ADM OS ASUSTOR with Squid Proxy error "warning your cache out of filedescriptor"


I have ASUSTOR NAS with ADM OS inside (factory default) and squid proxy inside the NAS, and 100 windows client connected with this proxy,

The problem:
-Cpu increase 100% when all of client active surfing in to internet, and squid not responding,
In cache log file i found “warning ! Your cache out of filedescriptor” it’s appear every minutes, when no clients to, finaly i try change the number of maximum file descriptor and i not found the directory of /etc/security/limits.conf and also the file, not listed on the ADM OS ASUSTOR, i try and try searching about this OS but found nothing about this problem,

-i try change in to sysctl.conf, after restarting the machine the value i changed before back again to default. back again and again.

I try with this tutorial

i can’t found the directory and file inside etc folder, etc/security/limits.conf

Can’t find limits.conf

ASUTOR is a custom Linux firmware. So you may not find generic files on it. Best way to get support for this is to contact ASUS directly.