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…
If you’ve been following my series on VSAN 6.2 blog posts, you’ll be aware of a considerable number of new features, especially around space efficiency, such as deduplication and compression. On top of this, there is a new on-disk format (v3) and a new software checksum mechanism. All of these features introduce some capacity overhead in their own right, so as to allow administrators track where the storage consumption is occurring a brand new capacity view has been introduced with VSAN 6.2.
There is a new snapshot format introduced in VSAN 6.0 called vsanSparse. These replace the traditional vmfsSparse format (redo logs). The vmfsSparse format was used when snapshots of VMs were taken in VSAN 5.5, and are also the format used when a snapshot is taken of a VM residing on traditional VMFS and NFS. The older vmfsSparse format left a lot to be desired when it came to performance and scalability. This KB article from our support team, indicating that no snapshot should be used for more than 72 hours, and snapshot chains should contain no more than 2-3 snapshots,…
I was heavily involved in the documentation effort for VSAN 6.0, but I know that not everyone likes to RTFM, so to speak. What I thought I would do in this post is give an overview of the upgrade process, and highlight some considerations. But I really would urge you to read through the VSAN 6.0 Administrators Guide, and perhaps the VSAN Troubleshooting Reference Manual, especially the sections dealing with upgrades, if you do plan to upgrade from VSAN 5.5 to 6.0. There is a lot of useful information there. There are four steps to the upgrade process: Upgrading vCenter…