Those of you familiar with VSAN will be aware that when it comes to virtual machine deployments, historically, objects on the VSAN datastore were deployed either as a RAID-0 (stripe) or a RAID-1 (mirror) or a combination of both. From a capacity perspective, this was quite an overhead. For instance, if I wanted my VM to tolerate 1 failure, I need two copies of the data. If I wanted my VM to tolerate 2 failures, I needed three copies of the data and if I wanted my VM to tolerate the maximum number of failures, which is 3, then I…
Now that VSAN 6.2 is officially launched, it is time to start discussing some of the new features that we have introduced into our latest version of Virtual SAN. Possibly one of the most eagerly anticipated feature is the introduction of deduplication and compression, two space efficiency techniques that will reduce the overall storage consumption of the applications running in virtual machines on Virtual SAN. Of course, this also lowers the economics of running an all-flash VSAN, and opens up all-flash VSAN to multiple use cases.
If you were wondering why my blogging has dropped off in recent months, wonder no more. I’ve been fully immersed in the next release of VSAN. Today VMware has just announced the launch of VSAN 6.2, the next version of VMware’s Virtual SAN product. It is almost 2.5 years since we launched the VSAN beta at VMworld 2013, and almost 2 years to the day since we officially GA’ed our first release of VSAN way back in March 2014. A lot has happened since then, with 3 distinct releases in that 2 year period (6.0, 6.1 and now 6.2). For…
This week Datrium announced that their DVX system is now generally available. I met these guys at VMworld 2015, and wrote a closer look at Datrium here. If you want a deeper dive into their solution, please read that post. But in a nutshell, their solution uses a combination of host side flash devices to accelerate read I/O, while at the same time writing to the Datrium hardware storage appliance (called a NetShelf). The NetShelf provides “cheap, durable storage that is easy to manage”. The DVX architecture presents the combined local cache/flash devices and NetShelf as a single shared NFS…
We are hearing about a number of VSAN stretched cluster implementations going on at the moment, which is great news. I just set up such a configuration once again in my lab as we look at some various scenarios for the next release of VSAN. Now, for anyone looking at implementing VSAN stretched cluster, there is the VSAN 6.1 stretched cluster guide which should be your first port of call. However I noticed that once VSAN stretched cluster is implemented, you get a few warnings that you typically wouldn’t see in standard VSAN deployments. That is what I want to…
This is something I only learnt about very recently, and something I was unaware of. It seems that we have made a major improvement to the way we do snapshot consolidation in vSphere 6.0. Many of you will be aware of the fact that when they VM is very busy, snapshot consolidation may need to go through multiple iterations before we can successfully complete the consolidation/roll-up operation. In fact, there are situations where the snapshot consolidation operation could even fail if there is too much I/O. What we did previously is used a helper snapshot, and redirected all the new…
In the VSAN Troubleshooting Reference Manual, the following description of VSAN.ClomMaxComponentSizeGB is provided: By default VSAN.ClomMaxComponentSizeGB is set to 255GB. When Virtual SAN stores virtual machine objects, it creates components whose default size does not exceed 255 GB. If you use physical disks that are smaller than 255GB, then you might see errors similar to the following when you try to deploy a virtual machine: There is no more space for virtual disk XX. You might be able to continue this session by freeing disk space on the relevant volume and clicking retry.