A while ago I had the pleasure to join David S. Linthicum from GigaOm on their Voices in Cloud Podcast. It is a 22 minute podcast where we discuss various VMware efforts in the cloud space, edge computing and of course HCI. You can find the episode here, where they also have the full transcript for those who prefer to read instead of listen to a guy with a Dutch accent. It was a fun experience for sure, I always enjoy joining podcast’s and talking tech… So if you run a podcast and are looking for a guest, don’t hesitate to reach out!
A question just came in, and I figured other people may have the same question so I would share it. The question was if a vSAN IO limit would impact resync traffic or for instance SvMotion? In this case the customer defines limits within each policy to ensure VMs do not interfere with other VMs or excessively uses IO resources. Especially in cloud environments this can be useful, or when running production and test/dev on the same cluster. The concern, of course, was if this limit would impact for instance recovery times after a failure. Because you can imagine that a limit of 50 IOPS would be devastating when a VM (or multiple VMs) need to have objects resynced.
The answer is simple: no, the IO limit specified within a policy does not impact resync traffic (or SvMotion for that matter). It only applies to Guest IO to a VMDK, namespace or swap object. Which means that it is safe to set limits when it comes to recovery times.