Committed memory in Linux is less than expected [closed]
Half of this host's memory is in anon private pages. Most of that is the process you identified. Committed_AS
relatively low at 14% of MemTotal
implies not much is in use yet for actual data.
Operating systems are lazy. Linux will not touch all 14 GB this program asked for. Instead, as this x86 CPU supports 2 MB and 1 GB pages, Linux assigns several of those to this process and pretends they are entirely zeroed. Notice DirectMap
showing many hardware pages of 1 GB. HugePages can be configured explicitly by the administrator, but that meminfo shows zero of those configured.
Just this allocation takes very little physical memory, so Committed_AS
starts low. If and when the application fills these with real data, it will increase.
Regarding capacity planning, right now this host currently has plenty of memory. Anon and shared memory is limited to half, 36% cached for fast file access, and a few GB free and unused to satisfy immediate memory allocation demands. And of course Committed_AS
far under MemTotal
Even though the application's memory allocations fit the size of the host, find out why it was sized that way. If this is an in memory database sized for future growth, that might make sense. Or maybe 32 GB is your medium sized VM / small sized physical server, over sizing may be easier operationally.