Compressed filesystem

Carnildo · Guru Joined: 17 Jun 2004 Posts: 594

Is there such a thing as a compressed filesystem for Linux, similar to the old MS-DOS "DoubleSpace" software?

BradN · Posted: Thu May 01, 2008 11:41 pm Post subject:

Short answer: not that I'm aware of

Longer answer: Yes (squashfs), but it's read-only after it's initially created. It's great for livecd's but it's probably not what you're looking for.

timeBandit · Posted: Fri May 02, 2008 1:02 am Post subject:

Another answer: Yes. See FuseCompress.
The forum thread is pretty old but the filesystem is still alive--the homepage shows an update released just last month. Can't tell you whether it's any good.
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tarpman · Posted: Fri May 02, 2008 7:53 am Post subject:

There is also the compression plugin for reiser4.
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kernelOfTruth · Posted: Fri May 02, 2008 10:14 am Post subject:

nick24 · n00b Joined: 10 Nov 2007 Posts: 24

I think that squashfs can be useful in certain situations. There's a nice guide on how to use squashfs and unionfs to shrink your portage tree tenfold in the Gentoo Wiki. It wouldn't be the best idea for compressing your whole filesystem at once, because it readonly and must be recreated after you edit it. Still, it has a very good compression ratio for the amount of processor time needed to extract it, and increases disk throughput and cache effectiveness because less data has to be read.

Here's the Wiki guide URL: http://gentoo-wiki.com/HOWTO_VERY_small_Portage_Tree_with_SquashFS_and_UnionFS

I also use it for backups because if a partition is wiped out I can simply mount the squashfs over it without dealing with long tarball extractions. It is also conveniently stored in a file under another filesystem, which means you can have a whole bunch of virtual squashed partitions without repartitioning.

BradN · Posted: Wed May 14, 2008 12:23 am Post subject:

I've used squashfs sucessfully to make a < 200MB "neutered" gentoo install for old 586/686 systems sitting around that can do X+firefox+abiword+pidgin and a few other smaller things. It's neutered in the sense that compilation can no longer be done on the target system - instead there's a chroot install on my main machine where it's updated, then rsync'd over.

(the main details are that just /usr is squashfs'd, and there are tons and tons of excluded files/directories when building the squashfs and rsyncing the root partition)