Which policy changes can trigger a rebuild on vSAN?

Some time ago, I wrote about which policy changes can trigger a rebuild of an object. This came up again recently, as it was something that Duncan and I covered in our VMworld 2017 session on top 10 vSAN considerations. In the original post (which is over 3 years old now), I highlighted items like increasing the stripe width, growing the read cache reservation (relevant only to hybrid vSAN) and changing FTT when the read cache reservation is non-zero (again only relevant to hybrid vSAN) which led to a rebuild of the object (or components within the object). The other…

A closer look at Portworx

Last month I had the opportunity to attend DockerCon17. One of the break-out sessions that I attended was from a company called Portworx. Portworx provide a solution for stateful docker container storage, which is what caught my interest. There are lots of companies who have already created docker volume plugins for their existing storage solutions, including VMware. However Portworx seem to be approaching this a bit differently, and are providing a layer of abstraction from the underlying host storage. So you might be using cloud (e.g. EBS from AWS), or SAN or NAS or indeed you might only have local…

A closer look at Cohesity 4.0

Last week, I had a chance to catch up with my pal, Rawlinson Rivera. Rawlinson and I worked closely on a lot of storage related stuff at VMware, but he has since moved on to pastures new, and is currently the CTO for the Global Field over at Cohesity. I’ve written about Cohesity a number of times on this blog. I think the first time I wrote about them was during VMworld 2015, just before the 1.0 product launched, and they were still pitching the idea of secondary storage and how they would take care of things like snaps, clones,…

Erasure Coding and Quorum on vSAN

I was looking at the layout of RAID-5 object configuration the other day, and while these objects were deployed on vSAN with 4 components, something caught my eye. It wasn’t the fact that there were 4 components, which is what one would expect since we implement RAID-5 as a 3+1, i.e. 3 data segments and 1 parity segment. No, what caught my eye was that one of the components had a different vote count. Now, RAID-5 and RAID-6 erasure coding configurations are not the same as RAID-1. With RAID-1, we deploy multiple copies of the data depending on how many…

A closer look at Rubrik Cloud Data Management v3.1

When I started to write this post, I looked back over my notes from previous conversations with the team at Rubrik and realized that my first conversation with them was almost 2 years ago. How time flies! I still remember meeting Rubrik at one of our VMware Partner Exchanges (PEX) in 2015, and getting a demo from Bipul Sinha (Rubrik CEO) and Julia Lee (Product Marketing). I also remember when Chris Wahl moved to Rubrik (almost 18 months ago now), thinking what a great move that was for both Chris and Rubrik. Well, when I caught up with Chris last…

VSAN 6.2 Upgrade – Failed to realign objects

A number of customers have reported experiencing difficulty when attempting to upgrade the on-disk format on VSAN 6.2. The upgrade to vSphere 6.0u2 goes absolutely fine; it is only when they try to upgrade the on-disk format, to use new features such as Software Checksum, and Deduplication and Compression, that they encounter this error. Here is a sample screenshot of the sort of error that is thrown by VSAN: One thing I do wish to call out – administrators must use the VSAN UI to upgrade the on-disk format. Do not simply evacuate a disk group, remove it and recreate…

Cohesity Data Platform 2.0 is out

Cohesity have released their next version (2.0) of the Cohesity Data Platform. I met Cohesity at VMworld 2015, and  I wrote about my first impressions of the solution in a blog post from back in August 2015. In a nutshell, Cohesity are positioning their Data Platform as hyper-converged secondary storage. They want to stop the silo’ing of different storage for backups, file shares and analytics in the data center, and offer you a single platform for all of your secondary storage needs. Now they are ready with the next version, so lets take a quick look at what is coming…