Thank you Philipp, I am using ext3 and your explanation makes sense. May I also ask if the qcow image automatically adjusts to the size or is it ever expanding image? I mean lets say I have 100 Gig and write 20 Gig on qcow ext3 image and then delete 10 Gig data. Would it show up as 120Gig or 110 once the deletion is done Thank you once again :) Jonah On Mon, Oct 24, 2011 at 3:17 AM, Philipp Hahn <hahn@xxxxxxxxxxxxx> wrote: > Hello Anonnymous, > > On Monday 24 October 2011 03:22:15 day knight wrote: >> I am not sure if this is the right behaviour but qcow2 image seems to >> grow when Centos is only formatting the image. I mean it goes upto 30 >> Gig once evrything is formatted and installed and it is minimal Centos >> install with no gui or apps just baseline. >> >> OS = Centos5 >> Virtualization: KVM >> Total Qcow2 Image Created = 1TB >> >> Once Centos is installed the qcow2 image shows as around 30 Gig. I >> have done several install and they were all less than 4 gig or even >> lesser but this seems to not make sense >> >> Can someone please explain what is going on? > > You didn't tell which file system you're using. ext3 needs to initialize its > meta data (super blocks, inote tables), which are scattered all over the > image. Depending on your cluster size fpr the qcow2 file, each (small) write > takes the space of a full cluster. Add to that the meta-data needed by qcow2 > itself (a two-level tree), 30 GiB seem to be okay. > > You might want to try ext4 with "delayed allocation" (IMHO enabled by > default), which doesn't write all over the range, since initialization of the > superblock and inode tables is delayed until they are acually needed. > > Sincerely > Philipp > -- > Philipp Hahn Open Source Software Engineer hahn@xxxxxxxxxxxxx > Univention GmbH Linux for Your Business fon: +49 421 22 232- 0 > Mary-Somerville-Str.1 D-28359 Bremen fax: +49 421 22 232-99 > http://www.univention.de/ > -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
