Does anyone know if there is a service out there that can be used as a file share witness for a Windows Server 2008 R2 Failover Cluster File share witness?

I have a two-node cluster but no good place for my file share witness - can I use the cloud?

Edit: I feel I should add some qualification to this question as it seems to have struck a nerve as several people think it is a very bad idea. Whether or not this is a good idea was not really the question as I did not provide sufficient detail of the environment for you to make such a judgement. For the benefit of others who may come across this thread, this is quite definitely not a good idea for most classic cluster installations. In the case of geographically dispersed clusters or clusters that otherwise depend on the internet in any event, this could be a compelling option if it is otherwise difficult to find a suitable location for your FSW.

As far as the general importance of the FSW goes, and what would happen if you lose connectivity to it, the answer is "not much" - as a critical component of your cluster goes, it is probably the least critical. In order for there to be any impact at all other than a few errors, at least one more component of your cluster would have to fail. I was actually innaccurate in a comment below - in this state you can failover - just not automatically. Don't get me wrong - you are definitely in a degraded state, and you don't want to be here for long or very often, but depending on your definition of "very bad things" - this would not qualify in my opinion.

The bottom line is that this might be a good idea in very specific circumstances. I marked JohnThePro's answer although I have not been able to verify whether it will work.

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    This is a terrible idea. Don't even attempt to do it. – Holocryptic Feb 17 '12 at 18:15
  • I appreciate the words of warning - would your reservations be based on a general dislike/mistrust of cloud stuff or is there a technical/architectural reason why it's a bad idea? – Mike DeFehr Feb 17 '12 at 21:12
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    Both. What happens when you lose your internet connection? What happens when your internet connection bounces? What happens when your building loses power? Very Bad Things is the answer to all three. You don't put a critical component of your cluster outside of your immediate control. – Holocryptic Feb 17 '12 at 21:17
  • Ah - good points all - in this case, the servers are in a hosted environment and the application is a public website - if the internet connection goes down, bad things have already happened. I agree that, for an on-prem installation, this would be questionable. – Mike DeFehr Feb 17 '12 at 21:39
  • Ok, but based on your comment to John you'd still have to put the witness in a location separate from where your servers are. It adds a layer of complexity that you probably don't want to have. – Holocryptic Feb 17 '12 at 21:53

If you can, I'd recommend utilizing FreeNAS for this. If you can find MINIMAL resources anywhere on your network and setup a virtualized instance of this, you'll be able to meet the requirements of the quorum disk for your cluster.


and a walkthrough for provisioning the target in FreeNAS and finding it in your cluster.


  • A good idea, but the issue is that these are rented servers in a commercial data center. We don't have the luxury of adding a simple device for a FSW - we'd have to rent a whole third server, which is cost-prohibitive. – Mike DeFehr Feb 17 '12 at 21:45
  • You could use these guys. gigenet.com/hosting-solutions/storage/iscsi-san.html – JohnThePro Feb 17 '12 at 21:51
  • Not sure I follow - is this service an iSCSI SAN volume accessible over the internet? Very cool, but all I should need is an SMB share... – Mike DeFehr Feb 17 '12 at 22:07
  • That is what they are. These guys offer 1GB free, and using WebDAV you can create a 'mapped drive' from their online storage. Should meet your needs. drivehq.com/help/features/webdav.aspx – JohnThePro Feb 17 '12 at 22:18
  • OK - I am familiar with similar services - can this actually be configured as a FSW, though? Any idea if Microsoft would support it if you could? – Mike DeFehr Feb 17 '12 at 22:56

I'm gonna make this an official answer.

This is a terrible idea. Don't even attempt to do it. I don't care that some guy thought that it might be a great idea what with all the new fangled cloud technology out there.

What happens when you lose your internet connection? What happens when your internet connection bounces? What happens when your building loses power? Very Bad Things is the answer to all three. You don't put a critical component of your cluster outside of your immediate control.

Can you do it? Yes, with the right amount of backup connections and distributed computing and all that you can very well do this.

Is it a good idea? Very simply, IMO, --- NO

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    +1 -- Yes you CAN do it. You can also use a USB hard drive as the witness if you really want to, but rip that drive out unexpectedly and see what happens. Now make that drive as reliable as the average internet uplink :) – voretaq7 Feb 17 '12 at 22:01
  • You know I'm talking about the File Share Witness for quorum majority only, right? Not the cluster storage itself - if you lose your FSW, the cluster service just complains a bit until it's back (of course you can't failover...) – Mike DeFehr Feb 17 '12 at 22:06
  • Yes, but if you lose your connection to the FSW in a real situation you're going to want to failover and won't be able to. Then its all moot. – Holocryptic Feb 17 '12 at 22:12
  • It's just my $.02. Like I said it can be done. But that doesn't necessarily mean it should be done. – Holocryptic Feb 17 '12 at 22:13

Interesting! At least one clustering blogger liked the idea:

Identifying a 3rd geographic location can be challenging for some companies, but with the advent of cloud based utility computing like Amazon EC2 and GoGrid, it is well within the reach of all companies to put a file share witness in the clouds and have the resiliency required for effective multi-site clusters. In fact, you may consider the cloud itself as your secondary data center and just failover to the cloud in the event of a disaster. I think the possibilities of cloud based computing and disaster recovery configurations are extremely enticing and in fact I plan on doing a whole blog post on a just that in the near future.

Microsoft says

The external share is used to store only a small amount of data. Therefore, a share that has between 2 megabytes (MB) and 5 MB of available hard disk space is sufficient.

My impression is that any Windows hosting service offering reliable access to an SMB share on a server that belongs to your cluster's domain and forest could work. You may wish to connect via VPN.

Thanks to Tony Roth for the blog reference.

  • Thanks - I'm familiar with David Bermingham, and his post is probably where I got the idea. It certainly seems compelling - I guess if no one is doing it, though, then there's no definitive answer to my question... – Mike DeFehr Feb 17 '12 at 21:10
  • If you call/email/twitter Dave at Steeleye/SIOS, might he have your definitive answer? And know a good Windows VPS provider? He's on LinkedIn. If the OS is W2003 or newer, it's hard to imagine why any $50/mo VPS host w/decent track record wouldn't make you happy...or is that too pricey? Locking a smallish file shouldn't be THAT hard. – Paul Feb 17 '12 at 23:31
  • That blog reference is for multi-site (2 or more sites) clusters. You definitely don't want to add an external FSW for a single-site cluster. Just ask your provider/colo for a small SMB/CIFS share at the same facility. – Eric Nicholson Mar 14 '12 at 19:05

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