After a short break in broadcasts, due to extremely busy times, the Hyper-V Amigos ride again! Yes, fellow Microsoft MVP Carsten Rachfahl (@hypervserver) from Rachfahl IT Solutions and yours truly are back in the saddle!
In episode 15 of the Hyper-V Amigos Showcast we look at VMFleet. VMFleet is a free Microsoft test suite to show/test and help analyze the performance of a Hyper-converged Storage Spaces Direct Setup.
In this episode Hyper V Amigos Showcast 15 – VMFleet explained we show you how to set it up, how it works and how to measure and evaluate your S2D deployment with it. We also share some real life tips with you. All this in just around 2 hours. So stick around for the long haul!
This blog post is a teaser where we show you some of the results we have seen with ReFS v2 in Windows 2016 (TPv4). In a previous blog post (Lightning Fast Fixed VHDX File Creation Speed With ReFS on Windows Server 2016) we have demonstrated the very fast VHDX file creation capabilities we got with ReFS v2. Now we look at another benefit of ReFS v2 in a Hyper-V environment, thanks to a feature or ReFS v2 called block cloning. We get accelerated checkpoint merging with ReFs v2 in Windows 2016
For this short demo we have a virtual machine running Windows Server 2016. It resides on a CSV formatted with REFS (64K unit allocation size). Inside the virtual machine there is a second data disk. Our VM called CheckPointReFS (64K unit allocation size) has this data volume formatted with ReFS (64K unit allocation size) and it runs on the ReFS formatted CSV. The disks in this test are fixed sized VHDX files.
On the data volumes we have about 30GB worth of ISO files. We checkpoint the VMs and then create a copy of those files on the data volume.
We then delete this checkpoint.
Via the events 19070 (start of a background disk merge) and 19080 (completion of a background disk merge) in the Microsoft-Windows-Hyper-V-VMMS/Admin logs we calculate the time this took: 5 seconds.
There are moments you just have to say “WAUW”. Really this rocks and it’s amazing. So amazing I figured I made a mistake and I ran it again … 4 seconds. WOEHOE! What where the times you saw when you last deleted a large checkpoint?
I am really looking forward to do more testing with ReFS v2 capabilities with Hyper-V on Windows 2016.
For those of you who are experimenting with the RoCE variant of RDMA for SMB Direct in Windows Server 2012 (R2), make sure you have a VLAN tag in your configuration if this is more than a simple RDMA over two NICs. The moment you get DBC with PFC & ETS involved you’ll need non default tagged VLANs. Do note that PFC alone is good enough, ETS is strictly speaking not a requirement, but I’d consider doing it if you can.
With Enhanced Transmission Selection (ETS) the network traffic type is classified using the priority value in the VLAN tag of the Ethernet frame. The priority value is the Priority Code Point (PCP), which is described in the IEEE 802.1Q specification and uses a 3-bit field in the VLAN tag with eight possible priority values (0 to 7).
Priority-based Flow Control (PFC) allows to individually pause priorities of tagged traffic and helps to provide lossless or “no drop” behavior for a certain priority at the receiving port. As above, each frame transmitted by a sending port is tagged with a priority value (0 to 7) in the VLAN tag. So for the traffic pause and resume functionality to work we need a VLAN tag to carry the priority value.
Does It Work Without?
But you’ll tell me that, as you may be lacking a DCB capable switch for lab purposes, you used a direct cable between your two RoCE NICs. And guess what RoCE, might have indeed worked for you without a VLAN tag. You can test & get a feel for what RoCE/RDMA can do for you with just the NICs. But as there is no switch involved you’re not using DCB for PFC/ETS and without that the need for the tagged VLAN isn’t there. Also see https://blog.workinghardinit.work/2013/05/03/smb-direct-roce-does-not-work-without-dcbpfc/.
So there you go. Design your RoCE/RDMA network based on DCB with PFC( and ETS) and not just on the tests with an direct cable or you might miss a few details that are quite important. Happy testing!
If you are anything like a lot of people I know and myself you will be very eager to start testing the new features & capabilities of Windows Server 2012 R2 that is now available for testing purposes in preview. Now Microsoft has launched their IT Pro Summer Grand Prix campaign that might get you something extra next to the knowledge you will gain.