a very simple problem, but unknown solution
Benson, Paul
PBenson at ibasis.net
Thu Dec 13 10:59:03 GMT 2001
In our environemt, we use PCs (NT) running a JVM that produces unique file
names, and data content about 100K or less. We only write to these file. The
JVM (the application) does spawn many threads so the net effect can be many
simultaneous file creation requests from one PC.
All the files are written to a samba mounted directory, and the directory
*file* itself does get somewhat large. The directory name is MM-DD-YY so it
changes every 24 hours.
Here's the problem .... as the directory gets larger and at about 400K, the
file creation slows down, and it slows down, it appears because samba is
looping calling getdents() hundreds of times without doing anything else as
if it needs to read every entry in the directory for every file 'open'
requested.
AND each PC seems to be bound to exactly one Samba server. The Samba
'listener' never forks more then one server per PC, and I guess that is
expected.
So the bottle neck seems to be this single client connection, and all those
getdent() calls.
The server is Solaris 7, 4 cpu, and we're not out of mem, but for 4 PCs each
at most generating 8 files simultaneously, when the target directory reaches
400K, the servers are using 100% cpu.
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