HP XP7 Storage - Manual (Page 143)

Setting Up Intermittent Error Monitoring
Intermittent error monitoring is specifiable only when the automatic failback
function is enabled. To prevent an intermittent error from reducing I/O
performance, we recommend that you monitor intermittent errors when
automatic failback is enabled.
When intermittent error monitoring is enabled, you can specify intermittent
error conditions. The default value for the intermittent error-monitoring
interval is 30. The default value for the number of error occurrences is 3.
The system assumes that an intermittent error has occurred if the specified
number of times that the error needs to occur is reached during the specified
monitoring interval (minutes). A path that is assumed to have an intermittent
error is excluded from performing an automatic failback. Intermittent error
monitoring starts right when the path is recovered from the error by
performing an automatic failback. Monitoring is performed on each, individual
path.
When a value of 2 or more is specified for the number of times an error
needs to occur, make sure that the condition shown in Setting Up the
Automatic Failback Function on page 3-74 is satisfied.
To determine whether a path is invalid for an automatic failback, you can use
the results of the dlnkmgr command's view operation.
• Setting up intermittent error monitoring by using the set operation
The following is an example of setting up intermittent error monitoring by
using a command:
dlnkmgr set -iem on -intvl 20 -iemnum 2
on specifies that intermittent error monitoring is to be used. To disable
intermittent error monitoring, specify off. When you set this parameter
to on, you can specify intermittent error conditions by using the -intvl
and -iemnum parameters. Specify the monitoring interval for an
intermittent error in the -intvl parameter, and the number of times that
the error needs to occur in the -iemnum parameter. When these
parameters are omitted, the default values of 30 and 3 are used,
respectively.
Setting Up Dynamic I/O Path Control
To prevent degrading of I/O performance, this function dynamically switches
the output controllers for HDLM, following the switching of controllers
performed by the storage system.
The dynamic I/O path control function can be set for each storage system or
LU. The checking interval for reviewing the switching status information can
also be set in order to properly follow the switching of controllers performed
by the storage system.
The following is an example of setting the dynamic I/O path control function:
Creating an HDLM Environment
3-75
Hitachi Dynamic Link Manager (for Windows®) User Guide