Hmmm, as hardware and files vary, the only way to
really know is to try it.

We run all our backups with maxtapebuf set, so I am not sure
what impact it has. Might be in the 10% range, noticable but
not hugely important.

I run MOST of our backups with INTER set, and on the bigger backups
it makes it run faster (say from about 4.5mb a second to 5.5mb/sec.)
However, if you then restore from these tapes, the files you want
may be scattered all around.

Running 3 backups may use enoug cpu and disc that your tapes
don't run at full speed. When a backup is going, do all tapes
flash continuously, or do some stop for periods of time?

With 3 backups going, you are already hitting multiple disc files
and disc and controllers at once, something the INTER would do
on a single backup, so you may not benefit much from it.

You also may be approaching the speed limit of the SCSI controller
for your DDS drives. Are they all on the same controller?

Are you using hardware compression? This can dramatically speed up
backups, so consider enabling it if you haven't already.

-----Original Message-----
From: Scott Root [mailto:[log in to unmask]]
Sent: Wednesday, May 30, 2001 8:05 AM
To: [log in to unmask]
Subject: [HP3000-L] Store Options


Hi all,

I'm trying to improve our backup time and am looking for a few opinions.

Can someone tell me of any potential pitfalls or problems when using the
MAXTAPEBUF & INTER (together or separately) options during a STORE command?

If they are used together, will backup time improve or will one limit the
other?

We're running MPE 6.0 PP1 and use TurboStore to DDS2 tape drives.  We have
three backup jobs running simultaneously, all of them finishing within 30
minutes of each other.  All of them store files from all disks, and roughly
the same amount of data.  This was originally done to try and get them to
finish at approximately the same time.  Our current STORE commands look
something like this:

:STORE @[log in to unmask],@[log in to unmask]  &
:;*DLYTAPE;COMPRESS=HIGH;DIRECTORY;SHOW=LONG;PROGRESS=5


The backups in question would only be restored to the same system or one
configured alike.

All input appreciated,
Scott Root

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