Arch Linux

ying

Member

From: Austria

Registered: 2010-03-02

Posts: 110

Searching for a read/writeable filesystem similar to squashfs

Hi
I am searching for a virtual filesystem, which is mountable, compressed and has read and write access. I tried the tool archivemount with a tar archive, but I could not remount the mountpoint with aufs. I don't want a normal filesystems written with dd in a file, because I don't want to set a fixed size. It should dynamical adjust its size. I also don't want to use a sparse filesystem, because when it gets copied it isn't any more dynamical.

kjslag

Member

Registered: 2009-11-03

Posts: 43

Re: Searching for a read/writeable filesystem similar to squashfs

this may not be what you want, but:

btrfs supports compression (and read/write of course)
online volume growth and shrinking is supported (if that's not enough, you could use it with LVM for real dynamic size)

dmillard

Member

From: /dev/pts/0

Registered: 2010-04-02

Posts: 22

Re: Searching for a read/writeable filesystem similar to squashfs

I tried the tool archivemount with a tar archive, but I could not remount the mountpoint with aufs.

Could you describe what exactly you did with archivemount?  archivemount behaves erratically when run as root.  Try mounting as non-root to a directory you own.

I also don't want to use a sparse filesystem, because when it gets copied it isn't any more dynamical.

By sparse filesystem, I assume you mean a zeroed file mounted with a loop device?  As I understand it, this has problems shrinking, because removed data is not zeroed out. (This can be overcome by using "shred -uzn0 file" instead of "rm file".)  In addition, as long as such a file is copied to a filesystem that supports sparse files, it will still be dynamic.

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"Cleverness is not wisdom." ~Euripides