Hi DU Mgrs!
What sort of values do you use to configure the "Parallelism" and
"Sessions per device" parameters of your NSR server? We use 8 and 4
respectively (NSR 3.0a w/ two TZ06 tape drives), and we've been very
happy with the backup performance.
Full restores, on the other hand, are a catastrophe -- I'm averaging way
under 1MB/min in restoring 7GB of data from a blown filedomain, mainly coz
NSR keeps having me switch tapes back and forth seemingly at random during
the restore. Worse, it keeps coming back to tapes I've loaded at an
earlier time, so I have to keep on my toes.
I presume that the combination of parallelism and device concurrency
effectively scattered my backup files across several tapes with no
apparent order (this server is one of 8 in our cluster). This whole
process is driving me crazy (to say nothing of blowing my weekend and
wrecking my sleep pattern -- I could be here for *days*).
Q1: Am I correct in deducing that this abysmal situation is directly
related to parallelism and device concurrency?
Q2a: If so, will setting both values to 1 for future backups get me
savesets striped nicely (ie. in sequential order) across my tapes? (At
this point, I don't give a hoot about the resulting performance hit -- I
just want to ensure that future full restores don't result in tape
gymnastics and multi-day sessions.)
Q2b: If not, what can I do to restore some "order" to this backup
situation, so that I can reduce the need to swap tapes back and forth (and
going back to tapes for the Nth time)?
Thks much for any info. I'll summarize what I get.
- Adrian Ho
adrianho_at_nii.ncb.gov.sg
Received on Sat Apr 20 1996 - 18:14:26 NZST