Setting the mvfs_expected_zone_count environment variable

The mvfs_expected_zone_count environment variable allows you to specify the number of zones in which you plan to run the MVFS.

The recommended value for this variable is the expected total number of zones (both global and non-global) that are running Rational® ClearCase® on that computer. Rational ClearCase uses this variable to compute the scaling factor and cache sizes for the MVFS. Specifically, the total available memory on the system is divided by the number of expected zones, and then the standard algorithms are applied to set the scaling factor and cache sizes.

If mvfs_expected_zone_count is not set, the scaling factor in the global zone is computed based on the total system memory size, and the scaling factor in non-global zones is set to one by default. Without specifying the number of zones on the system, it is difficult to allocate the proper cache sizes for the MVFS equitably across zones. This can have performance implications.

To set the value of mvfs_expected_zone_count:

  1. Log on to the global zone as root.
  2. Edit the /etc/system file. Insert this line:

    set mvfs:mvfs_expected_zone_count = number_of_zones

    where number_of_zones is the expected number of global and non-global zones where the MVFS will be running on this computer.

  3. Reboot the computer.
Parent topic: MVFS caches in Solaris zones
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