====== FS Cache ======
===== Cache takarítás =====
  * https://discuss.aerospike.com/t/tuning-kernel-memory-for-performance/4195

  * Flush RW cache: <code bash>
sync
</code>
  * To free pagecache: <code bash>
echo 1 > /proc/sys/vm/drop_caches
</code>
  * To free dentries and inodes: <code bash>
echo 2 > /proc/sys/vm/drop_caches
</code>
  * To free pagecache, dentries and inodes: <code bash>
echo 3 > /proc/sys/vm/drop_caches
</code>


===== Cache kikapcsolás =====
  * http://serverfault.com/questions/500874/ext3-with-no-write-cache

  * Mountolás: <code bash>
mount -o sync -t ext3 /dev/sda1 /mnt/foo
</code>
  * Újra mountolás: <code bash>
mount -o remount,sync /mnt/foo
</code>

===== cache állapota =====
  * https://medium.com/marionete/linux-disk-cache-was-always-there-741bef097e7f

<code>
vmtouch -v server.tar.gz                                                                                                                                                                          
server.tar.gz
[  ] 0/2

           Files: 1
     Directories: 0
  Resident Pages: 0/2  0/8K  0%
         Elapsed: 5.8e-05 seconds
</code>