I run OpenBSD/amd64 5.2 on a system with 12GB of RAM, and I want to use about 6GB to 8GB for filesystem caching.
By default, 5.2 amd64 comes with
sysctl kern.bufcachepercent set to
20 (20%); I've increased it to 50% and then to 60%, and then went through lots of files that definitely total above 10GB, yet, when I go into
top, I am shown the following line:
Memory: Real: 25M/1978M act/tot Free: 9961M Cache: 1670M Swap: 0K/48G
That's 1.7GB out of 12GB, less than 15%! I've even tried increasing
kern.maxvnodes from 117091 to 400000 (and
kern.numvnodes did indicate that all 400k of vnodes got utilised pretty quickly), but I'm still having under 2GB of RAM used for caching.
Is it not possible to use 6GB of RAM for disc cache on OpenBSD 5.2 amd64? Is it limited to something around 1.7GB?