I am using an AWS EC2 and my EC2 configuration is 4GB RAM and 100GB storage. But my server shows the following error after a few days fork: Cannot allocate memory on every command. When I use df command, it shows the output as below:
Filesystem Size Used Avail Use% Mounted on
udev 2.0G 0 2.0G 0% /dev
tmpfs 396M 41M 355M 11% /run
/dev/xvda1 97G 8.1G 89G 9% /
tmpfs 2.0G 4.0K 2.0G 1% /dev/shm
tmpfs 5.0M 0 5.0M 0% /run/lock
tmpfs 2.0G 0 2.0G 0% /sys/fs/cgroup
/dev/loop0 87M 87M 0 100% /snap/core/5145
/dev/loop1 13M 13M 0 100% /snap/amazon-ssm-agent/295
/dev/loop2 88M 88M 0 100% /snap/core/5328
/dev/loop3 13M 13M 0 100% /snap/amazon-ssm-agent/495
/dev/loop4 17M 17M 0 100% /snap/amazon-ssm-agent/734
tmpfs 396M 0 396M 0% /run/user/1000
We have set up cron after every one minute to store data in MongoDB.
After this error fork: Cannot allocate memory, my MongoDB gets crashed. Is this reason shown below I am getting error?
/dev/loop0 87M 87M 0 100% /snap/core/5145
/dev/loop1 13M 13M 0 100% /snap/amazon-ssm-agent/295
/dev/loop2 88M 88M 0 100% /snap/core/5328
/dev/loop3 13M 13M 0 100% /snap/amazon-ssm-agent/495
/dev/loop4 17M 17M 0 100% /snap/amazon-ssm-agent/734
Or any other reason? Please suggest me how to fix this problem.
UPDATED
Command ps aux --sort -rss output as shown below
USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND
ubuntu 14746 0.1 1.2 605972 50864 ? Sl Sep25 2:48 /usr/bin/python3 /home/folder_name/m2.py
ubuntu 16371 0.1 1.2 603916 50752 ? Sl Sep25 1:47 /usr/bin/python3 /home/folder_name/m2.py
ubuntu 1253 0.1 1.2 605972 50744 ? Sl Sep25 1:56 /usr/bin/python3 /home/folder_name/m2.py
ubuntu 21904 0.2 1.2 603912 50732 ? Sl Sep24 5:20 /usr/bin/python3 /home/folder_name/m2.py
ubuntu 25045 0.1 1.2 605976 50692 ? Sl Sep25 2:42 /usr/bin/python3 /home/folder_name/m2.py
ubuntu 4465 0.1 1.2 573212 50688 ? Sl Sep25 1:51 /usr/bin/python3 /home/folder_name/m2.py
ubuntu 26414 0.1 1.2 605972 50644 ? Sl Sep25 2:55 /usr/bin/python3 /home/folder_name/m2.py
ubuntu 31119 0.1 1.2 603912 50620 ? Sl Sep25 1:50 /usr/bin/python3 /home/folder_name/m2.py
ubuntu 30843 0.1 1.2 605972 50596 ? Sl Sep25 2:33 /usr/bin/python3 /home/folder_name/m2.py
ubuntu 6931 0.1 1.2 603912 50472 ? Sl Sep25 1:39 /usr/bin/python3 /home/folder_name/m2.py
ubuntu 27885 0.1 1.2 603908 50292 ? Sl Sep25 1:43 /usr/bin/python3 /home/folder_name/m2.py
ubuntu 14980 0.2 1.2 603912 50280 ? Sl Sep25 3:27 /usr/bin/python3 /home/folder_name/m2.py
ubuntu 16793 0.1 1.2 605972 50232 ? Sl Sep25 2:03 /usr/bin/python3 /home/folder_name/m2.py
ubuntu 31385 0.1 1.2 605976 49992 ? Sl Sep25 2:09 /usr/bin/python3 /home/folder_name/m2.py
ubuntu 13127 0.1 1.2 605972 49536 ? Sl Sep25 1:51 /usr/bin/python3 /home/folder_name/m2.py
ubuntu 30413 0.1 1.2 605980 49292 ? Sl Sep25 2:41 /usr/bin/python3 /home/folder_name/m2.py
ubuntu 3978 0.1 1.2 605972 49176 ? Sl Sep25 2:29 /usr/bin/python3 /home/folder_name/m2.py
ubuntu 22464 0.1 1.2 603912 49048 ? Sl Sep25 2:00 /usr/bin/python3 /home/folder_name/m2.py
ubuntu 21049 0.1 1.2 603912 48708 ? Sl Sep25 3:01 /usr/bin/python3 /home/folder_name/m2.py
ubuntu 20409 0.2 1.2 605972 48580 ? Sl Sep24 4:32 /usr/bin/python3 /home/folder_name/m2.py
ubuntu 19526 0.2 1.1 603912 48364 ? Sl Sep25 3:41 /usr/bin/python3 /home/folder_name/m2.py
