[Lustre-discuss] Performance parameters

Brian J. Murrell
Fri, 06 Jun 2008 16:09:13 -0000

On Fri, 2008-06-06 at 17:47 +0200, Enrico Morelli wrote:
> On Fri, 06 Jun 2008 11:24:28 -0400
> "Brian J. Murrell" <Brian.Murrell at Sun.COM> wrote:
>
> > So, about 48MiB/s, yes?  What does your storage backend look like?
>
> The server is connected to an MSA60 with 7x500GB SATA HDD in RAID 6.

Have you measured the throughput of the device(s) you are using as
OST(s) on the OSS(es)?

You also reported that your network is capable of 30MB/s.  That already
doesn''t seem right since you are getting 48MiB/s of throughput.

> Sorry, sorry, sorry, I''m very tired. I connected directly to the
NFS
> server :-(((( On a client machine the time is more than 1 minutes.

So Lustre is 3x faster than NFS?

Are you happy with your 48MiB/s from your Lustre filesystem?

> The problem is that a lot of people

Which people?

> told me that ''ls'' required a lot of
> time, a ''cp'' required a lot of time, all operations on
lustre
> filesystem are very slow.

So you want faster than 48MiB/s?  You need to have the hardware capable
of delivering that.  If you want better than 48MiB/s (and certainly you
can get way, way higher with the right hardware) you first need to
determine what your hardware is capable of.  You need to benchmark your
OSTs and then benchmark your network.  Only when you know what the
components are capable of can you determine what the aggregation of them
should be able to deliver.

> The people that works on lustre has a lot of
> files to manage, so testing his directories I found that an
''ls'' require
> a lot of time and the same for ''cp'' and
''rm'' operations.
>
> The dd was not a better test to do. Sorry again.

Yeah.  For throughput, use a real benchmark like IOR, iozone, etc.
While that will be a good example of what cp will do, it is not a good
example to compare ''ls'' to as ''ls'' is a
metadata heavy application, not
file i/o heavy.

b.

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