Comment 1 for bug 747068

> ((Ok, this is the first time every I file a bug, so give me also
> feedback when I report wrong..))

Thanks for taking the time to report this bug.

> First of all, I want to build a system for production in wich I can build (very) fast new VM's.
> I installed Ubuntu Server 10.04.2 64Bit as host OS with the following partitions:
>
> /Boot [Prim] 1GB (EXT4)
> / [Prim] 25GB (EXT4)
> swap [Prim] 25GB (swap)
> ---extended---
> /tmp [Logical] 25GB (EXT4)
> /var/log [Logical] 10GB (EXT4)
> lvm [Logical] 1,5TB (lvm)
>
> When I use VMBuilder and build to a RAW logica volume (lvm), it takes more than 12 minutes!

I'd recommend building a single pristine image (where time to build doesn't matter), and
snapshot or copy that when you need a new image and make the few changes you need to.

Maybe that was your plan all along, but since you mention the time it took to make the
first image, I wasn't sure.

> Then I tried to change the /tmp partition (of the HOST) to EXT3 and it did take less than 4 minutes!!!!

Interesting.

Are you using a local archive mirror? It's possible that if you switch back
to ext4 now it'll go much faster.

> The only problem now is that the VM gives the following error on startup:
> EXT4-fs error (device sda1): ext4_mb_generate_buddy:
> EXT4-fs group 2: 3431 blocks in bitmap, 3597 in gd
>
> Any ideas?

Is sda1 your tmpfs? If so, edit your fstab to mark it as ext3.

> Maybe first any ideas for a workaround?

Actually long-term for most image building we recommend switching to live-build. If you try that, and your host has enough memory (more than 4G), then building out of a tmpfs can make for very fast, 2-4 minute, image builds. Please feel free to ask for help on irc on freenode#ubuntu-server or on the ubuntu-server mailing list.