ubuntu 21797 0.2 1.1 605980 48032 ? Sl Sep24 4:07 /usr/bin/python3 /home/folder_name/m2.py
ubuntu 25980 0.2 1.1 573200 47596 ? Sl Sep25 3:34 /usr/bin/python3 /home/folder_name/m2.py
ubuntu 25180 0.2 0.6 382020 25888 ? Sl Sep24 4:21 /usr/bin/python3 /home/folder_name/test.py
ubuntu 16764 0.2 0.6 857164 25616 ? Sl Sep24 7:08 /usr/bin/python3 /home/folder_name/test.py
ubuntu 3910 0.1 0.6 453324 25528 ? Sl Sep25 3:02 /usr/bin/python3 /home/folder_name/test.py
ubuntu 29769 0.1 0.6 439884 25396 ? Sl Sep25 2:30 /usr/bin/python3 /home/folder_name/test.py
ubuntu 14702 0.1 0.6 443968 25376 ? Sl Sep25 2:29 /usr/bin/python3 /home/folder_name/test.py
ubuntu 22640 0.1 0.6 446268 25284 ? Sl Sep25 1:39 /usr/bin/python3 /home/folder_name/test.py
ubuntu 10698 0.1 0.6 439284 24908 ? Sl Sep25 1:43 /usr/bin/python3 /home/folder_name/test.py
ubuntu 7118 0.1 0.6 382108 24856 ? Sl Sep25 1:44 /usr/bin/python3 /home/folder_name/test.py
ubuntu 20857 0.1 0.6 381968 24852 ? Sl Sep25 2:31 /usr/bin/python3 /home/folder_name/test.py
ubuntu 9652 0.1 0.6 382320 24820 ? Sl Sep25 2:17 /usr/bin/python3 /home/folder_name/test.py
ubuntu 25578 0.1 0.6 381984 24804 ? Sl Sep25 2:35 /usr/bin/python3 /home/folder_name/test.py
ubuntu 29743 0.1 0.6 382040 24772 ? Sl Sep25 1:39 /usr/bin/python3 /home/folder_name/test.py
ubuntu 31964 0.1 0.6 382024 24772 ? Sl Sep25 2:34 /usr/bin/python3 /home/folder_name/test.py
ubuntu 802 0.1 0.6 382060 24752 ? Sl Sep25 2:57 /usr/bin/python3 /home/folder_name/test.py
ubuntu 23609 0.1 0.6 382000 24752 ? Sl Sep25 2:45 /usr/bin/python3 /home/folder_name/test.py
ubuntu 2425 0.1 0.6 382060 24740 ? Sl Sep25 1:33 /usr/bin/python3 /home/folder_name/test.py
ubuntu 22551 0.1 0.6 381984 24740 ? Sl Sep25 2:45 /usr/bin/python3 /home/folder_name/test.py
ubuntu 11631 0.1 0.6 382060 24732 ? Sl Sep25 3:10 /usr/bin/python3 /home/folder_name/test.py
ubuntu 12422 0.2 0.6 382068 24720 ? Sl Sep24 5:29 /usr/bin/python3 /home/folder_name/test.py
ubuntu 6878 0.1 0.6 382056 24712 ? Sl Sep25 2:26 /usr/bin/python3 /home/folder_name/test.py
ubuntu 1296 0.1 0.6 382160 24704 ? Sl Sep25 1:59 /usr/bin/python3 /home/folder_name/test.py
ubuntu 30729 0.1 0.6 382360 24700 ? Sl Sep25 1:56 /usr/bin/python3 /home/folder_name/test.py
ubuntu 4985 0.1 0.6 382064 24692 ? Sl Sep25 3:25 /usr/bin/python3 /home/folder_name/test.py
ubuntu 9017 0.1 0.6 382048 24688 ? Sl Sep25 2:52 /usr/bin/python3 /home/folder_name/test.py
ubuntu 1885 0.1 0.6 382040 24680 ? Sl Sep25 1:52 /usr/bin/python3 /home/folder_name/test.py
ubuntu 3065 0.1 0.6 382016 24672 ? Sl Sep25 1:57 /usr/bin/python3 /home/folder_name/test.py
ubuntu 15708 0.1 0.6 382320 24672 ? Sl Sep25 1:58 /usr/bin/python3 /home/folder_name/test.py
ubuntu 6603 0.1 0.6 381968 24668 ? Sl Sep25 3:20 /usr/bin/python3 /home/folder_name/test.py
ubuntu 9581 0.2 0.6 455704 24664 ? Sl Sep24 5:36 /usr/bin/python3 /home/folder_name/test.py
ubuntu 16056 0.1 0.6 382024 24648 ? Sl Sep25 1:46 /usr/bin/python3 /home/folder_name/test.py
ubuntu 24948 0.1 0.6 381984 24644 ? Sl Sep25 3:02 /usr/bin/python3 /home/folder_name/test.py
ubuntu 10836 0.1 0.6 382104 24640 ? Sl Sep25 1:45 /usr/bin/python3 /home/folder_name/test.py
ubuntu 2865 0.1 0.6 381968 24632 ? Sl Sep25 2:35 /usr/bin/python3 /home/folder_name/test.py
ubuntu 3622 0.1 0.6 382024 24632 ? Sl Sep25 1:48 /usr/bin/python3 /home/folder_name/test.py
