MVThsm: Off-Host HSM Recycle

MVThsm: Off-Host HSM Recycle

Use HSM without the Tradeoffs

HSM users have a long history of balancing mainframe and storage resources against workload demands. For all its value as a backup and storage management powerhouse, HSM consumes expensive MSUs for data movement and Control Dataset (CDS) updates in order to reclaim tape capacity as datasets expire.

MVThsm shifts capacity optimization, normally achieved by the HSM recycle process, to the MVT tape infrastructure itself without mainframe CPU cycles for tape reads/writes or HSM CDS updates.

an efficient approach that continuously improves

MVThsm uses a lightweight started task to collect a list of expired datasets at customizable intervals. After that, the process of reclaiming HSM tape capacity happens entirely on the MVT, with all tape reads and writes being performed without FICON I/O.

Tapes with expired datasets are transparently rewritten, replacing expired 16 kilobyte blocks with 16 byte blocks, keeping the same VOLSER and block IDs and reducing the size of expired datasets by 99.9%. As a result, the cloned tapes retain all of the location information for the remaining valid datasets, allowing the HSM CDS to continue using its existing references and skipping the need for the CPU-intensive process of updating the CDS.

MVThsm optimizes tape capacity without mainframe MSUs

MVThsm creates space efficient clones of HSM tapes by pruning expired datasets without mainframe MSUs or the need to update HSM Control Datasets.

Each time an HSM tape is optimized by MVThsm, the tapes get smaller in size which, in turn, reduces the time for the cloning process and for replicating the tape to DR and thus continuously improving performance.

By off-hosting capacity optimization, the process can be run more frequently, enabling existing MVT users to postpone tape storage upgrades and allowing new MVT users to fit existing workloads into smaller configurations.