Currently, I'm using a server as an online backup and to run some VMs with VMware Server. I'm interested in converting it to VMware ESXi but have some concerns about the possible corruption of my VMDKs if I choose to store my data on them. I was also thinking of storing the data directly on the datastore but can't find any way to mount a VMFS volume with a LiveCD if ESXi is unable to start.

What are my options? Is continuing to use VMware Server is a good idea, knowing that I DO want to use the server for both virtualization and backup purposes.


EDIT: Apparently, I wasn't clear enough. I have offline backups as well. VMs running on this server aren't important, backed up elsewhere and are just here to handle non-critical services.

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    Re-reading the original and then additional comments I see what you are doing and actually do the same thing. I have a Linux host running VMware Server for some mildly important VMs. I also carved up more of the host drive space to provide backup storage for some critical machines. Finally, to get the absolute maximum use due to budget constraints, I have one more section of host drive space carved out for shared storage among several of the VMs. It's all quite nasty, but does work. I'd encourage you to think about what is the most important aspect of your system and design for that. – Keith Stokes Jan 31 '11 at 1:27
  • My guests are backed up to other servers. However, the drawback for me is that I'm having to run an inefficient host system in order to serve my other needs. That's the design tradeoff I had to make. Yours may not be the same thing if your guests are less important. – Keith Stokes Jan 31 '11 at 1:30

I'd suggest that there's MORE chance of vmdk corruption using 'server' than ESXi as it has a very small HCL specifically to ensure that drivers are as stable as possible. I've got 24,000 'host-hours' with ESX/i and have never seen any vmdk corruption caused 'in flight'. If you needed to get the data off a VMFS3 disk you could always just mount it as a secondary disk on another ESXi host and copy/move it as usual.

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  • Actually, my backup isn't on a VMDK but on the ext3 partition of the server. Last month, the server (hosted in a datacenter) unexpectedly rebooted with no damage to my data but I'm not sure if I'll be that lucky with a VMDK-based storage on ESXi. I guess that if you advise me to mount the disk to another machine, it's because there's no VMFS driver freely available and dd is my only solution remotely, right? – Laurent Nominé Jan 30 '11 at 19:23
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    Yeah, VMFS is a proprietary file system so there's not generic drivers for it. I don't understand your concern to be honest, maybe because I've a good deal of experience with ESX/i but honestly you don't need to worry, I've never seen anything to worry me that wasn't caused by the same sort of catastrophic error that could affect any file system. – Chopper3 Jan 30 '11 at 22:18
  • +1 Chopper's answer and comment. Can I just add that you should be backing this stuff up somewhere 'offline' if it is that important to you anyway, Laurent? Not because of any un-reliability in any of the VMWare products you mention but purely because sometimes stuff just happens? The answer isn't to worry about how to mount VMFS in the event of a DR, the answer is to have proper backups. And that's the answer regardless of what filesystem you use for your VMs. – Rob Moir Jan 30 '11 at 23:28
  • It seems that I've forgotten some details, sorry for that. I DO have offline backups, on this server there are just copies of them in case of a disaster (like fire in the building, etc) My goal is to know the most reliable way of storing these copies of backups. On a VMDK or directly on the datastore. – Laurent Nominé Jan 30 '11 at 23:44
  • Let's put it this way. You have offline backups and want to rent a server to have online backups too. There's plenty of storage and a very good CPU. You say to yourself: "Hey, it would be very nice to use this power to run some non-critical VMs." Considering that ESXi is your choice, how would you store your online backup? :) – Laurent Nominé Jan 31 '11 at 0:15

No matter what, you should have backups of your VMs on a separate box. Otherwise you are guaranteed to have grief at some point.

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  • Yes, it's already the case. These backups are not related to the VMs running on the server. – Laurent Nominé Jan 30 '11 at 23:25

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