ubuntu 25284 0.1 0.6 381988 24628 ? Sl Sep25 2:41 /usr/bin/python3 /home/folder_name/test.py
ubuntu 18324 0.2 0.6 382060 24620 ? Sl Sep24 4:38 /usr/bin/python3 /home/folder_name/test.py
ubuntu 14285 0.1 0.6 381976 24616 ? Sl Sep25 1:46 /usr/bin/python3 /home/folder_name/test.py
ubuntu 29572 0.1 0.6 382064 24576 ? Sl Sep25 1:54 /usr/bin/python3 /home/folder_name/test.py
ubuntu 32483 0.1 0.6 381924 24576 ? Sl Sep25 1:45 /usr/bin/python3 /home/folder_name/test.py
ubuntu 6141 0.1 0.6 382296 24552 ? Sl Sep25 2:22 /usr/bin/python3 /home/folder_name/test.py
ubuntu 31282 0.1 0.6 381972 24552 ? Sl Sep25 1:38 /usr/bin/python3 /home/folder_name/test.py
ubuntu 17592 0.1 0.6 382088 24528 ? Sl Sep25 1:43 /usr/bin/python3 /home/folder_name/test.py
ubuntu 10968 0.1 0.6 382024 24520 ? Sl Sep25 2:38 /usr/bin/python3 /home/folder_name/test.py
ubuntu 20984 0.1 0.6 382060 24500 ? Sl Sep25 1:42 /usr/bin/python3 /home/folder_name/test.py
ubuntu 20978 0.1 0.6 381988 24496 ? Sl Sep25 3:19 /usr/bin/python3 /home/folder_name/test.py
ubuntu 24415 0.1 0.6 381972 24492 ? Sl Sep25 1:38 /usr/bin/python3 /home/folder_name/test.py
ubuntu 5606 0.1 0.6 390164 24480 ? Sl Sep25 3:33 /usr/bin/python3 /home/folder_name/test.py
ubuntu 8889 0.1 0.6 381972 24480 ? Sl Sep25 1:44 /usr/bin/python3 /home/folder_name/test.py
ubuntu 15768 0.1 0.6 381972 24452 ? Sl Sep25 1:38 /usr/bin/python3 /home/folder_name/test.py
ubuntu 5896 0.1 0.6 381972 24448 ? Sl Sep25 1:31 /usr/bin/python3 /home/folder_name/test.py
ubuntu 9024 0.1 0.6 382244 24444 ? Sl Sep25 1:50 /usr/bin/python3 /home/folder_name/test.py
ubuntu 5381 0.1 0.6 381972 24408 ? Sl Sep25 1:49 /usr/bin/python3 /home/folder_name/test.py
ubuntu 32471 0.1 0.6 382056 24400 ? Sl Sep25 1:52 /usr/bin/python3 /home/folder_name/test.py
ubuntu 31974 0.1 0.6 382092 24352 ? Sl Sep25 1:59 /usr/bin/python3 /home/folder_name/test.py
ubuntu 603 0.1 0.6 382056 24348 ? Sl Sep25 1:35 /usr/bin/python3 /home/folder_name/test.py
ubuntu 19188 0.1 0.5 382056 24224 ? Sl Sep25 1:41 /usr/bin/python3 /home/folder_name/test.py
ubuntu 15824 0.2 0.5 381968 24200 ? Sl Sep24 5:30 /usr/bin/python3 /home/folder_name/test.py
ubuntu 27547 0.1 0.5 382280 24096 ? Sl Sep25 2:06 /usr/bin/python3 /home/folder_name/test.py
ubuntu 25498 0.1 0.5 382036 23956 ? Sl Sep25 2:08 /usr/bin/python3 /home/folder_name/test.py
ubuntu 8147 0.2 0.5 381984 23848 ? Sl Sep24 5:02 /usr/bin/python3 /home/folder_name/test.py
ubuntu 1407 0.2 0.5 382060 23796 ? Sl Sep24 4:49 /usr/bin/python3 /home/folder_name/test.py
ubuntu 30229 0.1 0.5 381992 23756 ? Sl Sep25 2:00 /usr/bin/python3 /home/folder_name/test.py
ubuntu 17822 0.1 0.5 381980 23648 ? Sl Sep25 1:48 /usr/bin/python3 /home/folder_name/test.py
ubuntu 21288 0.1 0.5 390256 23592 ? Sl Sep25 2:25 /usr/bin/python3 /home/folder_name/test.py
ubuntu 7836 0.2 0.5 455804 23560 ? Sl Sep24 5:35 /usr/bin/python3 /home/folder_name/test.py
ubuntu 24801 0.2 0.5 382048 23532 ? Sl Sep24 5:41 /usr/bin/python3 /home/folder_name/test.py
ubuntu 11738 0.1 0.5 382036 23504 ? Sl Sep25 2:09 /usr/bin/python3 /home/folder_name/test.py
ubuntu 28161 0.1 0.5 446404 23484 ? Sl Sep25 2:17 /usr/bin/python3 /home/folder_name/test.py
ubuntu 3304 0.1 0.5 381988 23464 ? Sl Sep25 1:45 /usr/bin/python3 /home/folder_name/test.py
