[gpfsug-discuss] mmbackup questions

[Jonathan Buzzard]

I have been looking to give mmbackup another go (a very long history
with it being a pile of steaming dinosaur droppings last time I tried,
but that was seven years ago).

Anyway having done a backup last night I am curious about something
that does not appear to be explained in the documentation.

Basically the output has a line like the following

        Total number of objects inspected:      474630

What is this number? Is it the number of files that have changed since
the last backup or something else as it is not the number of files on
the file system by any stretch of the imagination. One would hope that
it inspected everything on the file system...

Also it appears that the shadow database is held on the GPFS file
system that is being backed up. Is there any way to change the location
of that? I am only using one node for backup (because I am cheap and
don't like paying for more PVU's than I need to) and would like to hold
it on the node doing the backup where I can put it on SSD. Which does
to things firstly hopefully goes a lot faster, and secondly reduces the
impact on the file system of the backup.

Anyway a significant speed up (assuming it worked) was achieved but I
note even the ancient Xeon E3113 (dual core 3GHz) was never taxed (load
average never went above one) and we didn't touch the swap despite only
have 24GB of RAM. Though the 10GbE networking did get busy during the
transfer of data to the TSM server bit of the backup but during the
"assembly stage" it was all a bit quiet, and the DSS-G server nodes
where not busy either. What options are there for tuning things because
I feel it should be able to go a lot faster.


JAB.

-- 
Jonathan A. Buzzard                         Tel: +44141-5483420
HPC System Administrator, ARCHIE-WeSt.
University of Strathclyde, John Anderson Building, Glasgow. G4 0NG