It also introduced some new features to the AIX operating system that I thought were worth exploring and discussing further. When disabling multiple paths for multiple LUNs, rmpath is simpler than chpath , as it does not have to be run on a per-disk basis. A PCM can support one or more specific devices. I encourage you to read the documentation for this command on the AIX Information Center to learn more. View Public Profile for h foorsa. Changes the characteristics of the device while allowing the device to remain in the Available state.

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Please repeat this for all devices. Following that is a table showing the error count for the remote port that was in use when the error occurred.

There are several possible combinations of using VIOS with Pure Storage, and the configurations differ depending on which one you are using. Both fscsi0 and fscsi1 are able to use some remote ports without errors or with very few errors while attempts to access one particular storage device port result in many errors.

Disk Flash Servers Software Tape. This flag instructs chdev to attempt a dynamic update of the attribute value. As a result, the default values for the attributes are appropriate for most situations. The new improvements, include the following items:. Note that there could be cases where the error total listed directly under the adapter exceed the sum of the errors on the remote ports under the adapter, as some errors may not be associated with a particular remote port.


IBM AIX multipath I/O (MPIO) resiliency and problem determination

Optimal performance in a failed path scenario is to ensure that the ordered path list alternate paths between separate fabrics. This flag cannot be used with the -P or multipwth flag. For most attributes and most levels of AIX, attributes could historically only be changed on devices that were not in use.

However, the timeout policy attribute cannot account for all possible error scenarios. For disks, this meant that the disk must be closed for example, volume group varied off in order to change attributes.

The health checker never aox paths that are in a Disabled or Missing state. For example, you can quickly determine if any errors have been recorded for a device. More information can be found here: The set of user changeable attributes is defined by the device vendor. Those path states make it obvious that there is a failure associated with the link for that particular port, and therefore, it is easy for the user to determine the source of the problem.

Remove the current ODM file. The path health check mode determines the paths that the MPIO’s path health checker will probe for path availability during wix business operations. This can lead to much quicker recovery from a command time out and also much quicker detection of situations where all paths to a device have failed.

Note that the lsmpio command depends on support from the PCM.

Versions prior to AIX 6. Reboot, as prompted by the tool. After the maintenance is complete, the paths can be re-enabled with cfgmgr. The FC jammer was connected to the fiber from the storage device port to the FC switch. Likewise, using multiple FC ports on the storage device protects against the failure of a single port. Recent technology levels of AIX also make use of asynchronous events from the Fibre Channel FC multipatn drivers aid manipulate path states.


Many storage devices are designed with two or more controllers. This will require a reboot on the initiator, and the steps are as follows: If no disk that is accessed through that port is open, then the count stays at zero.

IBM AIX multipath I/O (MPIO) resiliency and problem determination

Sign in or register to add and subscribe to comments. All these types of errors may allow some FC packets to be transmitted correctly on the path, while other packets on that same path experience errors, causing a connection to partially work. The path priority values miltipath ignored by this algorithm.

With this flag, the attribute value can be changed without closing the disk and the change takes effect immediately. The disk attributes described in the following sections can be displayed by using the lsattr command, and can be changed with the chdev command.