ubuntu 12358 0.1 0.5 382060 23344 ? Sl Sep25 2:41 /usr/bin/python3 /home/folder_name/test.py
ubuntu 21739 0.1 0.5 382060 23332 ? Sl Sep25 3:10 /usr/bin/python3 /home/folder_name/test.py
ubuntu 9802 0.2 0.5 381980 23228 ? Sl Sep24 4:23 /usr/bin/python3 /home/folder_name/test.py
ubuntu 25083 0.1 0.5 382096 23100 ? Sl Sep25 1:42 /usr/bin/python3 /home/folder_name/test.py
ubuntu 27147 0.1 0.5 382056 23060 ? Sl Sep25 1:47 /usr/bin/python3 /home/folder_name/test.py
ubuntu 21416 0.1 0.5 445172 23040 ? Sl Sep25 1:47 /usr/bin/python3 /home/folder_name/test.py
ubuntu 22407 0.1 0.5 447428 23028 ? Sl Sep25 2:37 /usr/bin/python3 /home/folder_name/test.py
ubuntu 16342 0.1 0.5 382060 23008 ? Sl Sep25 2:14 /usr/bin/python3 /home/folder_name/test.py
ubuntu 7718 0.1 0.5 382004 22972 ? Sl Sep25 2:36 /usr/bin/python3 /home/folder_name/test.py
ubuntu 30414 0.1 0.5 381968 22888 ? Sl Sep25 2:34 /usr/bin/python3 /home/folder_name/test.py
ubuntu 24367 0.2 0.5 382000 22736 ? Sl Sep24 4:02 /usr/bin/python3 /home/folder_name/test.py
ubuntu 32043 0.1 0.5 382060 22600 ? Sl Sep24 3:43 /usr/bin/python3 /home/folder_name/test.py
ubuntu 23225 0.1 0.5 382028 22584 ? Sl Sep25 1:48 /usr/bin/python3 /home/folder_name/test.py
ubuntu 20706 0.1 0.5 382060 22520 ? Sl Sep25 1:55 /usr/bin/python3 /home/folder_name/test.py
ubuntu 13525 0.1 0.5 381968 22492 ? Sl Sep25 2:06 /usr/bin/python3 /home/folder_name/test.py
ubuntu 8609 0.1 0.5 381984 22420 ? Sl Sep25 2:24 /usr/bin/python3 /home/folder_name/test.py
ubuntu 5340 0.1 0.5 382024 22320 ? Sl Sep25 1:46 /usr/bin/python3 /home/folder_name/test.py
ubuntu 1534 0.1 0.5 382056 22300 ? Sl Sep25 1:44 /usr/bin/python3 /home/folder_name/test.py
ubuntu 6618 0.1 0.5 455796 22228 ? Sl Sep24 3:38 /usr/bin/python3 /home/folder_name/test.py
ubuntu 8983 0.2 0.5 382044 22188 ? Sl Sep24 4:06 /usr/bin/python3 /home/folder_name/test.py
ubuntu 6528 0.2 0.5 382060 22128 ? Sl Sep24 4:46 /usr/bin/python3 /home/folder_name/test.py
ubuntu 20981 0.2 0.5 382064 22020 ? Sl Sep24 4:10 /usr/bin/python3 /home/folder_name/test.py
ubuntu 24469 0.1 0.5 381984 22020 ? Sl Sep25 3:32 /usr/bin/python3 /home/folder_name/test.py
ubuntu 22106 0.1 0.5 382028 21976 ? Sl Sep25 2:02 /usr/bin/python3 /home/folder_name/test.py
ubuntu 11596 0.2 0.5 381968 21804 ? Sl Sep24 4:37 /usr/bin/python3 /home/folder_name/test.py
ubuntu 16412 0.1 0.5 382044 21624 ? Sl Sep25 2:34 /usr/bin/python3 /home/folder_name/test.py
ubuntu 19820 0.1 0.5 434772 21552 ? Sl Sep25 2:36 /usr/bin/python3 /home/folder_name/test.py
root 15557 0.0 0.4 239840 19284 ? Ssl Sep04 23:19 /usr/lib/snapd/snapd
postgres 29110 0.0 0.3 293436 14704 ? S Sep19 0:10 /usr/lib/postgresql/9.5/bin/postgres -D /var/lib/postgresql/9.5/main -c config_file=/etc/postgresql/9.5/main/postgresql.conf
root 18090 0.1 0.2 308512 8636 ? Ssl Sep20 14:22 /snap/amazon-ssm-agent/734/amazon-ssm-agent
root 378 0.0 0.1 40736 7504 ? Ss Sep04 0:44 /lib/systemd/systemd-journald
root 5092 0.0 0.1 94892 6948 ? Ss 06:03 0:00 sshd: ubuntu [priv]
root 22334 0.0 0.1 94888 6936 ? Ss 06:38 0:00 sshd: ubuntu [priv]
root 11520 0.0 0.1 94888 6856 ? Ss 05:11 0:00 sshd: ubuntu [priv]
root 1126 0.0 0.1 272944 5568 ? Ssl Sep04 1:06 /usr/lib/accountsservice/accounts-daemon
ubuntu 5150 0.0 0.1 21480 5236 pts/0 Ss 06:03 0:00 -bash
