[Libguestfs] [ovirt-users] OVA import of FC21 VM hangs during virt-v2v conversion?

[Derek Atkins]

Hi,

On Wed, November 16, 2016 11:10 am, Richard W.M. Jones wrote:
>
>> It eventually did complete, after several hours.  But I don't understand
>> why this particular VM took so long when others (with similar disk
>> sizes/usages/configurations) completed in only 1-2 minutes.  Each VM is
>> effectively exactly the same (it's a build slave), so it's just the
>> basic installation of the particular Fedora release, the build tools,
>> and the build slave configuration.  Beyond the underlying fedora release
>> version, the systems are configured exactly the same.
>>
>> I migrated four similar VMs.  Three of them completed almost
>> immediately.  The last too much longer.  The ONLY thing different about
>> the one that took longer was that I decided to pack the disk first, so I
>> ran:
>>
>>   vmware-toolbox-cmd disk shrink /
>
> I'm not familiar with this command.  In general terms, conversions
> take a time proportional to the amount of disk space in use by the
> guest.

This command is a disk defragment + shrink inside VMware.  Basically, the
.vmdk was about 36G even though the system was only using about 3G. 
Running this command released all that free space and then reduced the
VMDK file.

I figured the time should be proportional to disk usage, which is why I
was so surprised that it took orders of magnitude longer than other
systems with similar disk usage (and indeed, in some cases the other
systems that completed in minutes had MORE disk usage).

> Running `virt-v2v -v -x ...' and observing the output will give you a
> good idea of what precisely it was doing for those hours.

Well, as I said in my original email, it was hanging at running setfiles:

commandrvf: stdout=n stderr=y flags=0x0
commandrvf: setfiles -F -e /sysroot/dev -e /sysroot/proc -e
/sysroot/selinux -e /sysroot/sys -r /sysroot -q
/sysroot/etc/selinux/targeted/contexts/files/file_contexts /sysroot/
Can't stat exclude path "/sysroot/selinux", No such file or directory
- ignoring.

There's no timestamp in the output or logs so it's hard to tell exactly
what happens when or how long each step takes.  For example, I wouldn't
know how long the setfiles step takes unless I sit there for hours
watching to see when it completes.  Is there some way to add timestamps to
each output line?

FWIW, here's the disk usage from within that VM:

Filesystem      Size  Used Avail Use% Mounted on
/dev/vda3        44G  4.6G   37G  12% /
devtmpfs        487M     0  487M   0% /dev
tmpfs           497M     0  497M   0% /dev/shm
tmpfs           497M  348K  496M   1% /run
tmpfs           497M     0  497M   0% /sys/fs/cgroup
tmpfs           497M  4.0K  496M   1% /tmp
/dev/vda1       969M  130M  773M  15% /boot
tmpfs           100M     0  100M   0% /run/user/1000
tmpfs           100M     0  100M   0% /run/user/0

For the record, Fedora 23, which imported in 2 minutes, has the following
disk usage:

Filesystem      Size  Used Avail Use% Mounted on
devtmpfs        486M     0  486M   0% /dev
tmpfs           496M     0  496M   0% /dev/shm
tmpfs           496M  536K  496M   1% /run
tmpfs           496M     0  496M   0% /sys/fs/cgroup
/dev/vda3        45G  7.9G   37G  18% /
tmpfs           496M  4.0K  496M   1% /tmp
/dev/vda1       969M  136M  767M  15% /boot
tmpfs           100M     0  100M   0% /run/user/1000
tmpfs           100M     0  100M   0% /run/user/0


> Rich.

-derek

>
>> in the VM prior to packaging it up as an OVA.  All the OVA files are
>> relatively small and similar in size:
>>
>> -rw------- 1 warlord warlord  1959553024 Nov  7 10:40 fc20-64.ova
>> -rw------- 1 warlord warlord  1794907648 Nov  7 12:27 fc21-64.ova
>> -rw------- 1 warlord warlord  2023595520 Nov  6 10:04 fc22-64.ova
>> -rw------- 1 warlord warlord  3381622272 Nov  5 16:18 fc23-64.ova
>>
>> The FC23 and FC22 migrations took the least amount of time, even though
>> they were the largest.
>>
>> > Rich.
>>
>> -derek
>>
>> --
>>        Derek Atkins                 617-623-3745
>>        derek at ihtfp.com             www.ihtfp.com
>>        Computer and Internet Security Consultant
>
> --
> Richard Jones, Virtualization Group, Red Hat
> http://people.redhat.com/~rjones
> Read my programming and virtualization blog: http://rwmj.wordpress.com
> virt-builder quickly builds VMs from scratch
> http://libguestfs.org/virt-builder.1.html
>


-- 
       Derek Atkins                 617-623-3745
       derek at ihtfp.com             www.ihtfp.com
       Computer and Internet Security Consultant