Everyone,
Thanks for the feedback you've provided to my query below. I'm glad I'm
not the only one who thought of this, and a lot of you raised very good
points I haven't thought about. While I've been following parallel
filesystems for years, I have very little experience actually managing
them up to this point. (My BG/P came with GPFS filesystem for /scratch,
but everything was already setup before I got here, so I've only had to
deal with it when something breaks).
You've all convinced me that this may not be an ideal solution
arrangement, but if I go this route, GPFS might be a better fit for this
than Lustre (mainly because Chris Samuels has proven it *is* possible
with GPFS, and GPFS has snapshotting).
Joe Landman, as always, has provided a wealth of information, and the
rest of you have pointed out other potential pitfalls. with this approach.
Thanks again for the feedback, and please keep the conversation going.
Prentice
On 12/23/2014 12:12 PM, Prentice Bisbal wrote:
Beowulfers,
I have limited experience managing parallel filesytems like GPFS or
Lustre. I was discussing putting /home and /usr/local for my cluster
on a GPFS or Lustre filesystem, in addition to using it just for
/scratch. I've never done this before, but it doesn't seem like all
that bad an idea. My logic for this is the following:
1. Users often try to run programs from in /home, which leads to
errors, no matter how many times I tell them not to do that. This
would make the system more user-friendly. I could use quotas/policies
to encourage them to use 'steer' them to use other filesystems if needed.
2. Having one storage system to manage is much better than 3.
3. Profit?
Anyway, another person in the conversation felt that this would be
bad, because if someone was running a job that would hammer the
fileystem, it would make the filesystem unresponsive, and keep other
people from logging in and doing work. I'm not buying this concern for
the following reasons:
If a job can hammer your parallel filesystem so that the login nodes
become unresponsive, you've got bigger problems, because that means
other jobs can't run on the cluster, and the job hitting the
filesystem hard has probably slowed down to a crawl, too.
I know there are some concerns with the stability of parallel
filesystems, so if someone wants to comment on the dangers of that,
too, I'm all ears. I think that the relative instability of parallel
filesystems compared to NFS would be the biggest concern, not
performance.
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