root 1 0.0 0.1 37776 5048 ? Ss Sep04 0:43 /sbin/init
ubuntu 11534 0.0 0.1 45144 4584 ? Ss 05:11 0:00 /lib/systemd/systemd --user
root 1088 0.0 0.0 833712 4044 ? Ssl Sep04 0:15 /usr/bin/lxcfs /var/lib/lxcfs/
postgres 29113 0.0 0.0 293436 3952 ? Ss Sep19 0:11 postgres: writer process
ubuntu 24451 0.0 0.0 36580 3840 pts/0 R+ 06:42 0:00 ps aux --sort -rss
root 19311 0.0 0.0 5720 3512 ? S<Ls Sep24 0:15 /sbin/iscsid
root 1184 0.0 0.0 280628 3504 ? Ssl Sep04 0:00 /usr/lib/policykit-1/polkitd --no-debug
postgres 29115 0.0 0.0 293820 3444 ? Ss Sep19 0:17 postgres: autovacuum launcher process
ubuntu 5143 0.0 0.0 94892 3388 ? S 06:03 0:00 sshd: ubuntu@pts/0
postgres 29112 0.0 0.0 293436 3328 ? Ss Sep19 0:00 postgres: checkpointer process
ubuntu 11562 0.0 0.0 94888 3324 ? S 05:11 0:00 sshd: ubuntu
ubuntu 22369 0.0 0.0 94888 3324 ? S 06:38 0:00 sshd: ubuntu
root 1252 0.0 0.0 65508 3128 ? Ss Sep04 0:05 /usr/sbin/sshd -D
root 1079 0.0 0.0 28988 3048 ? Ss Sep04 0:03 /lib/systemd/systemd-logind
www-data 23982 0.0 0.0 125444 3008 ? S Sep24 0:17 nginx: worker process
root 454 0.0 0.0 43760 2860 ? Ss Sep04 0:02 /lib/systemd/systemd-udevd
root 17433 0.0 0.0 125116 2668 ? Ss Sep24 0:00 nginx: master process /usr/sbin/nginx -g daemon on; master_process on;
postgres 29114 0.0 0.0 293436 2660 ? Ss Sep19 0:11 postgres: wal writer process
root 888 0.0 0.0 16116 2648 ? Ss Sep04 0:01 /sbin/dhclient -1 -v -pf /run/dhclient.eth0.pid -lf /var/lib/dhcp/dhclient.eth0.leases -I -df /var/lib/dhcp/dhclient6.eth0.leases eth0
syslog 1070 0.0 0.0 260628 2412 ? Ssl Sep04 0:17 /usr/sbin/rsyslogd -n
root 1062 0.0 0.0 26068 2008 ? Ss Sep04 0:21 /usr/sbin/cron -f
root 601 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 1250 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 1294 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 1531 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 1883 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 2863 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 3063 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 3301 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 3620 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 3976 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 5338 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 5379 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 5603 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 6139 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 6526 0.0 0.0 49372 1972 ? S Sep24 0:00 /usr/sbin/CRON -f
root 6616 0.0 0.0 49372 1972 ? S Sep24 0:00 /usr/sbin/CRON -f
root 6875 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 6927 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 7116 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 7698 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 7834 0.0 0.0 49372 1972 ? S Sep24 0:00 /usr/sbin/CRON -f
root 8058 0.0 0.0 49372 1972 ? S Sep24 0:00 /usr/sbin/CRON -f
root 8607 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 8733 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 8885 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 8981 0.0 0.0 49372 1972 ? S Sep24 0:00 /usr/sbin/CRON -f
root 9015 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 9579 0.0 0.0 49372 1972 ? S Sep24 0:00 /usr/sbin/CRON -f
