Limit Node Overview

Solaris Resource Manager is built around a fundamental addition to the Solaris kernel called the lnode (limit node). Lnodes correspond to UNIX user IDs (UIDs) and can represent individual users, groups of users, applications, and special requirements. Lnodes are indexed by UID; they are used to record resource allocation policies and accrued resource usage data by processes at the user, group, and application levels.

Although an lnode is identified by UID, it is separate from the credentials that affect permissions. The credential structure determines whether a process can read, write, and modify a file. The lnode structure is used to track the resource limits and usage.

In certain cases, a user might want to use a different set of limits. This is accomplished by using srmuser(1SRM) to attach to a different lnode. Note that this change does not affect the credential structure, which is still associated with the original UID, and that the process still retains the same permissions.