Friday, September 7, 2012

OSB, number of files open

We run an environment with Whole Server Migration.

An important point is to make sure that we have enough resources (file handles) on a machine to be able to run 2 Managed Server - in case we migrate one.

This is how you discover how many files are used by the user "soa":

/usr/sbin/lsof -u soa | wc -l

It turned out that a single server running the Admin and 4 Managed Servers required some 9000 files. An important load was represented by the MANY Datasources we need to deploy.

This command:
ulimit -a

will tell you the hard limit imposed by the Linux Kernel:

ulimit -a
core file size (blocks, -c) 0
data seg size (kbytes, -d) unlimited
scheduling priority (-e) 0
file size (blocks, -f) unlimited
pending signals (-i) 132607
max locked memory (kbytes, -l) 32
max memory size (kbytes, -m) unlimited
open files (-n) 8192
pipe size (512 bytes, -p) 8
POSIX message queues (bytes, -q) 819200
real-time priority (-r) 0
stack size (kbytes, -s) 10240
cpu time (seconds, -t) unlimited
max user processes (-u) 132607
virtual memory (kbytes, -v) unlimited
file locks (-x) unlimited

apparently the limit is flexible, even with a limit of 8192 we were able to open 9050 files...

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