Managing Host I/O Timeouts For An Online Upgrade; Hp-Ux; Default Timeout Values - HP 6100 Software Manual

Counter
Mirror Data Rate
Prefetch Data Rate

Managing host I/O timeouts for an online upgrade

The default values for host operating parameters such as LUN timeout and queue depth are typically
set to values that ensure proper operation with the storage system. These values are appropriate for
most storage system operations, including online controller software upgrades. In general, host LUN
timeouts of 60 seconds or more are adequate to accommodate an online upgrade. In most situations
it will not be necessary to alter these settings to perform an online controller software upgrade.
If any host timeout values have been decreased to less than 60 seconds, it will be necessary to reset
them to their original default value. The following section provide a summary of the steps and commands
involved in checking and changing timeout values for each supported operating system. See the
operating system documentation for more information.
NOTE:
Unless otherwise noted, cluster testing with online controller software upgrades has not been completed.
Cluster information will be added to this document when the testing is complete.

HP-UX

CAUTION:
Because HP-UX supports boot across Fibre Channel SAN, any change to default SCSI timeouts on
the HP-UX host may cause corruption and make the system unrecoverable.

Default timeout values

• Sdisk timeout: 30 seconds
• (LVM) lvol timeout: 0 seconds
HP StorageWorks 4x00/6x00/8x00 Enterprise Virtual Array Updating Product Software Guide (XCS
Description
The rate at which data travels across the mirror port to complete read and write
requests to a virtual disk. This data is not related to the physical disk mirroring
for Vraid1 redundancy. Write data is always copied through the mirror port
when cache mirroring is enabled for redundancy. In active/active controllers,
this counter includes read data from the owning controller that must be returned
to the requesting host through the proxy controller. Reported mirror traffic is al-
ways outbound from the referenced controller to the other controller.
The rate at which data is read from the physical disk to cache in anticipation
of subsequent reads when a sequential stream is detected. Note that a sequential
data stream may be created by host I/O and other I/O activity that occurs be-
cause of a DR initial copy or DR full copy.
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