Re: [gentoo-user] What can I use for a compressed file system?

[ted leslie]

since you are not looking at writing to this fs,
then you can use cloop or squashfs

for example, gentoo uses squashfs for its live cd/dvd

squashfs is considered better, but both are in use on live cd/dvd, 
cloop was (At least partially) written by the knoppix dude.

typically you get 2.5:1 compression with these over a general linux distro file average.

either one will put all files starting at a root path into the compressed structure.
The only real difference between doing it cloop/squashfs and tar.*z
is that cloop/squashfs can be directly accessed (once mounted),
which might be of some use.

big negative (unless fixed in recent releases) is you need enough ram/VM to hold the entire
fs (to be compressed) in memory. So if you have 512MB ram and a 1GB VM allocation,
the biggest fs you can archive using cloop/squashfs would be 2.5GB (approx), that compresses down to 
the 1GB to fit into your VM. 

pretty recent cloop souce is at knoppix web site,
squashfs, IIRC is at kernel.org
squashfs would also be available in gentoo, as gentoo uses it in their live cd.

-tl

On Fri, 12 May 2006 02:47:56 -0500
Zac Slade <krakrjak@××××××××××.net> wrote:

> On Thursday 11 May 2006 19:51, W.Kenworthy wrote:
> > What can I use for a compressed file system?  I am looking at setting up
> > a loopback mounted filesystem that I want to use to store backups into.
> > Compression is needed as space will become a limitation in the future (I
> > want to do a whole system backup that so far is 2:1 compressed via
> > tar.bzip2.  I am thinking of using dirvish into a compressed loopback
> > mount - but how do I set up a compressed fs?
> Have you tried reiserfs?  As long as it is NOT mounted with the "notail"
> option it can sometimes save 50% on space compared to ext3/jfs/xfs depending
> on your usage.
>
> There is also a possiblility of using LVM2 snapshots also if you have LVM2
> devices already set up.  I'm not sure how dirvish is for backup and I'm not
> sure how good a loopback backup to a file really is anyway.  That depends on
> the consistency of at least a partition anyway.  Maybe you are trying to
> solve the wrong problem?
>
> --
> Zac Slade
> krakrjak@××××××××××.net
> ICQ:1415282 YM:krakrjak AIM:ttyp99
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> gentoo-user@g.o mailing list
>
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