes/sec)
Seems like the reads should be faster than the writes..
Eric
-- ------------------------------------------------------------------------ Eric Anderson Sr. Systems Administrator Centaur Technology A lost ounce of gold may be found, a lost moment of time never. ------------------------------------------------------------------------ _______________________________________________ freebsd-performance@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-performance To unsubscribe, send any mail to "[EMAIL PROTECTED]"
