[OpenAFS] Maximum volume size (again)

Christopher D. Clausen cclausen@acm.org
Wed, 17 May 2006 11:22:45 -0500

Steve Simmons <scs@umich.edu> wrote:
> On May 16, 2006, at 2:15 PM, Jeffrey Hutzelman wrote:
>> On Tuesday, May 16, 2006 02:06:22 PM -0400 Derrick J Brashear
>> <shadow@dementia.org> wrote:
>>> On Tue, 16 May 2006, John W. Sopko Jr. wrote:
>>>> .... Is the recommendation still
>>>> 8GB for OpenAFS 1.4.1? Are there any notes on maximum volume
>>>> and file sizes? Thanks for the info.
>>> You'll be sad if you ever need to move it unless you have fast
>>> stuff all
>>> around.
>> You'll be sad because big volumes take a long time to move.
>> You'll be more sad if the volume consists of a very large number of
>> small files, rather than a few large files.  If it's going to be
>> lots of little files, you should encourage the user to structure
>> his data so that multiple volumes can be used.
> Has anyone done any comparisons to determine if the time to move a
> single
> large volume is significantly different than the time to move the
> equivalent files in smaller volumes? I'm doing some testing, and may
> give this a shot.
> (And, before anybody jumps in to point out the advantages of being
> able to deal with things that come in smaller chunks: yes, I know
> that. I just want to know if you more more than an additive penalty
> for the large volume vs the volume set.)

I've noticed that the larger volumes are locked for more time during 
clone and delete operations.  This may or may not be a problem in your 
environment though.  I find it rather annoying to be denied access to 
files for more than 30 seconds and some of our larger volumes take 
minutes to clone.