lrzip does not work on device files

All other questions
xerces8
Posts: 28
Joined: 28 Aug 2012, 11:17

lrzip does not work on device files

Postby xerces8 » 25 Jul 2016, 12:29

Hi!

Did anyone try using lrzip to compress a device file, like /dev/sda?
For example: lrzip /dev/sda -o /mnt/backup/sda.compressed

For me it just creates a 66 byte big file that decompresses to a file with 0 length.

I'll try it with other distros later, in the meanwhile I'm interested in other users experiences.

I did my tests running sysrescd v4.8.0 having lrzip v0.621
kernel:
Linux version 4.1.27-std480-amd64 ([email protected]) (gcc version
4.8.5 (Gentoo 4.8.5 p1.3, pie-0.6.2) ) #2 SMP Thu Jun 30 13:18:43 UTC
2016

Regards,
David

gernot
Posts: 1127
Joined: 07 Apr 2010, 16:19

Re: lrzip does not work on device files

Postby gernot » 26 Jul 2016, 04:23

Look like lrzip read the size if the device node self.
You can verify this with strace.

Try compressing with lrzip < /dev/sda -o /mnt/backup/sda.compressed

Gernot

xerces8
Posts: 28
Joined: 28 Aug 2012, 11:17

Re: lrzip does not work on device files

Postby xerces8 » 26 Jul 2016, 13:39

Thanks for the insight.

lrzip needs access to the entire file to be efficient. (stdin works too, but in a limited mode)

I'll discuss the issue with upstream.

xerces8
Posts: 28
Joined: 28 Aug 2012, 11:17

Re: lrzip does not work on device files

Postby xerces8 » 26 Jul 2016, 13:56



Return to “Other”

Who is online

Users browsing this forum: No registered users and 2 guests