I'm experiencing poor disk i/o performance on a Dell C6100 with a SAS1068E. Running stock CentOS 6.5 with all the latest updates
/dev/sda is a 4 disk IME array of 15k sas seagate ST9146852SS drives
/dev/sdb is a 2 disk IM array of 2 Samsung 840 Pro SSD drives
I'm using sysbench to test: sysbench --num-threads=16 --test=fileio --file-total-size=3G --file-test-mode=rndwr run
/dev/sda gets about 7 MB/sec
/dev/sdb gets about 3.5 MB/sec
I would expect much higher performance, especially from the SSDs. I have tried many things such as:
1. Enabling write caching using lsiutil
2. echo deadline >/sys/block/sdb/queue/scheduler
3. set options: nodiratime,discard in /etc/fstab
4. enabled TRIM for LVM by setting issue_discards in /etc/lvm/lvm.conf
Does anyone have any other suggestions to improve performance? Thanks.
/dev/sda is a 4 disk IME array of 15k sas seagate ST9146852SS drives
/dev/sdb is a 2 disk IM array of 2 Samsung 840 Pro SSD drives
I'm using sysbench to test: sysbench --num-threads=16 --test=fileio --file-total-size=3G --file-test-mode=rndwr run
/dev/sda gets about 7 MB/sec
/dev/sdb gets about 3.5 MB/sec
I would expect much higher performance, especially from the SSDs. I have tried many things such as:
1. Enabling write caching using lsiutil
2. echo deadline >/sys/block/sdb/queue/scheduler
3. set options: nodiratime,discard in /etc/fstab
4. enabled TRIM for LVM by setting issue_discards in /etc/lvm/lvm.conf
Does anyone have any other suggestions to improve performance? Thanks.