I posted about HA/DRS settings for VSAN Stretched Clustering yesterday and posted an intro to 6.1 and all new functionality which includes stretched clustering. As part of our VMworld session Rawlinson Rivera recorded a nice demo. We figured we should share it with the world, so I added the voice-over so at least it is clear what you are looking at and why certain things are configured in a specific way. I hope this demo shows how dead simple it is to configure VSAN stretched clustering, and how it handles a full site failure. Enjoy,
vSAN
HA/DRS configuration with Virtual SAN Stretched Cluster environment
This question is going to come sooner or later, how do I configure HA/DRS when I am running a Virtual SAN Stretched cluster configuration. I described some of the basics of Virtual SAN stretched clustering in a what’s new for 6.1 post already, if you haven’t read it then I urge you to do so first. There are a couple of key things to know, first of all the latency between data sites that can be tolerated is 5ms and to the witness location ~100ms.
If you look at the picture you below you can imagine that when a VM sits in Fault Domain A and is reading from Fault Domain B that it could incur a latency of 5ms for each read IO. From a performance perspective we would like to avoid this 5ms latency, so for stretched clusters we introduce the concept of read locality. We don’t have this in a non-stretched environment, as there the latency is microseconds and not miliseconds. Now this “read locality” is something we need to take in to consideration when we configure HA and DRS.
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VMworld Virtual SAN slidedecks up on slideshare
I just posted the slidedecks that I presented at VMworld on Virtual SAN up on slideshare. The recording and the slides will probably at some point also show up on vmware.com but as I had many requests from people to share the material I figured I would do that straight after the event. If you have any questions don’t hesitate to ask.
NexentaConnect for VSAN for free? Get it now!
I was at VMworld last week and bumped in to the Nexenta team. They told me about this great promotion they are running (limited time!) for NexentaConnect. NexentaConnect provides you NFS storage on top of VSAN, Cormac wrote an article about it a while back which I suggest reading. The promotion gives you NexentaConnect for $ 0,- and that includes:
- NexentaConnect for VMware Virtual SAN license (s)
- Unlimited raw storage capacity to match VMware VSAN Licenses
- Nexenta technical support for first 12 months included
Now I have seen many companies giving away software for free, but can’t recall having seen anyone include free support for 12 months. If you are a Virtual SAN user, or about to deploy/implement Virtual SAN, and looking to include some form of file services on top of it, then NexentaConnect may just be what you are looking for. I definitely recommend giving it a try, it is free and comes with support… what more can you ask for?
Have fun!
VMworld Session: VSAN – Software Defined Storage Platform of the Future #STO6050
Unfortunately I haven’t been able to attend too many sessions, only 2 so far. This is one I didn’t want to miss as it was all about what VMware is working on for VSAN and layers that could sit on top of VSAN. Rawlinson and Christos spoke about where VSAN is today first. Mainly discussion the use cases (monolithic apps like Exchange, SQL etc.) and the simplicity VSAN brings. After which an explanation of the VSAN object/component model was provided which was the lead in to the future.
We are in the middle of an evolution towards cloud native applications Christos said. Cloud native apps scale in a different way then traditional apps, and their requirements differ. Usually not a need for HA and DRS, and will contain this functionality within their own framework. What does this result in for the vSphere layer?
VMware vSphere Integrated Containers and VMware Photon Platform enabled these new types of applications. But how do we enable these from a storage point of view? What kind of scale will we require? Will we need different data services? Will we need to different tools, what about performance?
First project being discussed is the Performance Service which will come as part of the Health Check plugin. Providing cluster level, host level, disk group level, disk level… The Performance Service Architecture is very interesting and is not a “standard vCenter Server service”. Providing deep insights using per host traces is not possible as it would not scale. A distributed model is proposed which will enable this, but in a decentralized way. Each host can collect data, each cluster can roll this up, and this can be done for many clusters. Data is both processed and stored in a distributed fashion. The cost for a solution like this should be around 10% of 1 core on a server. Just think what a vCenter Server would look like if you had the same type of scale and cost, with a 1000 host solution could easily result in a 100 vCPU requirement, which is not realistic.
Rawlinson demoes a potential solution for this, in this scenario we are talking 1000s of hosts of which data is gathered, analyzed and presented in what appears to be an HTML-5 interface. The solution doesn’t just provides details on the environment it also allows you to mitigate these problems. Note that this is a prototype of an interface that may or may not at some point in time be released. If you like what you see though, make sure to leave a comment as I am sure that helps making this prototype reality!
Next being discussed is the potential to leverage VSAN not just for virtual machines, but also for containers, having the capabilities to store files on top of VSAN. A distributed file system for cloud native apps is now introduced. Some of the requirements for a distributed file system would be a scalable data path, clones at massive scale, multi-tenancy and multi-purpose.
VMware is also prototyping a distributed file system and have it running in their labs. It sits on top of VSAN and leverages that scalable path and uses it to store its data and metadata. Rawlinson demonstrates how he can create 2000 clones of a file in under a second across a 1000 host and runs his application. Note that this application isn’t copied to those 1000 hosts, but it is a simple mountpoint on 1000 hosts, truly distributed filesystem with extremely scalable clone and snapshot technology.
Christos wraps up, key points are that VSAN will be the enabler of future storage solutions as it provides extreme scale, with at a low resource overhead. Awesome session, great peak in to the future.