[Veritas-bu] How will NetBackup behave

2001-12-07 10:45:27
Subject: [Veritas-bu] How will NetBackup behave
From: david AT xbpadm-commands DOT com (David A. Chapa)
Date: Fri, 7 Dec 2001 09:45:27 -0600
the 1am backups will wait for an available drive.  The implication is that
the 8pm backup jobs that are ACTIVE will have to finish, since it is
multiplexed, it is only finished when the last MPX job submitted is
finished.  The class priority is not a preemptive feature, therefore ACTIVE
jobs do not look to see there is a higher priority class waiting for a tape
drive.  I believe bpsched will examine the queued jobs and see the 1am jobs
have a higher priority and thus will submit them now before any 8pm jobs
continue to run, but again this scenario is a bit skewed because of MPX,
non-MPX would probably be a better scenario for this explanation.

I'm trying to remember if I have tested this before or not...I know I have
used class priority before.

It all depends on whether bpsched examines the queued jobs or if once they
are queued, their order is set.

So, Veritas am I close?

David A. Chapa
NetBackup Consultant
DataStaff, Inc.
847 413 1144
NBU-LSERV AT datastaff DOT com - Adv. Scripting

-----Original Message-----
From: veritas-bu-admin AT mailman.eng.auburn DOT edu
[mailto:veritas-bu-admin AT mailman.eng.auburn DOT edu]On Behalf Of Jason
Sent: Friday, December 07, 2001 8:51 AM
To: Veritas BU
Subject: [Veritas-bu] How will NetBackup behave

In this scenario, does anyone know how NetBackup will behave.

At 8pm, a large number of backup jobs are queued. Multiplexing is enabled
for these backups. Priority of these backups is 0. Retention level is 4
At 1am, more backups start. Possible the original set from 8pm are not
finished yet. Priority of these backups is 5. Retention is 1 year.

I know NetBackup will not mix backups with different retentions on the same
tape. However NetBackup will give those 1am backups a higher priority and
perform them when it determines is it's first opportunity (given that they
have a higher priority)

My quesiton is, when will NetBackup determin is it's 'first opportunity'.
Does it have to wait until the original Priority 0 backups are done? During
a  tape change? Because the original set of Priority 0 backups are
multiplexed, there should not be a point in time when images are not being
sent to them until the set is done, but this kindof breaks off the idea of
setting a priority to happen at 'first available' opportunity...



Jason Ahrens, Systems Analyst
TELUS Enterprise Solutions
The Future is Friendly

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