Veritas Volume Manager 5.1 SP1 Administrator"s Guide (5900-1506, April 2011)

Table 15-2
DMP parameters that are tunable (continued)
DescriptionParameter
The level of detail that is displayed for DMP console
messages. The following level values are defined:
1 — Displays all DMP log messages that existed in
releases before 5.0.
2 — Displays level 1 messages plus messages that
relate to path or disk addition or removal, SCSI errors,
IO errors and DMP node migration.
3 — Displays level 1 and 2 messages plus messages
that relate to path throttling, suspect path, idle path
and insane path logic.
4 — Displays level 1, 2 and 3 messages plus messages
that relate to setting or changing attributes on a path
and tunable related changes.
The default value is 1.
dmp_log_level
Determines if the path probing by restore daemon is
optimized or not. Set it to on to enable optimization
and off to disable. Path probing is optimized only
when restore policy is check_disabled or during
check_disabled phase of check_periodic policy.
The default value is on.
dmp_low_impact_probe
Retry period for handling transient errors. The value
is specified in seconds.
When all paths to a disk fail, there may be certain
paths that have a temporary failure and are likely to
be restored soon. The I/Os may be failed to the
application layer even though the failures are
transient, unless the I/Os are retried. The
dmp_lun_retry_timeout tunable provides a
mechanism to retry such transient errors.
If the tunable is set to a non-zero value, I/Os to a disk
with all failed paths are retried until
dmp_lun_retry_timeout interval or until the I/O
succeeds on one of the path, whichever happens first.
The default value of tunable is 0, which means that
the paths are probed only once.
dmp_lun_retry_timeout
Performance monitoring and tuning
Tuning VxVM
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