Introduction

Wow. That’s what I have to say. WOW! I configured a two node virtual machines

cluster running Windows 8 Server Developer Preview to test the SMB2 Scale Out functionality and I smiling. In my previous blog Transparent Failover & Node Fault Tolerance With SMB 2.2 Tested I already tested the transparent failover with a more traditional active-passive file cluster and that was pretty neat. But there are two things to note:

The most important one to me is that the experience with transparent failover isn’t as fluid for the end user as it should be in my opinion. That freeze is a bit to long to be comfortable. Whether that will change remains to be seen. It’s early days yet.
The entire active-passive concept doesn’t scale very well to put it mildly. Whether this is important to you depends on your needs. Today one beefy well, configured server can server up a massive amount of data to a large number of users. So in a lot of environments this might not be an issue at all (it’s OK not to be running a 300.000 user global file server infrastructure, really ).

So bring in “File Server For Scale-Out Application Data” which is an active/active cluster. This is intended for use by applications like SQL server & Hyper.-V for example. It’s high speed and low drag high available file sharing based on SMB 2.2, Clusters Shared Volumes and failover clustering. The thing is, at this moment, it is not aimed at end user file sharing (hence it’s name ““File Server For Scale-Out Application Data”. When I heard that, I was a going “come on Microsoft, get this thing going for end user data as well”. Now that I have tested this in the lab, I want this only more. Because the experience is much more fluid. So I have to ask Microsoft to please get this setup supported in a production environment for all file sharing purposes! This is so awesome as an experience for both applications AND end users. The other approach that would work (except perhaps for scaling) is making the transparent failover for an active-passive file cluster more fluid. But again, early days yet.

Setting Up The Lab

Build a “File Server for scale-out application data” cluster

You need three virtual machines running Windows 8, two to build the cluster and one to use as a client.Once you have the cluster you configure storage to be used as a Clustered Shared Volume (CSV)

You’ll see the progress bar adding the storage to CSV

And voila you have CSV storage configured. Note that you don’t have to enable it any more and that there are no more warnings that this is only supported for Hyper-V data.

Now navigate to Role, right click and select “Configure Roles”

This brings up the High Availability Wizard

Click Next and select “File Server for scale-out application data”

Give the Client Access Point a name

Click Next and on the following wizard page click confirm

And voila you’re done. Do notice the wizards skips the “Configure High Availability” step here.

Get a share up and running for use

Don’t make the mistake of trying to double click on the you see in the Role. Go to the node who’s the owner of the role and navigate to the role “ScaleOut”, right click and select add shared folder.

Select the cluster shared volume on the server “ScalingOut” which is actually the client access point.

I gave the share the name SOFS (Scale Out File Share)

I like Access Based Enumerations so I enable this next to Enable continuous availability that is enabled by default.

Than you get to the permissions settings. Here you have to make sue you set the share permissions to more than read if you want to do some writing to the share. Nothing new here Winking smile

After that you’re almost done. Confirm your settings & click Commit

Watch the wizard do it’s magic

And it’s all setup

Play Time

We have a third node “Independence” running Windows 8 Server to use as a client. As you can see we can easily navigate to the “server” via the access point.

And yes that’s about all you have to do. You can see the ease of name space management at work here.

Now let’s copy some data and turn of a one of the cluster nodes, the one that owns the role for example …

I was copying the content of the Windows 8 Server folder from Independence and failed over the node, the client did not notice anything. I turned off the node holding the role and still the client did only notice as short delay (a couple of seconds max). This was a complete transparent experience. I cannot stress enough how much I want this technology for my business customers. You can patch, repair, replace, file server nodes at will at any given moment en no application or user has to notice a thing. People, this is Walhalla. This is is the place where brave file server administrators that have served their customers well over the years against all odds have the right to go. They’ve earned this! Get this technology in their hands and yes even for end user file data. Or at least make the transparent failover for user file sharing as fluid. Make it happen Microsoft! And while I’m asking, will there ever be a SMB 2.2 installable client for Windows 7? In SP2, please?!

Learn more here by watching the sessions from the Build conference at http://www.buildwindows.com/Sessions

Noticed bugs

The shares don’t always show up in the share pane, after failover.

