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DarksideEE7

Member

From: Arkansas, United States

Registered: 2009-06-06

Posts: 356

dmraid io scheduler question

Typically I chnage the io scheduler to noop when using a dedicated RAID controller (such as my PERC 5/is) or SSDs with their own integrated microcontroller (OCZ Vertex), but with my OCZ Revodrive I get:

#cat /sys/block/dm-0/queue/scheduler
none

Should this be expected?  I'm getting excellent performance results as per the phoronix iozone bench results:
http://global.phoronix-test-suite.com/? … -141-22575

Really the only performance tweak I've done is the noatime option in fstab....

Thanks

slytux

Member

From: New York

Registered: 2010-09-25

Posts: 129

Re: dmraid io scheduler question

Does dm-0 exist under /sys/block?  What does your /etc/fstab have?  Maybe you can try to apply it to the /dev mountpoints.

Last edited by slytux (2010-12-07 02:47:22)

DarksideEE7

Member

From: Arkansas, United States

Registered: 2009-06-06

Posts: 356

Re: dmraid io scheduler question

Yes, it exists under /sys/block.  Here is fstab:

devpts                 /dev/pts      devpts    defaults            0      0
shm                    /dev/shm      tmpfs     nodev,nosuid        0      0
/dev/mapper/sil_bgbgdjaddicbp1 /boot ext2 defaults 0 1
/dev/mapper/sil_bgbgdjaddicbp2 / ext4 defaults,noatime 0 1
/dev/mapper/sil_bgbgdjaddicbp3 /home ext4 defaults,noatime 0 1
/dev/disk/by-label/Mushkin /home/l33/DLs ext4 defaults,noatime 0 0
none    /tmp     tmpfs     nodev,nosuid,noatime,size=1000M,mode=1777       0       0
shm     /dev/shm tmpfs     nodev,nosuid,size=6G                            0       0

DarksideEE7

Member

From: Arkansas, United States

Registered: 2009-06-06

Posts: 356

Re: dmraid io scheduler question

All of the dmraid partitions show in /sys/block as virtual block devices.  Here they are:

0 lrwxrwxrwx 1 root root 0 Dec  7 03:14 dm-0 -> ../devices/virtual/block/dm-0
0 lrwxrwxrwx 1 root root 0 Dec  7 03:14 dm-1 -> ../devices/virtual/block/dm-1
0 lrwxrwxrwx 1 root root 0 Dec  7 03:14 dm-2 -> ../devices/virtual/block/dm-2
0 lrwxrwxrwx 1 root root 0 Dec  7 03:14 dm-3 -> ../devices/virtual/block/dm-3

Last edited by DarksideEE7 (2010-12-07 09:16:33)