[linux-lvm] LVM2 stripe performance

[Dave Olien <dmo@osdl.org>]

I'm running tiobench on an LVM2 striped logical volume.  I'm  comparing
the LVM2 striping performance with a similar striping configuration
using a hardware RAID controller.

With hardware RAID, I'm able to get about 66 megabytes per second on
sequential writes, and 52 megabytes per second with random writes.

With LVM2, I can get only 23 megabytes per second with either random
or sequential writes.

Read performance on LVM is about 10% less than with hardware RAID.
e.g. with 48 threads, hardware RAID sequental reads are 105 megabytes
per second, LVM2 RAID sequential reads are 95 megabytes per second.

This is using an ext2 file system, mounted with noatime.

I think I recall seeing email with similar problems to this on this
mail list.  If I recall, the cause had to do with ordering of requests
submitted to disk.

Has there been any work to address this?

Thanks!

Dave Olien