[Fwd: RE: [ofa-general] NFS-RDMA (OFED1.4) with standard distributions ?]

[Tom Tucker]

Jeff:

Unfortunately, the NFSRDMA transport cannot make your disks go faster. 
If the storage subsystem is incapable of keeping up with IPoIB, then it 
won't be able to keep up with NFSRDMA either.

To compare NFSRDMA and IPoIB performance absent a very fast storage 
subsystem you'll need to keep the file sizes small enough such that they 
fit within the server cache.

Tom


Jeff Becker wrote:
> Hi. Just passing this on in case you missed it. Do you have any advice
> on what knobs to tweak to get better performance (than NFS/IPoIB)? Thanks.
> 
> -jeff
> 
> -------- Original Message --------
> Subject: 	RE: [ofa-general] NFS-RDMA (OFED1.4) with standard
> distributions ?
> Date: 	Mon, 10 Nov 2008 16:27:50 +0000
> From: 	Ciesielski, Frederic (EMEA HPC&OSLO CC) <frederic.ciesielski at hp.com>
> To: 	Jeff Becker <Jeffrey.C.Becker at nasa.gov>
> CC: 	general at lists.openfabrics.org <general at lists.openfabrics.org>
> References:
> <7391130E01ED404FBD7A3C86731EEB7D20EC0F8737 at GVW1087EXB.americas.hpqcorp.net>
> <49160618.3050409 at nasa.gov>
> 
> 
> 
> That's great, thanks.
> 
> I ran some tests with the 2.6.27 kernel as server and client, and basically it works fine.
> 
> I could not find yet any situation where NFS-RDMA would outperform NFS/IPoIB, at least when you compare apples to apples (same clients, same server, same protocol, and not just write to/read from the caches), and it even seems to have severe performance issues for reading with files larger than the memory size of the client and the server.
> Hopefully this will improve when more users will be able to give valuable feedback...
> 
> Fred.
> 
> -----Original Message-----
> From: Jeff Becker [mailto:Jeffrey.C.Becker at nasa.gov]
> Sent: Saturday, 08 November, 2008 22:35
> To: Ciesielski, Frederic (EMEA HPC&OSLO CC)
> Cc: general at lists.openfabrics.org
> Subject: Re: [ofa-general] NFS-RDMA (OFED1.4) with standard distributions ?
> 
> Ciesielski, Frederic (EMEA HPC&OSLO CC) wrote:
>> Is there any chance that the new NFS-RDMA features coming with OFED
>> 1.4 work with standard and current distributions, like RHEL5, SLES10 ?
> Not yet, but I'm working on it. I intend for NFSRDMA to work on 2.6.27 and 2.6.26 for OFED 1.4. The RHEL5 and SLES10 backports will likely be done for OFED 1.4.1. Thanks.
> 
> -jeff
> 
>> Did anybody test this, or would pretend it is supposed to work ?
>>
>> I mean without building a 2.6.27 or equivalent kernel on top of it,
>> keeping almost full support from the vendors.
>>
>> Enhanced kernel modules may not be sufficient to work around the
>> limitations of old kernels...
>>
>>
>>
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