[gpfsug-discuss] SOBAR questions

[Simon Thompson (Research Computing - IT Services)]

We've recently been looking at deploying SOBAR to support DR of some of
our file-systems, I have some questions (as ever!) that I can't see are
clearly documented, so was wondering if anyone has any insight on this.

1. If we elect not to premigrate certain files, are we still able to use
SOBAR? We are happy to take a hit that those files will never be available
again, but some are multi TB files which change daily and we can't stream
to tape effectively.

2. When doing a restore, does the block size of the new SOBAR'd to
file-system have to match? For example the old FS was 1MB blocks, the new
FS we create with 2MB blocks. Will this work (this strikes me as one way
we might be able to migrate an FS to a new block size?)?

3. If the file-system was originally created with an older GPFS code but
has since been upgraded, does restore work, and does it matter what client
code? E.g. We have a file-system that was originally 3.5.x, its been
upgraded over time to 4.2.2.0. Will this work if the client code was say
4.2.2.5 (with an appropriate FS version). E.g. Mmlsfs lists, "13.01
(3.5.0.0) Original file system version" and "16.00 (4.2.2.0) Current file
system version". Say there was 4.2.2.5 which created version 16.01
file-system as the new FS, what would happen?

This sort of detail is missing from:
https://www.ibm.com/support/knowledgecenter/STXKQY_4.2.2/com.ibm.spectrum.s
cale.v4r22.doc/bl1adv_sobarrestore.htm

But is probably quite important for us to know!

Thanks

Simon