Processes Attached to the root Lnode

For reasons of system management, processes attached to the root lnode are given almost all the CPU resources they demand. Therefore, if a CPU-bound process is attached to the root lnode, it will tie up a CPU, causing processes on other lnodes to slow or stop.

The following precautions can be taken to prevent this from occurring:

• The administrator should always log in to an lnode created for normal use by the administrator, rather than attaching to the root lnode. If there is a need to attach to the root lnode, be careful not to use any CPU-intensive applications, such as compilers. To use a UID of superuser without attaching to the root lnode, the administrator can use the su(1) command.

• The init.d scripts can be changed to use the srmuser program to attach all daemons to lnodes of their own, so they are not attached (by inheritance) to the root lnode. However, this solution cannot be routinely recommended. It can be a burden since a large number of files need to be edited, and the practice could inhibit the ability to integrate patches into a system later. A resolution that does not require this task to be performed manually is under investigation.

  For Solaris Resource Manager releases after 1.0, the scripts sbin_rc2 and sbin_rc3 provided in the /usr/srm/unsupport directory can be used to partially solve this problem.

A program that runs as setuid-root does not automatically attach to the root lnode. Normally, the process remains attached to the lnode of the parent that created it, and only the effective UID is changed.