PowerPath: What does asb:iopf stand for in powermt display dev=all?

Summary: This article explains what asb:iopf stands for in powermt display dev=all?

This article applies to This article does not apply to This article is not tied to any specific product. Not all product versions are identified in this article.
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Symptoms

The powermt display dev=all command shows hardware path with asb:iopf instead of alive:

Symmetrix ID=xxxxxxxxxxx
state=alive; policy=SymmOpt; queued-IOs=0
=============================================================================================
--------------- Host ---------------------------------------- -Stor- -I/O Path- -Stats-
### HW Path I/O Paths Interf. Mode State Q-IOs Errors
=============================================================================================
3072 pci@1e,600000/SUNW,qlc@3,1/fp@0,0 c3t50000972081ADD18d4s0 FA 7eA asb:iopf alive 0 0
3074 pci@1e,600000/SUNW,qlc@3/fp@0,0 c2t50000972081ADD1Cd4s0 FA 8eA active alive 0 0

Cause

Not applicable

Resolution

The setting asb:iopf stands for -Auto standby intermittent I/O failure algorithm.
This feature, the intermittent I/O failure algorithm, means the path will not be used unless all other active paths are dead.
asb path mode settings do not persist across reboots.

This can be turned on using the following options:

Turn on: Powermt set autostanby=on trigger=iopf

Turn off: Powermt set autostanby=off trigger=iopf

Usages: powermt set autostandby={on|off|reinitialize} [trigger={prox|iopf}]

trigger=iopf selects only the IOsPerFailure-based autostandby feature. This determines whether or not a path that has intermittent I/O failures should be placed into autostandby mode (asb:iopf).


You can override autostandby for a path by running powermt set mode={standby|active} dev=<path> force.
If the path is already in the requested mode, then the command is ignored.

dev=<path>|<device>|all sets the mode for the specified path, or all paths to the specified device. all specifies all paths to all devices. The default is all.

Example for device path:
Powermt set mode=active dev=/pci@8,700000/QLGC,qla@3/sd@

Example for all devices:
Powermt set mode=active dev=all devices

Powermt set mode=active dev=all devices

To verify if the asb:iopf is disabled or enabled check powermt display options or powermt display dev=all.

Additional Information

This feature is also available in PowerPath for HP-UX beginning with PowerPath 5.2 and PowerPath 5.5 for Solaris.

Refer to the  EMC ® PowerPath ® Family Version 5.5 and 5.2 for HP-UX CLI and System Messages Reference P/N 300-010-600 REV A05.


The following modes are available in powermt set mode:
  • active - specifies a path that will be actively used for I/O for multipathing.
  • standby - specifies a path that has been manually placed in standby mode by the user. This path will not be used unless all other active paths are dead. This path state cannot change unless the user changes it back to active.
  • asb-  (for autostandby) specifies a path that has been placed into standby automatically either using the VPLEX proximity autostandby algorithm (asb:prox) or the intermittent I/O failure algorithm (asb:iopf). This path will not be used unless all other active paths are dead. asb path mode settings do not persist across reboots.
  • unlic -indicates that unlicensed PowerPath is running for a Symmetrix, VNX, and CLARiiON storage system (no license key has been installed). In this scenario, all paths are marked unlicensed except one path to each SP. Unlicensed paths cannot become candidates for path failover.

Affected Products

PowerPath
Article Properties
Article Number: 000047102
Article Type: Solution
Last Modified: 24 Apr 2021
Version:  3
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