Properly manage Archive Mode flag in TS1150/TS1155 tape drives

The IBM TS1150 and TS1155 Enterprise tape drives has a configuration setting called Archive Mode [1] which controls whether archive mode unthread (also called low tension refresh) should be performed on tape unload. In recent firmwares [2] the default has changed from disabled to enabled, which causes tape unloads to always take 284 seconds instead of 36 seconds. This is a severe performance degradation in an environment with many tape load/unload operations.

From what we have understood doing the low tension refresh is only required when tapes are to be stored for a long time in a hot and humid, ie non-climate controlled, environment. For installations employing tape libraries, which are installed in proper climate controlled environments, doing low tension refresh should only be necessary when tapes are checked out from the tape library.

We propose the IBM 3592 tape drive support in Spectrum Protect to be enhanced to manage the Archive Mode flag in the tape drive, enabling installations in climate controlled environments to disable Archive Mode for normal operations.

Ideally the Archive Mode flag could be set on the Device Class level, allowing for different classes of data to be treated differently.

A further enhancement would be to enable Spectrum Protect to perform low tension refresh when tapes are removed from a tape library, presumably to be transported/stored in what might be suboptimal conditions. This could for example be done leveraging the existing CheckLabel functionality in the CHECKOUT LIBVOLUME command. If a tape is mounted with the Archive Mode flag enabled when checking the volume label then low tension refresh would be performed on volume unmount.

[1]
http://www-01.ibm.com/support/docview.wss?uid=ssg1S7003248
[2]
https://www.ibm.com/support/knowledgecenter/en/STQRQ9/com.ibm.storage.ts4500.doc/performance_specs_3592_drives.html