it stopped now
mem used 62692 free 56796

and buffers are 0. May be there is the problem?

- - - Updated - - -

cpu 7.6 usr 7.6 nic 81,8
load average 14.14.14.09 12.72 1/73 6607

mem usef 63356 free 54012
buffers 63220 54148
buffrers 136

it stopped again