[Dirvish] [PATCH] btrfs support

Adrian von Bidder avbidder at fortytwo.ch
Sun Dec 12 15:43:20 UTC 2010


Heyho!

Please consider the attached patch. (against 1.2.1)

Storing the dirvish trees in btrfs snapshots instead of using rsync's --
link-deest option makes sense, IMO, because:

 * vastly accelerated dirvish-expire ("btrfs subvol delete" is a constant 
time operation independently of how big the tree is)
 * uses less disk space (and, but I didn't benchmark this, potentially 
should be faster) because a copy on write snapshot is smaller and can be 
created in O(1) time compared with a hardlinked directory tree.
 * protection from accidental modification of a file in a tree (stupid, but 
it happens ...)
 * using rsync --inplace: takes advantage of btrfs' copy on write for files 
that have modified portions and portions that have stayed the same.

Long term: content deduplication for btrfs filesystems probably will be 
written sooner or later, when space savings through btrfs' copy on write 
pages for backups of multiple similar trees will become even more 
interesting.

I've written it basically for the first two reasons and because I really 
like the possibilities offered by btrfs...

cheers
-- vbi

-- 
How to overclock the board to the attachment from Windows?

You should telnet from the floppy disk and from the tools menu inside
Netscape you either never have to log from the POP3 miditower, or can't
debug a clock of a OpenGL file of a software of a BIOS in order to
explore the editor.
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