You have left a lot of information out. What plugins are you using? What theme are you using? To me without out know that information it sounds like a plugin is eating up the servers memory.
Hope this helps.
I use plugins: ShowBiz only
theme: jarida
everything was going good
I have adedicated server:
Processor 2x E5-2670 0 @ 2.60GHz
Ram 96 GiB
Disk 1 TB
Operating System OCS – CentOS 7 (latest)
when site stops I receive messages like this:
lfd on server.xxxxx.com: Excessive processes running under user xxxxx
Account: xxxxx
Process Count: 11 (Not killed):
User:xxxxx PID:3625 PPID:17927 Run Time:119(secs) Memory:209596(kb) exe:/usr/bin/php cmd:/usr/bin/php /home/xxxxx/public_html/index.php
User:xxxxx PID:4161 PPID:17700 Run Time:97(secs) Memory:209596(kb) exe:/usr/bin/php cmd:/usr/bin/php /home/xxxxx/public_html/index.php
User:xxxxx PID:4168 PPID:9176 Run Time:97(secs) Memory:209596(kb) exe:/usr/bin/php cmd:/usr/bin/php /home/xxxxx/public_html/index.php
User:xxxxx PID:5500 PPID:9075 Run Time:47(secs) Memory:209596(kb) exe:/usr/bin/php cmd:/usr/bin/php /home/xxxxx/public_html/index.php
User:xxxxx PID:6683 PPID:8998 Run Time:0(secs) Memory:207572(kb) exe:/usr/bin/php cmd:/usr/bin/php /home/xxxxx/public_html/index.php
User:xxxxx PID:6684 PPID:9421 Run Time:0(secs) Memory:208092(kb) exe:/usr/bin/php cmd:/usr/bin/php /home/xxxxx/public_html/index.php
User:xxxxx PID:6686 PPID:8840 Run Time:0(secs) Memory:208092(kb) exe:/usr/bin/php cmd:/usr/bin/php /home/xxxxx/public_html/index.php
User:xxxxx PID:6692 PPID:8824 Run Time:0(secs) Memory:207068(kb) exe:/usr/bin/php cmd:/usr/bin/php /home/xxxxx/public_html/index.php
User:xxxxx PID:6693 PPID:17937 Run Time:0(secs) Memory:207068(kb) exe:/usr/bin/php cmd:/usr/bin/php /home/xxxxx/public_html/index.php
User:xxxxx PID:6698 PPID:17919 Run Time:0(secs) Memory:193884(kb) exe:/usr/bin/php cmd:/usr/bin/php /home/xxxxx/public_html/index.php
User:xxxxx PID:6705 PPID:23865 Run Time:0(secs) Memory:191152(kb) exe:/usr/bin/php cmd:/usr/bin/php /home/xxxxx/public_html/index.php
thanx alot for your interest
It sounds like you may have some damaged theme or wp files. Do you have the same issue with the server crashing when you temporarily switch to the 2015 theme?