Squashfs-ed knoppix

[kl522]

Below is a comparison of some of the interesting aspects of squashfs vs cloop when running on the ***SAME*** machine with 4G physical memory. Some details have been snipped for clarity :-

When using cloop kernel driver :-

# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/sda2              94G   33G   61G  36% /mnt-system
/dev/cloop            4.0G  4.0G     0 100% /KNOPPIX
/dev/loop0            2.4G  940M  1.5G  39% /KNOPPIX-DATA
....

# cat /proc/meminfo 
MemTotal:        3588864 kB
MemFree:         3005164 kB
Buffers:          112860 kB
Cached:           303956 kB
SwapCached:            0 kB
Active:           220000 kB
Inactive:         294008 kB
....

# ls -al /mnt-system/KNOPPIX/KNOPPIX
-rwxrwxrwx 1 root root 1546036015 2010-06-16 22:36 /mnt-system/KNOPPIX/KNOPPIX

Here is the corresponding information when using squashfs :-

# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/sda2              94G   33G   61G  36% /mnt-system
/dev/loop0            1.4G  1.4G     0 100% /KNOPPIX
/dev/loop1            2.4G  939M  1.5G  39% /KNOPPIX-DATA
....
# cat /proc/meminfo
MemTotal:        3588864 kB
MemFree:         2927872 kB
Buffers:          178880 kB
Cached:           329248 kB
SwapCached:            0 kB
Active:           187076 kB
Inactive:         414508 kB
....
# ls -al /mnt-system/KNOPPIX/KNOPPIX.sq
-rwxrwxrwx 1 root root 1453662208 2010-06-16 23:09 /mnt-system/KNOPPIX/KNOPPIX.sq

Summary :-
1. cloop registers the need to use 4G of virtual memory on /dev/cloop, whereas squashfs registers the need for 1.4 G of virtual memory on /dev/loop0

2. squashfs compressed image is smaller by 100M when using the same compression algorithm and block size.

Cheers.