harbar.net component based software & platform hygiene

SharePoint 2016 Nugget #2: Distributed Cache Size in MinRole Farms

Print | posted on Friday, April 15, 2016 7:07 PM

In SharePoint 2013, the Distributed Cache size is set to half of ten percent of the total RAM on the server. This means that on a server with 8Gb RAM, the Cache Size (the allocation for data storage) is 410Mb. Another 410Mb is used for the overhead of running the Cache.

This is a reasonable default as the system has no way of knowing which other services will be provisioned onto the server. And of course by default in SharePoint 2013 every machine in the farm will host Distributed Cache, unless you build your farm properly using the –SkipRegisterAsDistributedCacheHost switch.

The problem is that for anything other than a dev/test/hacknslash/demo box this is a silly number, and nowhere near enough for the Distributed Cache to actually be of any use in terms of social data.

With SharePoint 2016 if you continue to build the farm using the old approach – i.e. using a role of Custom and/or 
–ServerRoleOptional this behaviour is retained and the default cache size will be half of ten percent of total RAM:


However if instead you build your farm using MinRole and add servers of role DistributedCache to the farm, we now provision a much more reasonable and useful default:


The size is now half of 80 percent of the total RAM, so on a box with 8Gb this will be 3276Mb. That’s much more like it.

This is because we know that this server and any others of the same role will only ever host Distributed Cache and the Web Application Service. Optionally it could also host Request Management and the Claims to Windows Token Service. Neither of those services will ever consume a significant amount of RAM. Whilst they shouldn’t be there (more on that in a future post), the impact is negligible.

Yet another reason why MinRole isn’t the bag of nails it seems so popular for community “celebrities” to wax about.  Another reason why a MinRole farm will batter a SharePoint 2013 in terms of performance and throughput out of the gate – much more appropriate defaults for critical system configuration that so many customers have ignored with SharePoint 2013.

The devil is in the details. MinRole… kinda tasty. I think I’ll scoff me one right now…