RE: question about rman

[Mandar A. Ghosalkar]

Title: question about rman

even in netbackup and ebu configuration, the hot backup starts only when the hot backup job is kicked by the netbackup schedular and not while in queue.

The only problem is when the hot backup is started, mutiple netbackup jobs are created and queued for each tablespace. for ex, i hv 2 drives and i do parallel=2 in ebu, so two jobs are created simultaneously for 2 diff tablespaces. when one tablespace job (one dynamically created netbackup job) is finished, the next tablespace is put in hot and a seperate job is created and fired. now i hv say 15 tablespaces, and during this whole process my other operating system os files job is kicked in, it would create multiple jobs dynamically for each mount point.

 

so

 

tablespace1 hot started

tablespace2 hot started

tablespace1 hot complete

tablespace3 hot started

/u01 job queued

tablespace2 hot complete

/u01 job started this runs for 5 hrs

tablespace3 hot complete

..

..

 

so by the time hot backup finishes its early morning.

 

solution: schedule job with proper timings and prioritise them.

 

my 2 cents (sorry no change), my 1 penny :)

 

 -----Original Message-----
From: Chris Stephens [mailto:[EMAIL PROTECTED]]
Sent: Tuesday, January 21, 2003 1:17 PM
To: Multiple recipients of list ORACLE-L
Subject: RE: question about rman

even if that is true (which is news to me and might cause some consideration for our oltp databases...maybe)  we won't be able to predict when the database will go down in the case of a cold backup.  ...which we can't live with here.  ...loads are scheduled for certain times throughout the night.  even in the oltp environment, this might cause a performance degradation if the backups start after our call centers are open for business.

 

thanks for the info though.  i'll do some checking for omniback. 

-----Original Message-----
From: Sujatha Madan [mailto:[EMAIL PROTECTED]]
Sent: Tuesday, January 21, 2003 2:37 PM
To: Multiple recipients of list ORACLE-L
Subject: RE: question about rman

Correct me if I am wrong, but I thought the backup software will only initiate the RMAN backup once your server has reached the top of the queue and it is ready to be written to tape. At least that's what happens with Legato.

 

Regards,

Sujatha

 

-----Original Message-----
From: Chris Stephens [mailto:[EMAIL PROTECTED]]
Sent: Wednesday, 22 January 2003 7:05 AM
To: Multiple recipients of list ORACLE-L
Subject: RE: question about rman

The problem is that if we try and backup to tape, we have to wait in the queue.  Depending on what is already there, we may have to wait a number of hours before RMAN has the opportunity write data to the tape.  Believe me, we have tried to devise ways to predict when we could actually write to tape but the sys admin has stated over and over that he has no control over when a tape is available due to the queueing.  In a cold backup this implies unacceptable downtime.  In a hot backup it means that the database will be backed up over a very long period of time.

 

So if we first backup to disk and then let omniback take the data to tape whenever it gets around to it, we'll still be able to due a recovery through RMAN if the necessary files are on tape (a place that RMAN is unaware of).

 

note: obviously we are going to have to test this but i'd like to know that it is possible before i go through the trouble of coordinating something with the sys admins.

 

thank you.

 

 

-----Original Message-----
From: Freeman Robert - IL [mailto:[EMAIL PROTECTED]]
Sent: Tuesday, January 21, 2003 1:31 PM
To: Multiple recipients of list ORACLE-L
Subject: RE: question about rman

I guess my first question is why not just backup to tape through the Omniback MML layer? Or, if you prefer to go to disk you can backup to disk with RMAN and then backup the backupset to tape through the MML with RMAN again. If you try to restore from an RMAN backup, and the required backup pieces are not there, RMAN will let you know.

 

HTH,

 

Robert

 

Robert G. Freeman
Technical Management Consultant
TUSC - The Oracle Experts www.tusc.com
904.708.5076 Cell (it's everywhere that I am!)
Author of several books you can find on Amazon.com!

-----Original Message-----
From: Chris Stephens [mailto:[EMAIL PROTECTED]]
Sent: Tuesday, January 21, 2003 10:45 AM
To: Multiple recipients of list ORACLE-L
Subject: question about rman

I could test this myself but that would require coordination with the system administrators and they always seem to think their time is too important for testing. :)

i would like to implement RMAN in and 8.1.7.2 oltp environment and 9.2.0 warehouse environment.  We use Omniback as an enterprise wide backup solution.  Don't know if this is version specific so I thought I would mention.  Here's the question....

Currently we are doing os level backups for both environments.  We take the backup to disk and then omniback backs up the mountpoints we write to.  A problem we have is that we are unable to predict when omniback will get to our backup mountpoints

due to the fact that there is a queue that serializes our backups and other servers are place in that queue ahead of us.  This is a factor in our warehouse environment as it makes the downtime of a cold backup unpredictable.  In the oltp environment this makes the length of backups unpredictable and GREATLY increases redo generation.  The only option we have is to first backup to disk.

So here's my problem with RMAN...if we backup to disk through rman and then omniback takes that data to tape and the backup mountpoints are overwritten the very next time a backup is taken then RMAN's ability to find the necessary files is compromised if the redundancy is set to anything >1 (or whatever recovery window the translates to).  So if I try and restore a database in either environment and RMAN can't find the necesary file(s) will it return a message asking where those files are?  ...at which point i would call the sys admins to restore the particular file.  or would i be hosed?

thank you very much for any responses.
(i plan on buying 9i rman soon but didn't want to wait on this)

chris

(wishing for dedicated tape drives)