Releaser Process

When file system utilization exceeds its configured high-water mark (HWM), the file system management software invokes the releaser, which does the following:

• Reads the releaser.cmd file and collects the directives that control the release process

• Scans the file system and collects information about each file

• Begins releasing files in priority order

A file system can contain thousands of files. Keeping track of the release priority for every file can be wasteful, because releasing only several large files might return the file system to its low-water mark (LWM). However, the releaser must examine the priority of each file or risk missing the best candidates for release. The releaser does this by identifying the first 10,000 candidates. It then discards subsequent candidates if they do not have a priority greater than the lowest-priority candidate among the first 10,000.

After the releaser has determined the priority of the first 10,000 candidates, it selects the files with the highest priority for release. After releasing each file, the releaser checks whether the file system cache utilization is below the low-water mark. If so, it stops releasing files. If not, it continues releasing the files in priority order.

If the releaser has released all 10,000 candidates and the file system is still above the low-water mark, it starts over and identifies 10,000 new candidates.

The releaser exits if it cannot find any viable candidates. This situation can occur, for example, if files do not yet have archive copies. In this case, the SAM software starts the releaser again after one minute has elapsed.

The high-water and low-water marks are set with the high= percent and low= percent file system mount options. For more information about these mount options, see mount_samfs(1M) in Sun QFS and Sun Storage Archive Manager Reference Manual.