[DRBD-user] DRBD as a "backup" System

Leroy van Logchem leroy.vanlogchem at gmail.com
Fri Nov 11 21:48:55 CET 2005

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.

Using that method has one or more problems. All new data since last
sync will be invisible or even lost if you resync the old to the new

The best paper of USENIX 2004 details the use of the userland
filesystem called FUSE.

"Abstract - In a typical file system, only the current version of a
file (or directory) is available. In Wayback, a user can also access
any previous version, all the way back to the file's creation time.
Versioning is done automatically at the write level: each write to the
file creates a new version. Wayback implements versioning using an
undo log structure, exploiting the massive space available on modern
disks to provide its very useful functionality. Wayback is a
user-level file system built on the FUSE framework that relies on an
underlying file system for access to the disk. In addition to
simplifying Wayback, this also allows it to extend any existing file
system with versioning: after being mounted, the file system can be
mounted a second time with versioning. We describe the implementation
of Wayback, and evaluate its performance using several benchmarks."

And others are in the making, mostly called log structured filesystems
or lossless filesystems.
In-progress is: http://www.nilfs.org/current_status.html


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