Incrementally Updated Backups (RMAN)
- From: Kumar Madduri <ksmadduri@xxxxxxxxx>
- To: oracle Freelists <Oracle-L@xxxxxxxxxxxxx>
- Date: Tue, 21 Jan 2014 02:38:07 -0800
Hello:
My understanding is that this seems to be the best combination in the sense
that it gives me a full backup (at a point in time) plus have the
advantages of incremental backup.
In case of incremental backups (differential or cumulative), restore may be
tricky or not possible depending on non-availability of a backup pieces (Of
course, catalog db/control file keeps track of backup sets that are needed
for recovery etc but if the unix sysadmins fail to backup the directories
holding a particular backupset or dba accidentally deletes a backupset then
it can be tricky).
In case of normal compressed backups (full), it gives me warm feeling that
a backup exists and I can apply archive logs to any point in time to do the
restore/recovery. But it takes up more time and storage space.
I find incrementally updated backups to be the combination that gives me
the best of both worlds (and also would save me time and storage place in
case of my database that has LOB data in it. The db is 1. 2 TB but only 500
GB redo is generated at most in 10 days ) with the only following drawback
- I would have only one good backup (with the default config ML note
745798.1) and so if I take backups on Monday 2:00 AM and Tuesday 2:00 AM, I
would not be able to roll forward fro Monday 2:00 AM to Monday 2 PM (for
example) on Wednesday. I could only do point in time recovery from time of
my latest incremental backup. I can do a level 0 backup a different time or
a full backup but that kind of defeats the purpose of having to save the
storage space.
- The other thing is if I use "Recover copy of database until time clause
sysdate -n" then I would have differential incremental backups till n days
before recover is applied and I would have the same challenge of trying to
maintain all the backup pieces till n days (i.e. t he same disadvantage or
inconvinience of having a incremental backup strategy)
These are probably actually not disadvantages but the way the program works
but I call them drawbacks for lack of another word
Are there any other pitfalls that I should be aware of if I want to
implement this as the only backup strategy i.e no more full backups or
incremental backups ?
Is this being implemented in this format else where?
Thank you and apologies for the long winded mail.
- Kumar
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