root 9800 0.0 0.0 49372 1972 ? S Sep24 0:00 /usr/sbin/CRON -f
root 10634 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 10834 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 11594 0.0 0.0 49372 1972 ? S Sep24 0:00 /usr/sbin/CRON -f
root 11629 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 11735 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 11975 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 12420 0.0 0.0 49372 1972 ? S Sep24 0:00 /usr/sbin/CRON -f
root 13125 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 13523 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 14283 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 14698 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 14976 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 15766 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 15822 0.0 0.0 49372 1972 ? S Sep24 0:00 /usr/sbin/CRON -f
root 16340 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 16369 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 16410 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 16762 0.0 0.0 49372 1972 ? S Sep24 0:00 /usr/sbin/CRON -f
root 16791 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 17820 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 18322 0.0 0.0 49372 1972 ? S Sep24 0:00 /usr/sbin/CRON -f
root 19185 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 19523 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 20405 0.0 0.0 49372 1972 ? S Sep24 0:00 /usr/sbin/CRON -f
root 20704 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 20855 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 20979 0.0 0.0 49372 1972 ? S Sep24 0:00 /usr/sbin/CRON -f
root 20982 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 21047 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 21286 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 21414 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 21795 0.0 0.0 49372 1972 ? S Sep24 0:00 /usr/sbin/CRON -f
root 22104 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 22401 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 22455 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 22638 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 23223 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 23606 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 24365 0.0 0.0 49372 1972 ? S Sep24 0:00 /usr/sbin/CRON -f
root 24413 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 24467 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 24799 0.0 0.0 49372 1972 ? S Sep24 0:00 /usr/sbin/CRON -f
root 24946 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 25043 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 25178 0.0 0.0 49372 1972 ? S Sep24 0:00 /usr/sbin/CRON -f
