[pybsddb] Snapshotting / replicating bdb

[Jesus Cea]

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Cameron Simpson wrote:
> I would point out, in case it wasn't made clear in an earlier post, that
> like copying filesystems, copying database files shoud be surrounded by
> some sort of sync function:
> 
>   db.freeze()
>   ...copy/snapshot the db...
>   db.unfreeze()

This is a good advice in general. But current databases have procedures
to do a hot-backup in a safe way, simply because you can not stop
database operations for the hours it take to copy a multi-terabyte
database environment.

Working with BerkeleyDB, you have a couple of options:

1. Working with snapshots+cloning (ZFS), I simply clone the database and
then do a database recovery over the clone. Of course the BDB
environment must be transactional. This is very fast. And safe (if the
database is transaction protected).

2. If you need to physically copy the data, use the "hotbackup"
procedure clearly explained in Berkeley DB documentation.

- --
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