VERITAS NetBackupTM 5.0, User Manual And Product Specifications

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The Media Manager Configuration File (vm.conf)
336 NetBackup Media Manager System Administrator’s Guide for Windows
This
vm.conf
entry is used only with the shared storage option (SSO) feature and is read
and interpreted on the host where
ltid
is running.
This entry specifies the name used by the current host to register, reserve, and release
shared drives with
vmd/DA
. The default is the local host name.
SSO Scan Ability Factor
SSO_SCAN_ABILITY = scan_factor
This configuration entry applies only to NetBackup Enterprise Server.
This
vm.conf
entry is used only with the shared storage option (SSO) feature and is read
and interpreted on the host where
ltid
is running.
A scan ability factor can range from zero to 9, with a default value of 5. This factor allows
the assignment of scan hosts to be prioritized, if a drive's scan host changes. Scan hosts
that have a higher scan ability factor are chosen first.
In some SSO configurations, you may have servers that are undesirable for use as the scan
host for a drive. This may be because they have limited resources, are behind firewalls, or
are being administered by people other than NetBackup administrators. These servers can
be configured to never become the scan host for any drive. A scan_factor of zero means
that a server will not become the scan host.
Caution A drive is unavailable for use until a scan host can be assigned for it. If all hosts
that register for a particular drive use scan_factor = 0, the drive will enter an
unusable state until a host with a scan_factor of non-zero registers for the drive.
If all hosts with a scan_factor of non-zero have the drive DOWN, then again the
drive becomes unavailable due to the lack of a scan host.
The decision to use a scan_factor of zero for a server, reduces the level of resiliency in your
SSO configuration. Careful attention to those servers that can be a scan host is required, as
the loss of a scan host for a drive makes it unavailable to any server.
Release Level Considerations
Media Manager servers prior to NetBackup 4.5 FP3 cannot be configured with a
scan_factor of zero. If zero is specified, the default value of 5 is used.
NetBackup release 4.5 (or any 4.5 MP release) device allocation (DA) hosts will accept
registrations from NetBackup 4.5 FP3 media servers (or SAN media servers) with a
scan_factor of zero. A 4.5 release device allocation host handles the zero scan factor the
same as any other legal value. A value of zero is just a scan factor less than one.