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We are running multiple web, database, and application servers which usually share a pretty common installation (gentoo linux) and similar configuration in VMware ESXi 4. The differences are usually only some installed features or differing component versions. To create a new server, I usually choose the most similar (by features) running server, rsync a copy of it into freshly mounted filesystems, run grub, reconfigure and reboot.


Over time this duplicates many on-disk data blocks which probably sums up to several 10's of gigabytes. I suppose if I could use a base system as template with the actual machines based on top of that, only writing changed blocks to some sort of "diff image", performance should improve (increased cache hit rate) and storage efficiency should increase (deduplicated storage space). This would be similar to what ESXi already supports for RAM deduplication (page sharing).


Is there any way to easily do this on ESXi 4? I already share the portage tree via NFS but this would not work for the rootfs.

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Not via ESX/i itself no - but you could choose to create your datastores on a SAN that does the dedupe itself of course.

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What about shared disk images? I see I can set a scsi disk to shared mode in the vm setup. – hurikhan77 May 19 '10 at 11:03
yes, but what's going to do the dedupe - it's not a function of ESX/i. – Chopper3 May 19 '10 at 11:21
Well, we do not actually need a full dedupe, more sort of "incremental growth" would be sufficient. – hurikhan77 Jun 3 '10 at 9:06
Well you can use 'Thin Provisioning' for your .vmdk's - basically you tell the VM that it has say 20GB but if it only uses 2GB then you only store 2GB, maybe this is what you want - be aware though that if you don't have enough space and the VM DOES want to use all 20GB then you can kill your VM. – Chopper3 Jun 3 '10 at 9:55

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