[Lustre-discuss] [Lustre-Performance] Lustre performance on SLES 11 x86-64

[Andreas Dilger]

On 2009-10-30, at 05:49, udara weerapperuma wrote:
> I have SLES 11 x86-64  and lustre v 1.8.1.1 installed in it. This  
> use as MDS and OSS.
>
> /dev/sda3 ----2 GB------ MDT
> /dev/sdb2 ----5 GB------ OST1
> /dev/sdb3 ----5 GB------ OST2
> /dev/sdb5 ----5 GB------ OST3
> /dev/sdb6 ----5 GB------ OST4
>
> Then I have 2 clients running on SLES 11 x86-64 and SLES 10 SP2  
> x86-64 both has the lustre v 1.8.1.1 installed.
> The SLES 10 client gives the same speed for every bs value in dd  
> command (dd if=/dev/zero of=/lustre/sles10.out bs=1k gives 43 MB/s)
> This is same for the every bs value on SLES 10 SP2.
>
> But for the SLES 11 x86-64 client gives only 4 MB/s speed for the  
> small bs values. (bs=1k) It gives 45 MB/s for the bs=32k values and  
> up.


Using multiple partitions on the same disk is a sure way to get very bad
performance.  Secondly, bs=1k is also a good way to add a lot of  
overhead
to the IO.  At a minimum use bs=4k (to match the client page size).

Cheers, Andreas
--
Andreas Dilger
Sr. Staff Engineer, Lustre Group
Sun Microsystems of Canada, Inc.