Easy VSAN question. Adding a new host to VSAN, impact to the VSAN cluster?

[cyberfed2727]

Hey guys,

Simple question. We have an existing ESXi 5.5 cluster that has six ESXi hosts configured in VSAN. Each of the six ESXi hosts are contributing 1 SSD drive (Fusion I/O card) and 1 spinning local hard disk.  We want to add a 7th server but it only has a Fusion I/O SSD card and no spinning local disks (ESXi is on an internal SD card). So this 7th host only has 1 SSD disk to contribute to the VSAN.

Are there any issues with this? I figured not because you can add a host that contributes no storage so I'm assuming just contributing one SSD disk would be fine. Yes?

Lastly when we add the 7th host and tell VSAN to incorporate the SSD disk its not going to mess with the existing VSAN or any guests on it right? I mean it'll just take the new drive and add it to the VSAN with no downtime or surprises right? I'm pretty sure I know the answer to all these but management is cautious and we have no test lab for VSAN so we wanna play it safe.

Much appreciated.

[elerium]

VSAN disk groups requires minimum 1 SSD and 1 capacity device (magnetic in your case). If you added a 7th host with only the Fusion I/O card, the storage from this 7th node would not be added to VSAN. You could still create a regular VMFS datastore with it, but it would not be VSAN storage.

Adding new hosts and new VSAN disk groups shouldn't mess with anything existing unless you have some really bad misconfiguration (duplicate IPs or network improperly setup), much of it can be avoided by bringing the new host into the cluster under maintenance mode and making sure health check passes before taking it out of maintenance mode.