root 25282 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 25496 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 25576 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 25942 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 26412 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 27145 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 27882 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 29751 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 30227 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 30409 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 30410 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 30726 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 31109 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 31280 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 31383 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 31962 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 31972 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 32041 0.0 0.0 49372 1972 ? S Sep24 0:00 /usr/sbin/CRON -f
root 32469 0.0 0.0 49372 1972 ? S Sep25 0:00 /usr/sbin/CRON -f
root 16053 0.0 0.0 49372 1964 ? S Sep25 0:00 /usr/sbin/CRON -f
root 30840 0.0 0.0 49372 1964 ? S Sep25 0:00 /usr/sbin/CRON -f
root 14742 0.0 0.0 49372 1960 ? S Sep25 0:00 /usr/sbin/CRON -f
root 21899 0.0 0.0 49372 1960 ? S Sep24 0:00 /usr/sbin/CRON -f
root 4981 0.0 0.0 49372 1952 ? S Sep25 0:00 /usr/sbin/CRON -f
root 6600 0.0 0.0 49372 1948 ? S Sep25 0:00 /usr/sbin/CRON -f
ubuntu 11536 0.0 0.0 63320 1944 ? S 05:11 0:00 (sd-pam)
root 10966 0.0 0.0 49372 1888 ? S Sep25 0:00 /usr/sbin/CRON -f
root 17512 0.0 0.0 49372 1888 ? S Sep25 0:00 /usr/sbin/CRON -f
root 28158 0.0 0.0 49372 1888 ? S Sep25 0:00 /usr/sbin/CRON -f
root 9626 0.0 0.0 49372 1876 ? S Sep25 0:00 /usr/sbin/CRON -f
root 21599 0.0 0.0 49372 1852 ? S Sep25 0:00 /usr/sbin/CRON -f
root 32261 0.0 0.0 49372 1844 ? S Sep25 0:00 /usr/sbin/CRON -f
root 20753 0.0 0.0 49372 1840 ? S Sep25 0:00 /usr/sbin/CRON -f
root 25038 0.0 0.0 49372 1836 ? S Sep25 0:00 /usr/sbin/CRON -f
www-data 23981 0.0 0.0 125444 1780 ? S Sep24 0:26 nginx: worker process
root 15570 0.0 0.0 49372 1776 ? S Sep25 0:00 /usr/sbin/CRON -f
postgres 29116 0.0 0.0 148420 1776 ? Ss Sep19 0:06 postgres: stats collector process
Previously we had not installed nginx server for that we directly used crontab -e. In home directory we created one folder and in that folder we created two files and set crons and crontab -e command showed this
# m h dom mon dow command
*/10 * * * * /usr/bin/python3 /home/folder_name/m2.py
*/3 * * * * /usr/bin/python3 /home/folder_name/test.py
First /dev/loop* are virtual devices to mount disk images used by snapd service, it is perfectly normal that they are at 100% because these are read only.
The error fork: Cannot allocate memory means that your server is swapping (It runs out of free memory). I am not sure why you were looking at df output but this is not a disk space related issue, unless you are looking for a swap partition related solution but I guess that is not the case here.
You mentioned "my server shows error after few day's", which seems to be a symptom of memory leak occurring somewhere.
If I were you I would start by finding out what is using up all the memory. You can run the following command to sort processes by memory usage:
ps aux --sort -rss
You could also use top or htop for a real-time debugging session.
For your reference, mongodb (wiredTiger) by default uses the larger of either 60% of RAM minus 1GB, or 1GB.
Once you figure out the culprit you either want to fix it or accept the fact that you need more RAM. If it is the later case you might want to upgrade your instance to 8GB RAM or even more.