Maximum map count check

Continuing from the previous point, to use mmap effectively, Elasticsearch also requires the ability to create many memory-mapped areas. The maximum map count check checks that the kernel allows a process to have at least 262,144 memory-mapped areas and is enforced on Linux only. To pass the maximum map count check, you must configure vm.max_map_count via sysctl to be at least 262144.

Alternatively, the maximum map count check is only needed if you are using mmapfs as the store type for your indices. If you do not allow the use of mmapfs then this bootstrap check will not be enforced.