Modify a vSAN ReadyNode

VMware recommends using vSAN ReadyNodes when running vSAN in production. Doing so simplifies the life of the administrator, who doesn't have to ensure all components in the server are certified, have the right firmware, etc. VMware provides the following link where users can find the different vSAN ready node options…

vSAN Availability during Maintenances

When performing vSphere maintenances while using vSAN, VMware recommends to almost always use the 'Ensure Accessibility' option. This option ensures that all vSAN objects are consistent, minimizes the migrated data, and the time it takes the host to enter maintenance mode. The drawback is that vSAN objects with FTT=1…

vSAN Remaining Capacity

The fundamentally different architecture of vSAN compared to traditional SAN storage brings some operational challenges. One of these is what happens when capacity is running low, and what value to set the alert threshold to ensure workloads don’t experience problems. One problem is that there are significant differences between…

vSAN Operations: Local Disk Identification

If a local disk on a server fails (or is about to fail) the storage controller will notice this and will inform the vCenter via CIM. The failed disk should then be indicated both in the vCenter and on the disk LED. The disk identification will in these circumstances be…

vSAN Operations: Disk Failure Impact

Using vSAN as vSphere storage has many advantages, it's cheap, performs well and it's easy to configure. What hasn't been widely discussed are the operational impacts of running vSAN (or any HCI for that matter). This is especially relevant for large organisations, with separate storage, virtualization and datacenter server teams.…

vSAN Host Capacity Design

Designing a vSAN cluster from scratch poses a lot of challenges. One of the challenges I encountered is to ensure that resources (memory, CPU and storage) in the cluster gets utilized evenly, and that you for instance don't run out of memory while having plenty of remaining storage capacity. I…

vSAN VM Write Latency Bug

Having recently had the opportunity to do a bit of performance analysis of a hybrid vSAN cluster, I recently found a bug, causing high VM write latency and reduced read cache hit rate. Configuration The vSAN environment analysed is a 6 host cluster running ESXi 6.0U2 (vSAN 6.2)…