HP 6400/8400 HP StorageWorks Enterprise Virtual Array Updating Product Softwar - Page 31

Managing host I/O timeouts for an online upgrade, HP-UX, Default timeout values

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Counter Mirror Data Rate Prefetch Data Rate 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 always 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 because of a DR initial copy or DR full copy. 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. IMPORTANT: Depending on your operating system, changing timeout values may require a reboot of your system. To minimize disruption of normal operations, schedule reboots one node at a time. In a cluster environment, plan your reboots one node at a time and shut down the passive node to avoid unwanted automatic failover. 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 (default=0, retries forever) HP StorageWorks Enterprise Virtual Array Updating Product Software Guide (XCS 09534000) 31

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Description
Counter
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.
Mirror Data Rate
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.
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.
IMPORTANT:
Depending on your operating system, changing timeout values may require a reboot of your system.
To minimize disruption of normal operations, schedule reboots one node at a time. In a cluster
environment, plan your reboots one node at a time and shut down the passive node to avoid unwanted
automatic failover.
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 (default=0, retries forever)
HP StorageWorks Enterprise Virtual Array Updating Product Software Guide (XCS 09534000)
31