Subject RE: [firebird-support] Database for images
Author Rick Debay
> You must remember, we use FreeBSD...We can take a filesystem snapshot,
and spend as much time as we like doing a filesystem copy

If you are running LVM under Linux, then you can take snapshots of the
file system.

-----Original Message-----
[] On Behalf Of Nigel Weeks
Sent: Monday, May 07, 2007 12:45 AM
Subject: RE: [firebird-support] Database for images

> I think it's the first time i heard about someone using rsync to
> synchronize firebird databases. I would like to know more about your
> experience.

> - Did you measure if rsync is efficient to make its job in this case?
> I don't know FB internals, but after some thousands of transactions,
> is the database file in a state rsync can track its similarities and
> still optimize the transfers?

When it comes to keeping two files on different hosts, rsync absolutely
As you may know, it only copies the deltas (the changes) over the wire,
so if you've got a 30GB .fdb file, and you add one record, the only data
it will move over the wire are the parts of the file containing the new
record, and updated indexes, and any pages marked as bad/old/available
for re-use.

The ins and outs of it are outside the scope of this email, but
basically, it ensures the checksums of the file are identical - an exact
mirror image.

> - Do you really do this on live databases? Never had problems? Maybe
> if i lock the database (as if i would make a file copy) i could use
> this approach on windows/linux.

You must remember, we use FreeBSD - a very different beast to Windows
and Linux. We can take a filesystem snapshot, and spend as much time as
we like doing a filesystem copy of the .fdb from the server to anywhere,
and Firebird can happily continue on it's version of the filesystem.

Rsync simply enables us to drastically reduce the amount of data we need
to move across the network to the DR servers.

> - Is there someone doing this?

I doubt many people are. Most people think Linux and Windows are the
best choices available...




Visit and click the Resources item on the
main (top) menu. Try Knowledgebase and FAQ links !

Also search the knowledgebases at


Yahoo! Groups Links

Disclaimer: This message (including attachments) is confidential and may be privileged. If you have received it by mistake please notify the sender by return e-mail and delete this message from your system. Any unauthorized use or dissemination of this message in whole or in part is strictly prohibited. Please note that e-mails are susceptible to change. RxStrategies, Inc. shall not be liable for the improper or incomplete transmission of the information contained in this communication or for any delay in its receipt or damage to your system. RxStrategies, Inc. does not guarantee that the integrity of this communication has been maintained nor that this communication is free from viruses, interceptions or interference.