Host memory usage is excessively high

Cause

The buffer/cache value is too large and has not been released.

Solution

1. Run the sync command to force-write data in the buffer to disk.

2. Run the following commands in sequence on the host to release cache space:

   [root@localhost ~]# echo 1 > /proc/sys/vm/drop_caches;
   [root@localhost ~]# echo 2 > /proc/sys/vm/drop_caches;
   [root@localhost ~]# echo 3 > /proc/sys/vm/drop_caches