[Linux-cluster] GFS slower than NFS ???

[Rainer Duffner]

R Wahyudi wrote:
>
> Hi Wendy,
>
> Thanks for your comment.
> If this is the case then .. GFS or clustered storage is not the
> "ideal" solutions for storage server that use Maildir ?


I do think so.

> - Most of the time POP/IMAP jobs is to stat directory
> - And users can have large number of email in a directory


What versions of RHEL/GFS are you using?

GFS is supposed to have a smaller overhead, compared to NFS.
However, I'm not sure this pays out in case a maildir-mailstorage is
clustered.
I've mentioned this before: in case of qmail as MTA, qmail itself goes
to great lengths to avoid any filename- and locking-collisions in the
maildir - it doesn't need any kind of lock-manager (GULM/DLM).
I suppose, it turns out to be counter-productive.
I don't consider "NFS" to be ideal - anectodical evidence suggests that
NFS is also very sub-optimal. It may just turn out, that it's the
lesser-evil.

I would be really interested in seeing head-to-head hard data evidence
comparing a NFS-setup (with Solaris or FreeBSD) and a GFS-setup with
several runs of postal (http://www.coker.com.au/postal/), just for kicks.
Unfortunately, I don't have the time (nor exactly the resources to do it
myself).




cheers,
Rainer