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From Justin Swanhart <>
Subject Re: Backup strategies
Date Wed, 27 Oct 2004 16:17:19 GMT
I would suggest that you create a lock file for your index writing
process, if the lock file is encountered close the IndexWriter until
the lock file is removed.  After you create the lockfile, wait a few
seconds to make sure the writer process has quiesced, then create a
snapshot of the filesystem.  Remove the lockfile and backup the
snapshot with your favorite backup tool (exclude the lock file), then
drop the snapshot.


On Wed, 27 Oct 2004 14:40:20 +0200, Christoph Kiehl <> wrote:
> Christiaan Fluit wrote:
> > I have no practical experience with backing up an online index, but I
> > would try to find out the details of the write lock mechanism used by
> > Lucene at the file level. You can then create a backup component that
> > write-locks the index and does a regular file copy of the index dir.
> > During backup time searches can continue while updates will be
> > temporarily blocked.
> The problem with this approach is that this will not only block write
> operations but you will get timeouts for these operations which will
> lead to exceptions. To prevent this you must implement some queuing,
> which is what I would like avoid.
> Regards,
> Christoph
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