Bug#552665: RFP: Zumastor -- Zumastor is Free software that adds enterprise storage features (primarily improved snapshots and remote replication) to Linux.
Package: wnpp
Severity: wishlist
* Package name : Zumastor
Version : 0.8
Upstream Author : Dan Kegel <dan@kegel.com>
* URL : http://zumastor.org/
* License : (GPL)
Programming Lang: (C, C++, C#, Perl, Python)
Description : Zumastor is Free software that adds enterprise storage features (primarily improved snapshots and remote replication) to Linux.
It has been difficult to convince users of commercial NAS applicances to switch to Linux. In particular, some commercial NAS boxes have had better support for snapshots and remote replication than Linux does. Zumastor is an effort to fix that.
2.1. Snapshots
Snapshots can be useful as part of an hourly backup system. Instead of shutting down all applications for the entire duration of the backup, you can shut them down for just the second or two needed to take a snapshot.
If your goal is to protect users from accidental deletion of files, you may want to take snapshots every hour, and leave the last few snapshots around; users who accidentally delete a file can just look in the snapshot.
LVM already lets administrators create snapshots, but its design has the surprising property that every block you change on the original volume consumes one block for each snapshot. The resulting speed and space penalty usually makes the use of more than one or two snapshots at a time impractical.
Zumastor keeps all snapshots for a particular volume in a common snapshot store, and shares blocks the way one would expect. Thus making a change to one block of a file in the original volume only uses one block in the snapshot store no matter how many snapshots you have.
2.2. Remote Replication
Andrew Tridgell's rsync is a wonderful tool for replicating files remotely. However, when doing periodic replication of large numbers of infrequently changing files, the overhead for figuring out what files need to be sent can be extreme.
Zumastor keeps track of which block change between one snapshot and the next, and can easily send just the changed blocks. Thus Zumastor can do frequent replication of large filesystems much more efficiently than rsync can.
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