[OpenAFS] Performance issue with "many" volumes in a single /vicep?

Steven Jenkins steven.jenkins@gmail.com
Wed, 17 Mar 2010 17:48:33 -0400

On Wed, Mar 17, 2010 at 12:50 PM, Steve Simmons <scs@umich.edu> wrote:
> We've been seeing issues for a while that seem to relate to the number of=
 volumes in a single vice partition. The numbers and data are inexact becau=
se there are so many damned possible parameters that affect performance, bu=
t it appears that somewhere between 10,000 and 14,000 volumes performance f=
alls off significantly. That 40% difference in volume count results in 2x t=
o 3x falloffs for performance in issues that affect the /vicep as a whole -=
 backupsys, nightly dumps, vos listvol, etc.
> My initial inclination is to say it's a linux issue with directory search=
es, but before pursuing this much further I'd be interested in hearing from=
 anyone who's running 14,000 or move volumes in a single vicep. No, I'm not=
 counting .backup volumes in there, so 14,000 volumes means 28,000 entries =
in the directory.

Could you provide filesystem information? (e.g., what filesystem, what
parameters given/used by mkfs, etc)  That information is often quite

In particular, since you mention Linux, I'm guessing you're using
ext3.  With journaling (ie, ext3 and not ext2)?  With directory
hashing turned on?

Steven Jenkins