Re: Performance expectations of NFS

[Bernd Schubert <bernd-schubert@gmx.de>]

Hi Christian,

>   0:05  - Server: locally on RAID-5
>   0:06  - Client: copying from NFS mount to tmpfs
>   2:31  - Client: Copying from NFS mount to NFS mount
>           (i.e., the simple command above)
>   3:30  - Client: Copying from NFS mount to NFS mount over an existing
>           tree.
>   5:08  - Client: Copying from tmpfs to NFS mount
>   0:48  - Client: Deleting copy of tree on NFS mount

I guess your exports has the "sync" option or your didn't set  async or syn=
c =

at all (sync is then the default)? Can you repeat the test again using the =

async option? But please, also read carefully the explanations of "man 5 =

exports" about this topic. =


>
> Now I know that file creation is synchronous, and that because of this,
> the NFS copy will /always/ run significantly slower. But I was amazed at
> just how much faster reading was than writing, and at how fast reading
> actually is -- it's much faster than I expected NFS could be.

Just for fun, take ethereal and capture some data, once with the async and =

once with the sync option. Now have a look how much time each operation of =

the nfs client takes before it gets confirmed by the server. Especially loo=
k =

at the commit calls, once with sync and once with async option.

> But what I'd really like to know if there is a way of making the
> above operation run in significantly less time than it is today, or if

I guess if one could convince the nfs clients to reduce the number of commi=
t =

calls, write operations would be much much faster. Don't know if that is =

possible at all, though.


Cheers,
Bernd


-- =

Bernd Schubert
PCI / Theoretische Chemie
Universit=E4t Heidelberg
INF 229
69120 Heidelberg


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