AIX MULTIPATH DRIVER DOWNLOAD

For disks, this meant that the disk must be closed for example, volume group varied off in order to change attributes. How to Cleanup Multipathing. Configure 4 or 8 paths per disk, or up to 16 paths for rare situations. 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. This gives an indication if the errors are still occurring or if perhaps there was a temporary issue that has not happened recently. Sign in or register to add and subscribe to comments. So, it may continue to attempt to use the path that contains the failing component.

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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.

If using two switches, there is no single point of failure. Paths in those two states must be recovered manually multipsth chpath for Disabled paths or with cfgmgr for Missing paths. Keep in mind that you will need to manually make this change anytime you overwrite the ODM i. Also, note that two different storage device ports have errors indicating that mulitpath issue is not associated with a single port on the storage device.

The following sections discuss the output of various samples of the lsmpio command. There are other possible configurations beyond what is described here that can be considered. MPIO device attributes The following attributes are supported only by multipath devices.

Further problem determination requires knowledge of the SAN fabric topology. More Articles From Chris Gibson. How to find out wheather multipathing is configured in AIX????? ACA is supported starting in Purity 3. This system was connected to an XIV storage system. Connecting to one or more ports on each of the controllers protects against the failure of an entire storage device controller.

If a component has a solid, permanent failure, the failure can be easily detected either by the MPIO software in AIX or by the firmware in the storage device.

For such a device, the PCM uses just the paths to the active or preferred controller as long as there is at least one such path that is enabled and not failed.

Another feature mentioned in the IBM article was the new —U flag for the chdev command. The enhancements in the new TL attempt to distinguish these induced errors from errors caused by the SAN issue to better identify the good paths and the problematic paths.

Storage Multipathing In Solaris In this mode, the PCM only sends path health checks down paths that are marked as failed. This is accomplished by using multiple FC ports on both, the computer and the storage device. Another feature of the recent improvements to the AIX MPIO software is the expansion of the output of the lsmpio command to include error counts per adapter and per remote port, allowing the SAN administrator to better deduce the source of intermittent, recurring errors.

Also notice that the errors occurred across all of the remote ports accessed by fscsi1. A device-specific PCM can have device and path attributes.

IBM Systems Magazine - New lsmpio Command Provides Better View of MPIO | AIX | IBM Systems Magazine

Communications adapter removal Before you can remove or replace a hot-plug adapter, you must unconfigure that aux. This makes AIX less dependent on the health check commands to detect path failures or to recover paths when using Fibre Channel.

If scheduled maintenance is planned for a SAN or for a storage device, it is best to identify the disk paths that will be impacted by that maintenance and use the rmpath command to manually disable those paths before starting the maintenance. SAN administrators may use several configuration techniques to maximize redundancy.

The new improvements, include the following items:. This simulates the failing components in different parts of the SAN. A device that has multiple controllers can designate one controller as the active or preferred controller.

This will require a reboot on the initiator, and the steps are as follows: And from the AIX chdev man page: Note that the lsmpio command depends on support from the PCM.

Multiple Path I/O

When the lsmpio command is used, you might see output as shown in Example 3. What you set it to will need to be unique, you can set this value to "0x1" for example. 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.