Conclusion

This is awesome, this is big, this is a game changer in the file serving business. Listen, file services are not dead, far from it. It wasn’t very sexy and we didn’t get the holey grail of high availability for that role as of yet until now. I have seen the future and it looks great. Set up a lab people and play at will. Take down servers in any way imaginable and see your file activities survive without at hint of disruption. As long a you make sure that you have multiple nodes in the cluster and that if these are virtual machines they always reside on different nodes in a failover cluster it will take a total failure of the entire cluster to bring you file services down. So how do you like them apples?

Transparent Failover and node fault tolerance with SMB 2.2 in Windows 8 Server is something that caught my attention immediately. The entire effort in infrastructure has been to keep the plumbing as invisible & unnoticed as possible. In some areas we had great success in others not so much. Planned & unplanned down time of file servers has always been an issue as there was always a short or longer outage and any failover meant disconnecting & reconnecting leading to all kinds of end users problems and confusion. To them the network is down. But the same issues exist on the server side with apps depending on files shares or servers like SQL Server that are writing backups to remote share or read data from such a share. Often it needs some kind of human intervention to correct the situation. No not even 3rd party clustered file systems and active-active clustering software could achieve this. The SMB protocol prior to 2.2 did not allow for it.

So when one hears it is a possibility now we want to test this! So we throw some virtual machines on the test cluster and build a file cluster with windows 8 server and we also have a 3rd server to act as a client with SMB 2.2. Open the Failover Cluster Manager right click roles and choose to configure a role.

You’ll see the familiar wizard, click next

And choose the file server role

Give the Client Access Point a name and add an IP address.

Add some storage

And voila … after the confirmation we’re asked to configure high availability

This opens the New Share Wizard

…this is all pretty straight forward so I’ll leave out the screenshots but for the most important one where we explicitly uncheck the “Enable continuous availability” as we want to first run a test without it Smile

Continue through the wizard & voila you have a clustered file server with a Client Access Point as a single namespace. Please not that you can connect to this using that single name space. No need for \serverABizzShare & \ServerBBizzShare and going fancy with redundant DFS name spaces and the like.

Remember we still need to make this share highly available but let’s do some file copies and fail over the node to see what this looks like without transparent failover. Select the role transparent, right click, choose “Move” and “Select Node”.

Choose an available node and click OK

As you can see this looks rather familiar.

Let’s make that share continuously available. Go to and double click on the share you want to configure.

You’ll see a progress dialog whilst information is retrieved …

… and then the share properties are presented, most is familiar stuff but we need the bottom one “Settings”. Select the check box to make the share continuously available.

Now let’s try that file copy of again whilst failing over the file server role to another node.

So there is no loss of data, no need to the client to reconnect, you don’t have to retry but you do have a freeze that lasts for about 20 seconds on my test lab. I hope this will still improve before RTM.

What we learned here is that we can have Transparent (File Share) failover with SMB 2.2 in a virtualized environment and we can give it a “Client Access Point” name like “MyOldFileServer” so that users are not confused or need to learn another UNC path. There are many options to achieve keeping old namespaces around for end user ease of use but this is an extra ace up our sleeve. For now planned (patching, server maintenance) or unplanned (crash) is a 20 second freeze experience right now as the file share fails over. This freeze is probably due to active–passive clustering. For now active-active is not recommended/supported for file sharing in an end user scenario. I think they are “worried” of huge file shares with a zillion meta data updates to sync. But this is supported for apps like hyper-V, SQL Server backups or apps needing file data etc. I’m going to try it next and for user data. Things might change before RTM and with multichannel, RDAM, 10Gbps, NIC teaming in the OS perhaps that active-active scenario might be feasible for user file data? PLEASE? Otherwise here’s another request for “Windows 8 Server R2” Winking smile

The secret sauce is in:

SMB 2.2 on both client & server
Resume Key
SMB 2.2 Witness service which is stet to running when you make an share continuous available.

Go watch the sessions from the Build conference to hear more on al this. The work they’ve put in to this + some of the complexities are quite amazing. http://www.buildwindows.com/Sessions

Things to find out: how to rename a Client Access Point or how to delete it. Adding a new one is easy.

Warning: It’s September 23rd 2011 and the Developer Preview is a little rough around the edges don’t run this on anything you need to get your bills paid yet

Working Hard In IT

My view on IT from the trenches

Tag Archives: SMB 2.2

Transparent Failover & Node Fault Tolerance With SMB 2.2 Tested