Can I create expandable volumes on my setup?
May 11, 2010 4:33 PM   Subscribe

I have a server with a Perc5/i RAID controller and 8 drive bays. I'd like to use it primarily as a storage server, with the idea of buying 4 drives now and expanding later. I'd like to put ESXi on the server and OpenFiler (or FreeNas) ontop of that. I don't need any drive redudancy (there's an attached tape controller), but I'd like to be able to pop in a new drive and expand it like you'd be able to do with LVM. Is this possible?

I'm not completely familiar with how ESXi handles storage and if this is even possible with my setup. This is a personal project, but I'd still like to not spend a couple weekends fooling around with this only to find out it is not possible. From the last time I played around in Linux, what I'm proposing seemed simple using LVM, but I know ESXi doesn't run Linux ... I'm not really familiar with how they deal with storage. If at all possible I'd like to be able to run a few VMs and not have this simply as an expensive OpenFiler box.

I'm open to creative ideas if it doesn't work out of the box (running ESXi off a flash drive and treating the RAID controller like a SAN?). I'm also open to other hypervisors, I'm just more familiar with VMWare.

Thanks!
posted by geoff. to Computers & Internet (7 answers total) 1 user marked this as a favorite
 
ESXi can host Linux guests just fine. It says so right on the ESXi specs page.

Anyway, your questions seems to be sort of answered here:
You can't expand an existing VMFS LUN. You have to make a new RAID set, create a new VMFS datastore or add it as an extent to an existing one. (not recommended)
posted by GuyZero at 4:41 PM on May 11, 2010


Probably. However, RAID is for uptime/convenience, not data protection.

It's probably easier to let the Perc create (and expand as necessary) one big "drive" and then slice and dice it as necessary. I *think* you can even do all the extending and what not online from the OS.

If you really don't want RAID, you are probably better off just hooking the drive cage to the SCSI adapter and ignoring the Perc altogether.
posted by gjc at 4:45 PM on May 11, 2010


Response by poster: ESXi can host Linux guests just fine.

Sorry I should have been more clear, when I said "ESXi doesn't run Linux," I mean that ESXi is its own separate operating system and only runs Linux in the service console (if that is the correct phrasing).

If you really don't want RAID, you are probably better off just hooking the drive cage to the SCSI adapter and ignoring the Perc altogether.

Yeah I really don't have any need for the Perc controller, if it can help fine, but I'm more concerned with the ease in which I can add drives.
posted by geoff. at 4:57 PM on May 11, 2010


If it's an option, I suggest using Citrix Xenserver over Vmware in this case. It's easier to use, and faster too in my experience. You can easily add more storage and then expand an SR (storage repository) after, I have done it many dozens of times. One thing that sucks is that the management console only runs on Windows, but you have full access to every function (and then some) from shell. You can literally set this up and be on your way in about 20 minutes.

Regarding storage, I'd probably do a RAID5 or RAID10. No RAID doesn't sound like a good idea... who wants to recover from backup? That's the way of the sucker. When you are busy with your life and job and you just want to go home and try something neat, having to waste time to fix your stupid server when it breaks is the last thing you want to do. Uptime is king.
posted by tracert at 6:07 PM on May 11, 2010


Best bet is to create the RAID set on the controller and access that as a giant datastore in ESXi. Note that individual guest volumes can't be greater than 256GB. I've been using an OpenSolaris guest with ZFS to expand my filesystems in 250GB increments.
You can leave disks unused and access them directly from the guest OS, but note that you lose snapshot functionality if you do that.
posted by tmt at 8:15 PM on May 11, 2010


You can certainly run Linux guests in ESXi , I do it all the time, but the big issue that jumps out for me is that unless you have a specific need to run more than one VM on this box, the 256GB volume limit might get old fast, so if I were in your shoes I'd just either install CentOS or Openfiler right on the machine and be done with it. If you need multiple VMs you can always install VMWare Server on the machine if you go with a supported Linux distro like CentOS, Fedora, etc.


One other potentially important consideration is that you're mentioning a Perc controller, that usually means it's a Dell server. How old is the server and have you tested the drives you plan to use on it? Last year Dell quietly started shenanigans where their controllers will no longer recognize non-Dell branded hard drives, forcing you to purchase them from Dell directly with all of the associated markup. If your machine has this affliction, adding more drives later might be a more expensive proposition than you originally planned, so your planning may change.
posted by barc0001 at 12:10 AM on May 12, 2010


It's funny, I am running this exact configuration. I have a Dell server with 16GB memory, 2TB storage configured as RAID 5 with a PERC 6/i (a little divergence) onboard. ESXi is running on the server and I have several guests including an Openfiler instance.

The server is optimized to run the ESXi hypervisor which does run off an internal Flash drive so the disks can be dedicated to guest storage.

The 250GB volume size limit has not bothered me so far. If necessary, I would simply add a new volume. My organization is somewhat small, though.

It is an amazing configuration for a colocation type situation, which is what we have. It's really compact, and I can add/remove, startup/shutdown and reconfigure servers on a whim.
posted by rocketpup at 7:07 AM on May 12, 2010


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