Hi John, > Hello, all. In our earlier deployments on kernel 2.6.22, we were very > happy with the results of vhashify. For some reason, our use in > 2.6.27.14 using vserver 2.3.0.36.4 does not seem to be working as well. > This is important to us because we are planning roughly 400 nearly > identical guests on this one host. > > We currently have 10 Ubuntu 8.0.4 guests running on our CentOS 5.2 based > host. Each one is roughly 2GB in size and were all cloned from the same > template. Total storage on the vserver partition is roughly 21GB. The > only unusual bit about this installation is there is /vservers/vetc > directory which is then mounted via bind to /etc/vservers. This was > originally because there was a single encrypted partition mounted via > iSCSI holding all the vserver information. > > We've done: > mkdir /etc/vservers/.defaults/apps/vunify/hash /vservers/.hash > ln -s /vservers/.hash /etc/vservers/.defaults/apps/vunify/hash/root > > We noticed there is another > link, /etc/vservers/.defaults/apps/vunify/hash/00 > and hashify complained of a duplicate "root"directory so we deleted the > root symlink. With or without it, we have the same results. are there any hardlinks visible inside the /vservers/.hash directory? If not the hashify did not work. You can check which files inside the vservers are not unified by running find /vserver/<guest> -type f -links 1 and the unified files by running: find /vserver/<guest> -type f -links +1 This should give you a hint if vhashify worked correctly. > For each vserver guest, we did: > mkdir /etc/vservers/<name>/apps/vunify > > Has something changed with 2.6.27.14? AFAIK unification is just done in userspace it should not depend on the kernel version. Just the copy-on-write-link-breakage is done in the kernel. > Are these realistic numbers? Does not seem realistic to me. > I > would think ten identical systems should yield just slightly more than > the space of one system after running hashify. I would guess something with your .hash directories is not setup correctly and therefore the hashify did nor work as expected. You can try to fix this and then just run: vserver <guest> hashify on a running guest. I have setup unification successfully here and used this two wiki pages as howto: http://linux-vserver.org/Frequently_Asked_Questions#Unification http://linux-vserver.org/util-vserver:Vhashify Hope this helps, Christoph