Veritas Storage Foundation 5.1 SP1 Advanced Features Administrator"s Guide (5900-1503, April 2011)

The -C option is useful to process active files before any other files. For best

results, specify the -T option in conjunction with the -C option. Specifying both

the -T option and -C option causes the fsppadm command to evacuate any cold

files first to create room in the SSD tier to accommodate any active files that will

be moved into the SSD tier via the -C option. Specifying -C in conjunction with

-T confines the scope of the scan, which consumes less time and resources, and

thus allows frequent scans to meet the dynamic needs of data placement.

See “Enforcing a placement policy” on page 345.

See the fsppadm(1M) manual page.

With the help of the map, instead of scanning the full file system, you can confine

the scan to only the files on the SSD tiers in addition to the active files that VxFS

recorded in the FCL. This scheme potentially achieves the dual purpose of reducing

the temperature time granularity and at the same time reducing the scan load.

Example placement policy when using solid state disks

The following snippet is one possible placement policy for use with solid state

disk (SSD)-based tiers.

<?xml version="1.0"?>

<!DOCTYPE PLACEMENT_POLICY SYSTEM "/opt/VRTSvxfs/etc/placement_policy.dtd">

<PLACEMENT_POLICY Version="5.0" Name="SSD_policy">

The first two RELOCATEs will do the evacuation

out of SSDs to create room for any relocations

into the SSDs by the third RELOCATE. The parameters

that can be tuned are basically values for PERIOD and

the values of MIN and/or MAX as the per the case.

The values for MIN and MAX are treated as multiples of

average activity over past 24 hour period.

</COMMENT>

</SELECT>

create files on ssdtier, failing which

create them on other tiers

</COMMENT>

<ON>

Administering SmartTier

Using SmartTier with solid state disks

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