On Wed, Nov 22, 2006 at 11:02:54AM +0000, Dieter wrote: > In message <[EMAIL PROTECTED]>, Kris Kennaway writes: > > > > > I'm surprised that you're seeing that much of a "hang". Even if the di= > > sks > > > > are busy, the system should slow down all disk processes equally, so no > > > > one process "blocks", but they're all a little slower. > > >=20 > > > I collected a bit of data: > > >=20 > > > While copying a large file from disk1 to disk2, > > >=20 > > > time ls on a small directory on disk3 (not cached in memory) > > >=20 > > > real 0m0.032s > > > user 0m0.000s > > > sys 0m0.003s > > >=20 > > > time ls on a small directory on disk2 > > >=20 > > > real 4m51.911s > > > user 0m0.000s > > > sys 0m0.002s > > >=20 > > > I expect access to a busy disk to take longer, but 5 minutes is > > > a bit much. And that's the root directory of the filesystem, > > > it didn't have to follow a long chain of directories to get there. > > >=20 > > > Sometimes I see long delays when accessing disk3, but it is > > > behaving at the moment. > > > > ls still has to acquire a number of locks in order to be sure that the > > contents of the directory aren't changing. If there are lots of other > > processes all competing for these locks, it will be slow. It looks > > like that's the case on your system, although details of your workload > > have been trimmed from your email. > > In telnet window 1: > > cd /disk1/ > cp -ip very_big_file /disk2/bar/ (the workload) > > In telnet window 2: > > time ls /disk3/foo1/ (make sure time and ls are cached in memory) > time ls /disk3/foo2/ (see timing numbers above) > time ls /disk2/ (see timing numbers above) > > The /disk2/ directory is small, only contains 3 directories and .snap > > Would the cp into /disk2/bar/ lock the /disk2/ directory?
It shouldn't do. What scheduler are you using? Kris
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