zabbix_server [7327]: failed to open log file: [24] Too many open files
zabbix_server [7327]: failed to write [cannot accept incoming IPC connection: [24] Too many open files] into log file

[root@zabbix ~]# cat /proc/sys/fs/file-max
2097152

[root@zabbix ~]# cat /etc/sysctl.conf
# System default settings live in /usr/lib/sysctl.d/00-system.conf.
# To override those settings, enter new settings here, or in an /etc/sysctl.d/<name>.conf file
#
# For more information, see sysctl.conf(5) and sysctl.d(5).
dev.raid.speed_limit_min = 10000
dev.raid.speed_limit_max = 500000
vm.swappiness=1
 vm.vfs_cache_pressure=50
net.ipv4.ip_no_pmtu_disc=1
fs.file-max = 2097152

[root@zabbix ~]# vim /etc/security/limits.conf
* soft nproc 500000
 * hard nproc 500000
 * soft nofile 500000
 * hard nofile 500000

[root@zabbix ~]# su - zabbix -c 'ulimit -aHS' -s '/bin/bash'
su: warning: cannot change directory to /var/lib/zabbix: No such file or directory
core file size          (blocks, -c) 0
data seg size           (kbytes, -d) unlimited
scheduling priority             (-e) 0
file size               (blocks, -f) unlimited
pending signals                 (-i) 256296
max locked memory       (kbytes, -l) 64
max memory size         (kbytes, -m) unlimited
open files                      (-n) 500000
pipe size            (512 bytes, -p) 8
POSIX message queues     (bytes, -q) 819200
real-time priority              (-r) 0
stack size              (kbytes, -s) 8192
cpu time               (seconds, -t) unlimited
max user processes              (-u) 4096
virtual memory          (kbytes, -v) unlimited
file locks                      (-x) unlimited

[root@zabbix ~]# su - root -c 'ulimit -aHS' -s '/bin/bash'
core file size          (blocks, -c) 0
data seg size           (kbytes, -d) unlimited
scheduling priority             (-e) 0
file size               (blocks, -f) unlimited
pending signals                 (-i) 256296
max locked memory       (kbytes, -l) 64
max memory size         (kbytes, -m) unlimited
open files                      (-n) 500000
pipe size            (512 bytes, -p) 8
POSIX message queues     (bytes, -q) 819200
real-time priority              (-r) 0
stack size              (kbytes, -s) 8192
cpu time               (seconds, -t) unlimited
max user processes              (-u) 500000
virtual memory          (kbytes, -v) unlimited
file locks                      (-x) unlimited

LogFile=/var/log/zabbix/zabbix_server.log
LogFileSize=100
DebugLevel=3
PidFile=/var/run/zabbix/zabbix_server.pid
DBName=zabbix
DBUser=zabbix
StartPollers=750
StartPreprocessors=300
StartPollersUnreachable=200
StartTrappers=20
StartPingers=20
StartDiscoverers=250
StartTimers=3
SNMPTrapperFile=/var/log/snmptrap/snmptrap.log
HousekeepingFrequency=0
MaxHousekeeperDelete=1000
CacheSize=2048M
CacheUpdateFrequency=360
StartDBSyncers=2
HistoryCacheSize=512M
HistoryIndexCacheSize=128M
TrendCacheSize=128M
ValueCacheSize=512M
Timeout=30
UnreachablePeriod=360
UnavailableDelay=600
UnreachableDelay=120
AlertScriptsPath=/usr/lib/zabbix/alertscripts
ExternalScripts=/usr/lib/zabbix/externalscripts
LogSlowQueries=3000

[root@zabbix ~]# df -h
Filesystem      Size  Used Avail Use% Mounted on
/dev/md127      280G  8.9G  272G   4% /
devtmpfs         32G     0   32G   0% /dev
tmpfs            32G     0   32G   0% /dev/shm
tmpfs            32G  8.8M   32G   1% /run
tmpfs            32G     0   32G   0% /sys/fs/cgroup
/dev/md125      954G  179G  775G  19% /db
/dev/md126      2.0G  254M  1.8G  13% /boot
/dev/md2        1.6T  792G  783G  51% /mnt/lstorage
/dev/sdb3       200M     0  200M   0% /boot/efi2
/dev/sda1       200M  9.8M  191M   5% /boot/efi
tmpfs           6.3G     0  6.3G   0% /run/user/0

[root@zabbix ~]#  free
              total        used        free      shared  buff/cache   available
Mem:       65696748    24664656    39955132      460668     1076960    39956428
Swap:       5915644           0     5915644