Clean cache under Linux to free up memory

 Free Total        used       free     shared    buffers     cachedmem:         1920472    1845892      74580              462708     338068-/+ buffers/cache:    1045116     875356Swap:            0           0          0

[Email protected] ~]#Sync[[Email protected]~]#Echo 1>/proc/sys/vm/Drop_caches[[email protected]~]#Echo 2>/proc/sys/vm/Drop_caches[[email protected]~]#Echo 3>/proc/sys/vm/Drop_caches[[email protected]~]# FreeTotal used Freeshared buffers Cachedmem:1920472    1015300     905172        184        992      46960-/+ Buffers/cache:967348     953124Swap:0          0          0[[Email protected]~]#

For a few days I didn't find out which application was using the memory.

Use the top command to check Tomcat, MySQL, MongoDB, Nginx, Fastdfs, Redis ... and other applications, have not found a high occupancy situation.

Helpless, on the Internet to see the above method, record down, first emergency use it.

Description

Remember to perform the sync command before releasing the cache to prevent data loss.

 Free Pagecache:  # echo 1 >/proc/sys/vm/drop_cachesfree  dentries and inodes:   # echo2 >/proc/sys/vm/drop_cachesfree  Pagecache, Dentries and Inodes:# echo3 >/proc/sys/vm/drop_caches

Literacy:

total--Total Physical memory used--used memory, this value is generally larger because this value includesthe memory used by the cache + application free-- Completely unused memory shared--application shared memory buffers--cache, mainly used for directory aspects, Inode value, etc. (LS Large directory can see this value increased) cached--cache for open files

Clean cache under Linux to free up memory