[CentOS] CentOS and LessFS

Nataraj incoming-centos at rjl.com
Wed Jan 18 00:41:24 UTC 2012

On 01/17/2012 03:36 PM, Les Mikesell wrote:
> I wouldn't trust any of the software block-dedup systems with my only
> copy of something important - plus they need a lot of RAM which your
> old systems probably don't have either.

I am interested in backuppc, however from what I read online it appears
that zfs is a very featureful robust  high performance filesystem that
is heavily used in production environments.  It has features that allow
you to specify that if the reference count for a block goes above
certain levels it should keep two or three copies of that block and that
could be on separate storage devices within the pool.  It also supports
compression.  With backuppc deduplication, your still hosed if your only
copy of the file goes bad.  Why should block level deduplication be any
worse than file level deduplication?

Furthermore, zfs has very high redundancy and recovery ability for the
internal filesystem data structures.  Here's a video describing ZFS's
deduplication implementation:  http://blogs.oracle.com/video/entry/zfs_dedup

At this point I am only reading the experience of others, but I am
inclined to try it.  I backup a mediawiki/mysql database and the new
records are added to the database largely by appending.  Even with
compression, it's a pain to backup the whole thing every day.  Block
level dedup seems like it would be a good solution for that.

I'm not a big fan of Oracle, but from a technical standpoint zfs sounds
quite good.  I'm thinking of trying it on my laptop, because it's
supposed to work well for storing things like virtual machines, and if a
decent implementation runs on CentOS, Why not?

Les, do you run backuppc on ext3 or ext4 filesystems?  I remember a
while back, someone saying that a filesystem with more inodes was
required for substantial backuppc deployment.


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