Veritas™ File System 5.0.1 Administrator's Guide

The following example illustrates a possible companion rule that relocates files

from tier2 volumes to tier1 ones based on their I/O temperatures. This rule

might be used to return files that had been relocated to tier2 volumes due to

inactivity to tier1 volumes when application activity against them increases.

Using I/O temperature rather than access age as the relocation criterion reduces

the chance of relocating files that are not actually being used frequently by

applications. This rule does not cause files to be relocated unless there is sustained

activity against them over the most recent two-day period.

<FROM>

</SOURCE>

</FROM>

<TO>

</DESTINATION>

</TO>

<WHEN>

</IOTEMP>

</WHEN>

</RELOCATE>

This rule relocates files that reside on tier2 volumes to tier1 volumes if their

I/O temperatures are above 5 for the two day period immediately preceding the

issuing of the fsppadm enforce command. VxFS relocates qualifying files in the

order in which it encounters them during its file system directory tree scan. When

tier1 volumes are fully occupied, VxFS stops scheduling qualifying files for

relocation.

VxFS file placement policies are able to control file placement across any number

of placement classes. The following example illustrates a rule for relocating files

with low I/O temperatures from tier1 volumes to tier2 volumes, and to tier3

volumes when tier2 volumes are fully occupied:

<FROM>

165Dynamic Storage Tiering

File placement policy rules