[CentOS] home directory server performance issues

Mon Dec 10 18:50:11 UTC 2012
m.roth at 5-cent.us <m.roth at 5-cent.us>

Matt Garman wrote:
> I’m looking for advice and considerations on how to optimally setup
> and deploy an NFS-based home directory server.  In particular: (1) how
> to determine hardware requirements, and (2) how to best setup and
> configure the server.  We actually have a system in place, but the
> performance is pretty bad---the users often experience a fair amount
> of lag (1--5 seconds) when doing anything on their home directories,
> including an “ls” or writing a small text file.
> So now I’m trying to back-up and determine, is it simply a
> configuration issue, or is the hardware inadequate?
Without poring over your info, let me give you something that bit us here:
our home directory servers are all 5.x (in this case, 5.8). Here's the
reason: when we tried 6.x, if you were in an NFS-mounted directory,
working from the same, or another NFS-mounted directory, it was *slow*.
Unzipping a file that was about 120M or so took 6.5-7 *minutes*, as
opposed to 1 min. After extensive testing (the numbers are still on our
whiteboard here, from when I did it many months ago), it didn't seem to
matter what the workstation was running, but it did matter what the NFS
server was. You *can* solve it by changing from sync to async... if you're
not worried about possible data loss or corruption. We do have to worry,
since in some cases, our researchers might be dumping many gigs of data
into their home directories from a job that's been running for days, and
no one wants to rerun that.