Today I received a question which also caught me by surprise, someone updated from vSphere 5.0 and he noticed that when doing an SDRS Maintenance Mode that the setting MaxCostPerEsx41DS did not work. This setting actually limits the number of active SvMotions on a single datastore. You can imagine that this can be desired when you are “limited” in terms of performance. I was a bit surprised as I had not heard that these settings changed at all. Also, a quick search on internal pages and externally did not deliver any results. After a discussion with some support folks and some more digging, I found a reference to a naming change. Not surprising I guess, but as per vSphere 6.0 the setting is called MaxCostPerEsx6xDS. So if you would like to limit the number of SvMotion’s active at the same time, please note the change in names.
For more background on this topic I would like to refer to Frank’s excellent blog on this topic here.
Hi Duncan, first, thanks for all your awsome blogging work!
Since I’m in the process of enabling SDRS to Fully Automated for all of our clusters, I like to temporarily limit concurrent SVMotion operations (to not overload our storage).
I added
config.vpxd.ResourceManager.MaxCostPerEsx6xDS = 31
as advanced setting to vCenter 6.5 and restarted VCSA. If I got the documentation correctly, this should limit concurrent SVMotion to 1 (while also still allowing up to 15 VMotions in addition) looking from the datastore point of view.
Unfortunately, if I take 8 VM’s (all on the same host, 1 virtual disk each) and initiate a SVMotion from one Datastore to another (same Datastore Cluster), there are still two SVMotion running concurrently (Limited to 2 since all VMs are on a single host).
Did I miss something?
Thanks, Cedrick
Looking for an update for vCenter 6.7