[gpfsug-discuss] Interoperability of Transparent cloud tiering with other IBM Spectrum Scale features

[Paul Ward]

I am used to a SCALE solution with space management to a tape tier.
Files can not be migrated unless they are backed up.
Once migrated and are a stub file they are not backed up as a stub, and they are not excluded from backup.
We used the Spectrum Protect BA client, not mmbackup.

We have a new SCALE solution with COS, setup with TCT.
I am expecting it to operate in the same way.
Files can't be migrated unless backed up.
Once migrated they are a stub and a don't get backed up again.
We are using mmbackup.

I migrated files before backup was setup.
When backup was turned on, it pulled the files back.
The migration policy was set to migrate files not accessed for 2 days. All data met this requirement.
Migrations is set to run every 15 minutes, so was pushing them back quite quickly.
The cluster was a mess of files going back and forth from COS.

To stop this I changed the policy to 14 days.
I set mmbackup to exclude migrated files.

Things calmed down.
I have now almost run out of space on my hot tier, but anything I migrate will expire from backup.

The statement below is a bit confusing.
HSM and TCT are completely different.
I thought TCT was for cloud, and HSM for tape?
Both can exist in a cluster but operate on different areas.

This suggest to have mmbackup work with data migrated to a cloud tier, we should be using HSM not TCT?
Can mmbackup with TCT do what HSM does?

https://www.ibm.com/docs/en/spectrum-scale/5.0.5?topic=ics-interoperability-transparent-cloud-tiering-other-spectrum-scale-features
Spectrum Protect (TSM)
For the file systems that are managed by an HSM system, ensure that hot data is backed up to TSM by using the mmbackup command, and as the data gets cooler, migrate them to the cloud storage tier. This ensures that the mmbackup command has already backed up the cooler files that are migrated to the cloud.


Has anyone set something up similar?

Kindest regards,
Paul

Paul Ward
TS Infrastructure Architect
Natural History Museum
T: 02079426450
E: p.ward at nhm.ac.uk<mailto:p.ward at nhm.ac.uk>
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