2002-08-27 07:09:06

by Reimar Bauer

[permalink] [raw]
Subject: speed for NFS

Dear all,

in the next few years we will have much amount of
data something about 70 - 100 TByte.

At the moment with our configuration nfs speed is
quite less against the network speed.
I believe this could be extended and this is necessary.

The max transfer rate we have is about 3MByte/sec.

Is there a possibility to increase this to 30MByte/sec.
Is this relalistic?
Where can I get a description about this?


For the scenario clients are mostly linux, aix or cray.
The server is momentanly an aix system.


regards

Reimar Bauer





--
Reimar Bauer

Institut fuer Stratosphaerische Chemie (ICG-I)
Forschungszentrum Juelich
email: [email protected]
-------------------------------------------------------------------
a IDL library at ForschungsZentrum Juelich
http://www.fz-juelich.de/icg/icg-i/idl_icglib/idl_lib_intro.html
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2002-08-27 09:30:16

by Ragnar Kjørstad

[permalink] [raw]
Subject: Re: speed for NFS

On Tue, Aug 27, 2002 at 09:08:56AM +0200, Reimar Bauer wrote:
> Dear all,
>=20
> in the next few years we will have much amount of
> data something about 70 - 100 TByte.
>=20
> At the moment with our configuration nfs speed is=20
> quite less against the network speed.
> I believe this could be extended and this is necessary.
>=20
> The max transfer rate we have is about 3MByte/sec.
>=20
> Is there a possibility to increase this to 30MByte/sec.
> Is this relalistic?=20
> Where can I get a description about this?=20

Yes, 30MB/s is realistic for nfs (sequantial access) - on our RAIDs
we are able to do approxemately 50-60 MB/s over NFS (gigabit ethernet).

You first need to make sure your local access is fast enough. For
nfs-access to reach 30MB/s local access must be significantly higher, as
there is some overhead in NFS. (Our RAIDs do approxemately 100-120 MB/s
locally). Increasing readahead setting might help for reads.

For configuring NFS I would start with making sure you're using NFS v3.
Next, enable jumbo-frames (if you do large transfers over gigabit
ethernet) and increase buffer-sizes.



--=20
Ragnar Kj=F8rstad
Big Storage


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2002-08-27 14:12:35

by Lever, Charles

[permalink] [raw]
Subject: RE: speed for NFS

hi reimar-

> in the next few years we will have much amount of
> data something about 70 - 100 TByte.
>
> At the moment with our configuration nfs speed is
> quite less against the network speed.
> I believe this could be extended and this is necessary.
>
> The max transfer rate we have is about 3MByte/sec.
>
> Is there a possibility to increase this to 30MByte/sec.
> Is this relalistic?
> Where can I get a description about this?

3MB/s is poor even for 100base-T. as ragnar suggested,
you should test and possibly improve the local disk speed
on your servers. you may have fast disks on your servers,
but they may not be scaling well if there are many clients
accessing them concurrently. possibly, reorganizing your
data sets across existing spindles can improve scalability.

i also recommend that you study your current network set up.
if there are packet losses, this will adversely impact the
performance of your NFS clients. look carefully at your
switches to be sure they are not dropping packets. look
at "netstat -s" and "nfsstat -c" on your clients to be
certain they see a healthy network.

there is a Linux NFS FAQ at http://nfs.sourceforge.net that
has many useful ideas about how to assess and improve your
performance picture.


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