Re: [Xen-users] Lost images..

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Thu, 2014-06-26 at 15:47 +0200, Stephan Viljoen wrote:
> Ok , I think I understand now. 
> 
> 2354 ?        Sl     3:36 /usr/lib/xen/bin/qemu-dm -d 4 -serial pty 
> -domain-name test-01 -videoram 4 -k en-us -vnc 0.0.0.0:0 -vncunused -M xenpv
> So if the domains runs under PID 2354 for instance , then I should be able to 
> recover the image from the following folder ?
> /proc/2354/fd 
> 
> Here's the content of the directory , how do I actually go about recovering 
> the actual disk image ?

I was expecting one of those things to be a link to the filesystem
image. But I don't see it, so it may be that this qemu process is not
providing disk services (just other stuff).

What version of Xen are you running? What toolstack? and what does your
domain cfg file contain? Can you also post the output of "xenstore-ls
-fp".

Ian.


> 
> dr-x------ 2 root root  0 Jun 26 15:46 .
> dr-xr-xr-x 8 root root  0 Jun 26 15:45 ..
> lr-x------ 1 root root 64 Jun 26 15:46 0 -> /dev/null
> l-wx------ 1 root root 64 Jun 26 15:46 1 -> /var/log/xen/qemu-dm-test-01.log
> lrwx------ 1 root root 64 Jun 26 15:46 10 -> /proc/xen/xenbus
> lr-x------ 1 root root 64 Jun 26 15:46 11 -> pipe:[14474]
> l-wx------ 1 root root 64 Jun 26 15:46 12 -> pipe:[14474]
> lrwx------ 1 root root 64 Jun 26 15:46 13 -> /proc/xen/privcmd
> lrwx------ 1 root root 64 Jun 26 15:46 14 -> /dev/xen/evtchn
> lrwx------ 1 root root 64 Jun 26 15:46 15 -> /dev/xen/gntdev
> lrwx------ 1 root root 64 Jun 26 15:46 16 -> /dev/ptmx
> lrwx------ 1 root root 64 Jun 26 15:46 17 -> /dev/xen/evtchn
> lrwx------ 1 root root 64 Jun 26 15:46 18 -> /dev/xen/evtchn
> lrwx------ 1 root root 64 Jun 26 15:46 19 -> socket:[15403]
> l-wx------ 1 root root 64 Jun 26 15:46 2 -> /var/log/xen/qemu-dm-test-01.log
> lr-x------ 1 root root 64 Jun 26 15:46 20 -> pipe:[15405]
> l-wx------ 1 root root 64 Jun 26 15:46 21 -> pipe:[15405]
> lrwx------ 1 root root 64 Jun 26 15:46 25 -> 
> /var/run/xend/dm-4-1403189404.fifo
> lr-x------ 1 root root 64 Jun 26 15:46 3 -> pipe:[14469]
> l-wx------ 1 root root 64 Jun 26 15:46 4 -> pipe:[14469]
> lrwx------ 1 root root 64 Jun 26 15:46 5 -> /proc/xen/privcmd
> lrwx------ 1 root root 64 Jun 26 15:46 6 -> /proc/xen/xenbus
> lrwx------ 1 root root 64 Jun 26 15:46 7 -> /dev/ptmx
> lrwx------ 1 root root 64 Jun 26 15:46 8 -> /var/run/tap/qemu-read-4
> lrwx------ 1 root root 64 Jun 26 15:46 9 -> /var/run/tap/qemu-write-4
> 
> 
> 
> 
> -----Original Message-----
> From: xen-users-bounces@xxxxxxxxxxxxx 
> [mailto:xen-users-bounces@xxxxxxxxxxxxx] On Behalf Of Ian Campbell
> Sent: Thursday, June 26, 2014 2:58 PM
> To: Stephan Viljoen
> Cc: xen-users@xxxxxxxxxxxxx
> Subject: Re: [Xen-users] Lost images..
> 
> On Thu, 2014-06-26 at 14:41 +0200, Stephan Viljoen wrote:
> > I just made one hell of screw up by accidently deleting the wrong 
> > folder containing all my xend domain images. Now the strange part is , 
> > all those hosts are still alive and thankfully Iâm able to make 
> > backups for the content so I was wondering whether thereâs a way to 
> > somehow restore the images?
> 
> If this were happening with normal processes (i.e. you've deleted a file 
> which some process has open) then you'd be able to recover it via 
> /proc/$PID/fd.
> 
> So if the domains are using a userspace process as a disk backend (e.g.
> tapdisk or qdisk) then you could probably apply that technique to the backend 
> processes.
> 
> If the domains are using loop+blkback then I guess you might find the content 
> in /dev/loop*.
> 
> If the domains are using just blkback directly then I think you might be 
> stuck, or at least I don't know what to suggest. You said folder of images so 
> I'm hopeful you don't fall into this case.
> 
> Ian.
> 
> 
> 
> 
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> Xen-users mailing list
> Xen-users@xxxxxxxxxxxxx
> http://lists.xen.org/xen-users
> 



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