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IB2007 journals and archiving question


2008-03-07 04:35:26 PM
delphi213
Is it possible to produce "corrupt" journal files by using cached writes to
the journal files or by maybe a network connection loss while archiving the
journals over a network? If so, what happens if one recovers from the
corrupt journal files? Is the recovered database corrupt or will ib notice
the corrupt files and gbak stop recovering?
This questions came to my mind, because i have a server with a raid system,
and no possibility to put the journal file onto a drive, which is not
cached. Since there are no performance problems, it would be fine for me to
put the journals on a logical drive on the raid. I plan to archive the
journals periodicaly to a backup server over the network. Are there any
advices to use journals with raid systems?
Thanks in advance,
Michael
 
 

Re:IB2007 journals and archiving question

Michael Danninger writes:
Quote
Is it possible to produce "corrupt" journal files by using cached
writes to the journal files or by maybe a network connection loss
while archiving the journals over a network? If so, what happens if
one recovers from the corrupt journal files? Is the recovered
database corrupt or will ib notice the corrupt files and gbak stop
recovering?
InterBase will not cache writes to the journal files under any
circumstances. The big risk from caching comes from putting the
journals on a drive with a caching controller.
Quote

This questions came to my mind, because i have a server with a raid
system, and no possibility to put the journal file onto a drive,
which is not cached. Since there are no performance problems, it
would be fine for me to put the journals on a logical drive on the
raid. I plan to archive the journals periodicaly to a backup server
over the network. Are there any advices to use journals with raid
systems?
The journal files are sequential. When you recover IB reads the journal
file starting at the beginning and reads until it cannot read anymore
so my understanding is that you will recover what actually got written
to the journal.
--
Bill Todd (TeamB)
 

Re:IB2007 journals and archiving question

Michael Danninger writes:
Quote
impossible to corrupt
I will never use the phrase "impossible to corrupt" for any file on any
disk on any computer. The type of file that is least susceptible to
corruption is a sequential file and the journal files are sequential.
It is very very very very unlikely that a journal file will become
corrupt.
--
Bill Todd (TeamB)
 

Re:IB2007 journals and archiving question

Quote
InterBase will not cache writes to the journal files under any
circumstances. The big risk from caching comes from putting the
journals on a drive with a caching controller.

The journal files are sequential. When you recover IB reads the journal
file starting at the beginning and reads until it cannot read anymore
so my understanding is that you will recover what actually got written
to the journal.
So is it right, that the worst thing that can happen using a caching
controller is to loose the transactions in the cache, but that it is
impossible to corrupt the journal file, to which the cache should have been
written?
 

Re:IB2007 journals and archiving question

Quote
I will never use the phrase "impossible to corrupt" for any file on any
disk on any computer. The type of file that is least susceptible to
corruption is a sequential file and the journal files are sequential.
It is very very very very unlikely that a journal file will become
corrupt.
Thanks a lot for your answers, Michael