Posts Tagged ‘qemu’

Mounting QEmu qcow2 Image using NBD

Sunday, March 28th, 2010

For some reason, I had to mount a QEmu qcow2 image in the host system. I googled around and found some post on the qemu-dev list. Also, the QEmu FAQ answers whether one can mount any QEmu image, but it’s not very verbose. So I went and tried and voila: It works :)


muelli@xbox:~$ qemu-nbd --read-only --partition=1  --snapshot  winxp.img &
muelli@xbox:~$ sudo nbd-client localhost 1024 /dev/nbd0
Negotiation: ..size = 31447206KB
bs=1024, sz=31447206
muelli@xbox:~$ sudo mount /dev/nbd0 -oloop  ~/empty/
muelli@xbox:~$ ls -l /home/muelli/empty/
total 1744981
-rwxrwxrwx 1 root root         0 2009-03-13 18:35 AUTOEXEC.BAT
-rwxrwxrwx 1 root root      4952 2008-04-14 09:00 bootfont.bin
-rwxrwxrwx 1 root root       207 2009-03-13 18:27 boot.ini
-rwxrwxrwx 1 root root         0 2009-03-13 18:35 CONFIG.SYS
drwxrwxrwx 1 root root      4096 2009-03-13 19:17 Dokumente und Einstellungen
drwxrwxrwx 1 root root         0 2009-03-13 22:02 Driver
-rwxrwxrwx 1 root root 536399872 2009-04-04 14:37 hiberfil.sys
-rwxrwxrwx 1 root root         0 2009-03-13 18:35 IO.SYS
-rwxrwxrwx 1 root root         0 2009-03-13 18:35 MSDOS.SYS
drwxrwxrwx 1 root root      4096 2009-03-13 22:29 nlite
-rwxrwxrwx 1 root root     47564 2008-04-14 09:00 NTDETECT.COM
-rwxrwxrwx 1 root root    251712 2008-04-14 09:00 ntldr
-rwxrwxrwx 1 root root 805306368 2009-04-04 14:37 pagefile.sys
drwxrwxrwx 1 root root         0 2009-03-13 19:03 Postinstall
drwxrwxrwx 1 root root      4096 2009-03-13 20:59 Programme
drwxrwxrwx 1 root root      4096 2009-03-13 19:06 System Volume Information
drwxrwxrwx 1 root root     32768 2009-04-04 14:40 WINXP
muelli@xbox:~$

It uses a technology I’ve never heard of: Network Block Device (NBD). Now I’m a bit smarter. And I hope you can make use of this information :)