Larry will be able to add more, but I thought I would throw in my 2 ¢.
volDB is for Media Manager and it is recommended it be on a single server,
usually the master (it exists on all media servers, but should only be used on
the one. the others aren't used and I have actually heard of many people
deleting them and stopping the service so they're not accidentally used). It
contains:
- what tapes exist
- where (volume pool/volume group)
- expiration of the tape within media manager (e.g. when the tape is no longer
considered good)
- # mounts
- status - assigned or unassigned (if assigned, to who? NetBackup or Storage
Migrator)
mediaDB is for NetBackup and exists on every media server. It contains:
- expiration of the tape within NetBackup (e.g. when the images expire)
- retention level
- status - full, active, available, mpx, frozen, suspended
You can do an alternate server restore from a media server that is not the
original (although I believe it is slower), so it won't stop you from doing a
restore, but here are reasons I can think of to make sure you backup the
mediaDB.
1.) I believe the process to unassign media is done by contacting each media
server. If you decommissioned a media server without following the proper
steps (bpmedia -movedb), or were not able to restore a failed media servers
mediaDB, the volume could become "orphaned" and could potentially cause the
media to stay assigned when there are no valid images left.
2.) Many of the reports and commands (ex. bpexpdate) require contact with the
media server to be ran. If the media servers mediaDB doesn't contain
information on the volumes, the reports will be inaccurate and the commands
may fail.
3.) The mediaDB is contacted when a volume is needed for backup. If it
doesn't have any active volumes to use, it then goes to the volDB to request a
new volume be assigned to it. A restored media server without it's mediaDB
wouldn't use any of it's previously used tapes and would request new ones.
4.) Because VERITAS says so. I wouldn't risk being in an unsupported
configuration when I needed help from support just because I didn't back up
these tiny db's on each media server.
My guess on the media server with 0 KB mediaDB is that it is a media server
but is only being backed up as a client or once was used as a media server but
all tapes containing images have since expired and became unassigned.
- Scott
"Sixbury, Dan"
<sixbury AT celeritas DOT com> To:
"'larry.kingery AT veritas DOT com'" <larry.kingery AT veritas DOT com>
Sent by: cc: "EBU (E-mail)"
<Veritas-bu AT mailman.eng.auburn DOT edu>
veritas-bu-admin AT mailman DOT eng. Subject:
[Veritas-bu] NetBackup Database backups
auburn.edu
10/22/2001 09:00 AM
Larry,
What is enhanced authorization data? Also the mediaDB, what does this
contain? I know that there is a volDB and a mediaDB. What is the
difference between these two. Also, I checked one of our media servers and
it contained a size of 0 for the mediaDB. Isn't this stored on the master
server? Is there some additional information that would help provide
compelling reasons for media servers being included in the NetBackup
database backups. I know the documentation states that all media servers
should have their database and db directories backed up, but I am trying to
prove "why" to some disbelievers by showing what the media server contains
that is not on the master server. ;-)
Thanks
Dan
-----Original Message-----
From: Larry Kingery [mailto:larry.kingery AT veritas DOT com]
Sent: Tuesday, October 16, 2001 2:59 PM
To: Sixbury, Dan
Cc: veritas-bu AT mailman.eng.auburn DOT edu
Subject: RE: [Veritas-bu] Immediately Backup DB while backups are
running?
A session is the time from when no backups are running and one or more
backups start, to the time that no backups are running. So if you
have a class scheduled to start at 4:00 and another at 5:00, you can
not say whether this is one or two sessions just based on this
information.
If the db backup is active, backup jobs will queue. I'm not sure what
happens if you launch a db backup (say via cron) during other backups.
If you don't backup a media server, you risk losing the license keys,
enhanced authorization data, device configuration, mediaDB, etc.
The storage unit (in NetBackup terminology) is configured on the
master. The physical device configuration lives on the media server.
But, just because you only configure certain things on the media
server doesn't mean that NetBackup doesn't store other things there
which need to be protected.
HTH,
L
Sixbury, Dan writes:
> If you have NetBackup Database backups scheduled to run after each session
> of scheduled backups,
> 1. Is NetBackup smart enough to queue the NB DB backup between other
backups
> that are scheduled?
> 2. If the NetBackup DB backup tries to run while another backup is
running,
> does the NB DB backup wait in queue or does it fail, or does it run and if
> it runs does this mean that it is an invalid backup?
>
> I have typically scheduled the NetBackup database backups from cron and
used
> the command line options to backup the database at a time that I know
other
> backups are not running. I just want to know what happens when other
> backups are running or get queued to run how NetBackup handles those
> situations. Especially how NetBackup handles the "after each session of
> scheduled backups". The other thought here is that if we have
multiplexing
> and multiple schedules, we could have 4 different backups running and each
> ending at a different time with no period of inactivity between start and
> finish of the four backups.
>
> So far as Media servers. If you keep all of the volume database
information
> on the master server, what does the media server provide that needs to be
> backed up? I thought that the only thing that should be configured on the
> Media servers should be the storage unit, and then have all classes,
backup
> policies, media pools, etc. configured on the master. What am I missing
if
> one of the media servers doesn't get a NetBackup db backup?
>
> Thanks,
> Dan
>
--
Larry Kingery
Don't use a big word where a diminutive one will suffice.
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