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Default user limits might cause unexpected behavior in Tivoli Storage Manager on Linux

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The default value for the user limit of maximum user processes (nproc) has changed on some distributions and versions of the Linux operating system. The new default value is 1024. This value can cause unexpected behavior in the Tivoli Storage Manager server.


In Red Hat Enterprise Linux (RHEL) 6, the default value for the user limit of maximum user processes (nproc) was decreased to 1024. This value might have changed in other versions and distributions of Linux that are supported by the Tivoli Storage Manager server. Tivoli Storage Manager server users should increase the nproc limit to the minimum recommended value of 16384. If the value is not updated, the server might display unexpected behavior, including hangs or failures.

To verify the current user limit, run the following command as the instance user:

ulimit -u

For example:

[user@Machine ~]$ ulimit -u


To display the current values of all user limits, run the following command:

ulimit -a

For example:

[user@Machine ~]$ 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) 128098
max locked memory       (kbytes, -l) 64
max memory size         (kbytes, -m) unlimited
open files                      (-n) 1024
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) 16384
virtual memory          (kbytes, -v) unlimited
file locks                      (-x) unlimited

To update the user limit of maximum user processes, add a line to the /etc/security/limits.conf file. On RHEL 6, the user limit for nproc is set in the /etc/security/limits.d/90-nproc.conf file. This file overrides the settings in the /etc/security/limits.conf file. To update the user limit, you must either edit the file in the /etc/security/limits.d directory or remove the file and add a line to the /etc/security/limits.conf file.

Document information

More support for: Tivoli Storage Manager

Software version: 6.1, 6.2, 6.3

Operating system(s): Linux

Software edition: All Editions

Reference #: 1599233

Modified date: 05 January 2016

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