How to clear the cache on CENTOS?

Question

CentOS

Worth vestaCP.
on centos.
I log in as root via ssh
and enter:
echo 1 > /proc/sys/vm/drop_caches
echo 2 > /proc/sys/vm/drop_caches
echo 3 > /proc/sys/vm/drop_caches
writes:
[[email protected] ~]# echo 1 > /proc/sys/vm/drop_caches
bash: /proc/sys/vm/drop_caches: Permission denied
[[email protected] ~]# echo 2 > /proc/sys/vm/drop_caches
bash: /proc/sys/vm /drop_caches: Permission denied
[[email protected] ~]# echo 3 > /proc/sys/vm/drop_caches
bash: /proc/sys/vm/drop_caches: Permission denied

Answer 1

Not in a container. Use kvm or xen to access the kernel.