...I have a
cron job from the production database that runs every 5-10min to check
if there are any new archive logs and copy new archive logs to the
remote stand by failover machine.
The problem with this scenario is that there might be a possibility that
I might scp a partially filled archive log over to the remote machine on
a heavily updated databases with batch jobs runnings most of the time
like ours.
So, inorder to over come this we want to change the archive_command to
archive_command = 'cp %p /archives-temp/%f && mv /archives-temp/%f
/archives/%f'
( I could do remote copy also with the command but I dont want to go
that route because of network problems. )
....
My question is there any problem in using this approach ? will I run
into problems in the future ? are there any other better ways of solving
this problem ?
Looks like it should work but have you considered using rsync instead?
If the file grows from one pass to the next, rsync will send the
differences.
Given the small number of files (at least far fewer thatn the
half-million file trees my rsyncs process every 10 minutes) in the
archive directory, rsync will probably only take a fraction of a second
to determine whether or not any transfers are needed. I'll bet that you
could run rsync every 15 seconds with virtually no increase in system
load other than whatever is required to transfer the data and you have
that load already.
Rsync can also handle deleting files from the receiving end if you wish.
I am starting to work on a wal-shipping backup and I plan to try rsync
first.
Some advice. I make extensive use of rsync. The core skeleton of my
scripts goes something like this:
cd /the/appropriate/place
if [ -f rsync.lockfile ]
# Exit - new pass started before previously
# started rsync completed
exit
fi
date > rsync.lockfile
rsync <your parameters as appropriate>
rm rsync.lockfile
I run another script on the target machine that periodically checks the
age of rsync.lockfile and sends alerts if it is excessively old (where
excessive will be determined by the specifics of your setup - I use one
hour).
Cheers,
Steve
