[dm-devel] RE: dm-devel Digest, Vol 16, Issue 20

[goggin, edward]

On Mon, 20 Jun 2005 20:46:34 +0200
christophe varoqui <christophe.varoqui at free.fr> wrote

> Speaking of optimization, have you witnessed too the ~20% performance
> decrease with multi-path PG ?

Sorry, but I haven't been paying enough attention to this performance
degradation thread.

I just tried a simple sequential block file system and raw (4kb)
writing and read/writing for single dd(1) thread of 2GB LU with multibus
path grouping policy (EMC Symmetrix) with 2 paths and a 100 minio count
value and noticed very little drop (5% elapsed time as reported by time(1))
in throughput verses doing the same with the native scsi device path.
Five percent is certainly livable.  I did not compare with the failover
path group policy though.