Opinions on choosing the right network storage
 

I'm looking to run a couple of VMware servers and store their data on network storage of some sort instead of on the servers themselves. (This makes it easier to take snapshots of both machines at once, plus it has a much higher capacity.)

What I'm thinking at the moment is creating an LVM volume on the file server out of raided drives and exporting it. I've used both NFS and Samba (CIFS?) before on little home projects, but this is eventually going to become a production setup and I'd like to get it right the first time.

NFS from what I've seen is pretty terrible and insecure, plus it can lock up the machine that it's exporting to, so I'm leaning towards CIFS right now. But isn't CIFS more for Windows networking?

I guess what I'm looking for is general opinions on this subject that I have virtually no experience in. :)

If your NFS is insecure, you have set something up very wrong. Normally it is far more secure and stable than Samba every thought about. I also find it much faster than Samba.

I would also avoid LVMs unless you absolutely have to. LVMs are fine, until the blow up. When they blow up they are just one more layer of complexity that you have to deal with in order to repair things, they can be a royal PITA. For non raid systems you can accomplish most of the advantages of LVM just by choosing where you mount points are placed(a drive can appear as just another sub directory). The one thing that you cannot do this way is have contiguous space(one single file across multiple drives). On raid arrays (which are generally seen as one big drive already) there really is no advantage to going to LVM.

Thanks for the reply.

I'm with you on LVM being an extra layer of complexity. The reason I'm considering it is so that I can take filesystem snapshots of the VMs before backing them up with rsync to another server -- basically, I want the data to be consistent. If rsync can handle copying a bunch of live 2GB files (which is what VMware's data is) without any issues, I'll happily ditch LVM.

As for NFS: I'm just going by what I've read. :)

I've had systems frozen by disconnected NFS shares, though. That much I can say from personal experience, and it's contributing to my bias against using it in a production system.

How is using a LVM going to effect how you backup your data? You run the same file system (EXT3 or whatever) on top of the LVM as you run on a drive or a raid array. rsync's ability to do what you want should be independent of using LVM. Not sure by any means, but the LIVE part may raise some issues on doing backups of VMs. I suspect that you may have to back them up just like a normal (non VM) system.

Again, freezing on disconnects sounds like a misconfiguration issue.

You can run samba/CIFs on linux. But remember you will lose all your permissions on those files(they will become just like windows files).

As a side note you can also use NFS on windows, you just have to get M$'s unix toolkit(I think that is the name). Oddly enough they do not charge extra for the toolkit.

Because LVM has a snapshot feature -- I'd take a snapshot of the volume where the VMs are running and copy that, instead of the live volume. That's just my current thinking, it's not written in stone or anything.

Maybe. Its been a few years since I tried it last (2006 I think), it's entirely possible that it was either me doing something wrong, or a bug in something I was using at the time. I'll definitely try to reproduce the freezing thing in a modern system.

For the sake of thoroughness I tried to reproduce the NFS freezing that I was talking about. As expected, when the NFS server stops responding for any reason -- interface goes down, it gets shutdown/suspended -- anything on the client trying to use the mountpoint will hang indefinitely. Even tab completing the mountpoint will cause a hang.

I'm not expecting it to work if the server gets shutdown, but it'd be nice if the client handled it more gracefully than just freezing. On the plus side, everything seems to fix itself when the server comes back up.

How are you mounting it becuase it should not freeze like that, mine do not.

mount 192.168.1.207:/export /mnt/nfs

Slackware 12.2 server, Ubuntu 8.10 client

/etc/export on the server:

/export 192.168.1.0/255.255.255.0(rw)

Ok you are missing part of your mount. Maybe something more like this:

Obviously changing the parameters to what your needs require, but telling it that it is nfs is important. You might also want to look at "man nfs" especially the retry=n section (if the above does not cure the issue).