What is activeDiagnosticPartition?

[adityan20]

For a host under config property I see activeDiagnosticPartition new property for ESX4 servers. What does this refer to?

In ESX3.5, we always considered the Logical units under property path config.storageDevice.multipathInfo as Host disk. But now in the ESX4 should we consider this activeDiagnosticPartition as the host disk. ( as this relates to virtual center value)

In ESX4, there is a new property called config.multipathState. what does this refer to?

Thanks in advance.

[lamw]

activeDiagosticPartition has actually been there since ESX 3.5 (VI SDK 2.5) and it looks like it might have been there as of 2.0 as well, it's not a new feature.

http://www.vmware.com/support/developer/vc-sdk/visdk25pubs/ReferenceGuide/vim.host.DiagnosticPartiti...

I think you might have some questions regarding the new multipathing configurations which has been introduced in vSphere, which utilizes a new Pluggable Storage Architecture which allows the native multipathing by VMware but also the ability to allow 3rd party vendors to provide their own multipathing for their storage.

You can find more information about this new architecture here: http://www.yellow-bricks.com/2009/03/19/pluggable-storage-architecture-exploring-the-next-version-of...

This should help get you in the right direction and give you an idea of what some of these params are doing.

=========================================================================

William Lam

VMware vExpert 2009

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[admin]

DiagnosticPartition is a Core dump partition for storing VmKernel core dumps made on PSOD and "activeDiagnosticPartition" is the diagnostic partition that will be set as the current diagnostic partition on the host. "activeDiagnosticPartition" is not suitable to be used as the host disk. It is not a new feature and was there since ESX 3.0.1.

Regarding your other query on HostMultipathStateInfo and HostMultipathInfo object, these are not interchangable. As per definition these have different utility.

HostMultipathStateInfo is a data object that describes the state of storage paths on the host. All storage paths on the host are enumerated in this data object.

The reason all path state information is encapsulated in this data object is because the path may actively change. This data object ensures that a request to gather path state changes only needs to fetch this data object.

HostMultipathInfo is data object that describes the multipathing policy configuration to determine the storage failover policies for a SCSI logical unit. The multipathing policy configuration operates on SCSI logical units and the paths to the logical units.

Note: In hosts where HostMultipathStateInfo is not defined or does not exist on the HostStorageDeviceInfo object, only native multipathing exists. That means for these hosts, the MultipathInfo object contains the complete set of LUNs and paths on the LUNs available on the host.

[adityan20]

Thanks alot for the detailed response.