SL3000 - Drive is De-allocated From its Owning Partition When the Drive is Deleted From the Media Validation Pool

Asset ID:	1-71-2017321.1
Update Date:	2017-12-11
Keywords:

Solution Type Technical Instruction Sure

Solution 2017321.1 : SL3000 - Drive is De-allocated From its Owning Partition When the Drive is Deleted From the Media Validation Pool

Applies to:

Sun StorageTek SL3000 Modular Library System - Version All Versions to All Versions [Release All Releases]
Information in this document applies to any platform.

Goal

Take a drive out of a FC/SCSI partition into the Media Validation Pool then Delete that drive to return it back to it's owning partition after the Media Validation task is completed.

Solution

A drive that was added in Media Validation Pool in a partitioned SL3000 happened to be de-allocated from the partition it belonged to after the drive was removed/deleted from the Media Validation Pool.
This caused an out-of-sync condition in the SCSI Element ID numbering between the library and the Commvault software application.

According to the description made by the customer the SCSI Element Addressing went out-of-sync after the drive was removed/deleted from the MV Pool.

Nothing was reported by the customer to fall apart at the application level after the drive was added to the MV Pool. This is matching with the enhancement added in library code in reference to Bug 16674725 [https://bug.oraclecorp.com/pls/bug/webbug_edit.edit_info_top?rptno=16674725] The Enhancement does eliminate the need to renumber the drives, keeping contiguous Drive Element IDs for a given partition when a drive is assigned to the Media Validation Pool.

The enhancement brings the following Media Validation behavior:
1) SCSI Mode Sense will still report all drives for a non-partitioned SCSI library, even if 1 or more drives are in the Media Validation pool.
2) SCSI Mode Sense will still report all drives within a partition, even if 1 or more drives are in the Media Validation pool.
3) SCSI Read Element Status will report Element Disabled (ED=1) in the Element Data for the drive in the Media Validation pool.
4) A SCSI move to/from a drive in the Media Validation pool, will result in a Check Condition with new sense data: 05/3Bh/18h -- "Illegal Request, Drive Disabled".

This enhancement was added in code version FRS_4.30 which is the initial release of SL3K code version that added support for the Media Validation.

The issue resides with the drive removed from the MV Pool is being assigned the last Element ID as explained in the User's Guide:

"When removing drives from the MV pool, the library and partitions remain online.
The library logically assigns the drive the last element ID regardless of the drive’s
physical location. When the library comes back online, SCSI hosts receive two Unit
Attentions: "Not Ready to Ready Transition" and "Mode Parameters Changed". You
should initiate a re-configuration. For a partitioned library, you must allocate the drive
slot removed from the MV pool to a partition (see "Partitioning the Library" on
page 5-1 of the SL3000 User's Guide)".

References

<BUG:16674725> - ADDING A DRIVE TO THE MEDIA VALIDATION DRIVE POOL -- BREAKS THE SCSI INTERFACE

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