Verifying access rights and user limits

Before you start the Tivoli® Storage Manager server on an AIX®, HP-UX, Linux, or Solaris operating system, verify access rights and user limits.

1. Verify that the server instance user ID has permissions to start the server.
2. For the server instance that you plan to start, ensure that you have authority to read and write files in the server instance directory. Verify that the dsmserv.opt file exists in the server instance directory, and that the file includes parameters for the server instance.
3. If the server is attached to a tape drive, medium changer, or removable media device, and you plan to start the server by using the instance user ID, grant read/write access to the instance user ID for these devices. To set permissions, take one of the following actions:
   • If the system is dedicated to Tivoli Storage Manager and only the Tivoli Storage Manager administrator has access, make the device special file world-writable:

     chmod +w /dev/rmtX

   • If the system has multiple users, you can restrict access by making the Tivoli Storage Manager instance user ID the owner of the special device files:

     chmod u+w /dev/rmtX

   • If multiple user instances are running on the same system, change the group name, for example TAPEUSERS, and add each Tivoli Storage Manager instance user ID to that group. Then, change the ownership of the device special files to belong to the group TAPEUSERS, and make them group writable:

     chmod g+w /dev/rmtX

4. If you are using the Tivoli Storage Manager device driver and the autoconf utility, use the -a option to grant read/write access to the instance user ID.
5. To prevent server failures during interaction with DB2®, tune the kernel parameters.
6. Verify the following user limits by using the guidelines in the table.

   Table 1. User limit (ulimit) values

   User limit type	Preferred value	Command to query value
   Maximum size of core files created	Unlimited	ulimit -Hc
   Maximum size of a data segment for a process	Unlimited	ulimit -Hd
   Maximum file size	Unlimited	ulimit -Hf
   Maximum number of open files	65536	ulimit -Hn
   Maximum amount of processor time in seconds	Unlimited	ulimit -Ht

   To modify user limits, follow the instructions in the documentation for your operating system.

   Tip: If you plan to start the server automatically by using a script, you can set the user limits in the script.
7. Verify the system-wide value for the maximum number of open files. The system-wide value must be equal to or greater than the user limit for the maximum number of open files.
8. Ensure that the minimum suggested value of 16384 is specified for the user limit of maximum user processes (the nproc setting).
   1. To verify the user limit, issue the ulimit -Hu command. For example:

      [user@Machine ~]$ ulimit -Hu
      16384

   2. If the limit of maximum user processes is not set to 16384, set the value to 16384:
      Add the following line to the /etc/security/limits file:

      instance_user_id         -    nproc           16384

      where instance_user_id specifies the server instance user ID.
      Add the following line to the /etc/security/limits.conf file:

      instance_user_id        -    nproc           16384

      where instance_user_id specifies the server instance user ID.
      If the server is installed on the Red Hat Enterprise Linux 6 operating system, set the user limit by editing the /etc/security/limits.d/90-nproc.conf file in the /etc/security/limits.d directory. This file overrides the settings in the /etc/security/limits.conf file.

      Tip: The default value for the user limit of maximum user processes changed on some distributions and versions of the Linux operating system. The default value is 1024. If you do not change the value to the minimum suggested value of 16384, the server might fail or hang.