[OpenAFS] volume size

Rich Sudlow rich@nd.edu
Fri, 14 Jan 2011 12:18:19 -0500

Lewis, Dave wrote:
> Hi,
> I'm wondering what is a reasonable size for large AFS volumes. I
> understand that the maximum size of a volume is about 2 TB (assuming
> that the partition is at least that size). From a practical standpoint,
> is it reasonable to have a 2 TB volume? Should I expect any problems
> doing operations like bos salvage or vos move on large volumes?

We've been using 2 TB volumes for several years - even with that we often need
to create multiple volumes per user - it's just plain impractical for
us to use anything smaller and would like to see the 2 TB volume limit
raised (I believe it is in 1.6..??) - We have had some unique problems
that I don't believe others have seen but between Derrick and Sine Nomine
all of our problems are fixed in 1.4.14.  Yes it takes a while to move
volumes - our run of thumb is 200 GB/hr for moves. It also takes a
while to create 100's of volumes for a single user ;-)  Except for one
volume (fixed in 1.4.14) we haven't had issues for over a year.
> For example, I'm wondering if bos salvage has a "harder" time with a few
> large volumes than with several smaller volumes. I figure that, with
> smaller volumes, internal inconsistencies that bos salvage fixes would
> be more isolated than with large volumes, and that that would be
> beneficial. But I don't really know.
> Currently we mount 25 GB volumes in users' home directories for their
> image data, which grows a lot during data processing. Some users are
> starting to feel limited by 25 GB volumes, so I'm considering going to
> 100 GB volumes. I would appreciate any advice. Should large volumes be
> salvaged more often than small volumes?

No difference - We generally don't salvage except for hardware problems except
for the volume mentioned earlier - which is on it's separate server.
  Not sure how big your images are but OpenAFS actually
does a better job with small files vs our Panasas server - 100 GB is our
default home directory size.

> We're running openafs 1.4.11 on centos 5.3.

If you're using large volumes run 1.4.14 there are some salvage , fileserver
fixes there.


Rich Sudlow
University of Notre Dame
Center for Research Computing
310 West South St
South Bend, In 46601

University of Notre Dame
Center for Research Computing
PO Box 539
Notre Dame, IN 46556-0539

(574) 807-1046 (cell)

> Thanks,
> Dave
> ============================================================== 
> David P. Lewis 
> Center for Advanced Brain Imaging, Division of Medical Physics 
> The Nathan S. Kline Institute for Psychiatric Research 
> 140 Old Orangeburg Road, Orangeburg, NY 10962 
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