How to check server load
If the server load is high then do the following tricks:
1) Top
check for the server load and watch for process
2) free -m
it will display the memory status
3)if a particular user is causing a high server load then use "ps U username": it will display the process that are running by the user .
4) Then you can take action against that user.
4) netstat -an |grep :80 |wc -l :
Show how many active connections there are to apache (httpd runs on port 80)
To check port open or not netstat -tnpl | grep httpd
5) netstat -ntu | awk '{print $5}' | cut -d: -f1 | sort | uniq -c | sort –n
netstat -anp |grep 'tcp\|udp' | awk '{print $5}' | cut -d: -f1 | sort | uniq -c | sort –n
netstat -anp |grep '80' | awk '{print $5}' | cut -d: -f1 | sort | uniq -c | sort -n
netstat -anp |grep '21' | awk '{print $5}' | cut -d: -f1 | sort | uniq -c | sort -n
netstat -anp |grep '3306' | awk '{print $5}' | cut -d: -f1 | sort | uniq -c | sort –n
netstat -utn | grep :80 | awk '{print $5}' | cut -d: -f1 | sort | uniq -c | sort -n | tail -10
mysqladmin -u root process list
check for the databases and suspend that user if any database is using high resources.
7)check /tmp if there is any process taking high resources : chown to root for that process and chmod 000 also if .sh process is running then chown it t0 root:root
8)if exim is taking high resources then check for exim logs : use this command :
replace :blackhole: : fail: -- /etc/valiases/*
General
Top –c d2
top –d 2
free –m : Memory status
w : Current users
ps –aufx : show cpu usages
netstat -ntu | awk '{print $5}' | cut -d: -f1 | sort | uniq -c | sort –n
netstat -plan|grep :25|awk {'print $5'}|cut -d: -f 1|sort|uniq -c|sort -nk 1
exim -bp | exiqsumm
ps aux | head -1;ps aux --no-headers| sort -rn +3 | head :
Use below mentioned command to get top memory consuming processes
ps aux | head -1;ps aux --no-headers | sort -rn +2
ps aux | head -1;ps aux --no-headers | sort -rn +2
If Exim causes
exim –bpc
shows the total no of email in qmail
eximstats -nr -ne /var/log/exim_mainlog
Total mail server report
pidof exim
shows no of exim pids running
exim -bpr | grep frozen | wc -l
Shows no of frozen emails
exiqgrep -z -i | xargs exim –Mrm
exim -bp | exiqgrep -i | xargs exim -Mrm
it deletes the FROZEN mails from the server
tail -f /var/log/exim_mainlog | grep public_html
check for spamming if anybody is using php script for sending mail through public_html
tail -f /var/log/exim_mainlog | grep /tmp
Used for checking for who is spamming through the /tmp
tail -3000 /var/log/exim_mainlog |grep 'rejected RCPT' |awk '{print$4}'|awk -F\[ '{print $2} '|awk -F\] '{print $1} '|sort | uniq -c | sort -k 1 -nr | head -n 5
It will display the IP and no of tries done bu the IP to send mail but rejected by the server.
netstat -plan|grep :25|awk {'print $5'}|cut -d: -f 1|sort|uniq -c|sort -nk 1
shows the connections from a certain ip to the SMTP server
exim -bp | exiqsumm | more
It shows the domain name and the no of emails sent by that domain
If spamming from outside domain then you can block that domain or email id on the server
pico /etc/antivirus.exim
Add the following lines:
if $header_from: contains "name@domain.com"
then
seen finish
endif
eximstats -nr -ne /var/log/exim_mainlog
Catching spammer
exim -bp | exiqsumm | more
exim -bpr | grep "<*@*>" | awk '{print $4}'|grep -v "<>" | sort | uniq -c | sort -n
That will show you the maximum no of email currently in the mail queue have from or to the email address in the mail queue with exact figure.
exim -bpr | grep "<*@*>" | awk '{print $4}'|grep -v "<>" |awk -F "@" '{ print $2}' | sort | uniq -c | sort -n
That will show you the maximum no of email currently in the mail queue have for the domain or from the domain with number.
Check if any php script is causing the mass mailing with
cd /var/spool/exim/input
egrep "X-PHP-Script" * -R
Just cat the ID that you get and you will be able to check which script is here causing problem for you.
To Remove particular email account email
exim -bpr |grep "ragnarockradio.org"|awk {'print $3'}|xargs exim -Mrm
If Mysql causes :
mysqladmin -u root processlist
mysqladmin version
watch mysqladmin proc
If Apache causes :
netstat -ntu | awk '{print $5}' | cut -d: -f1 | sort | uniq -c | sort –n
netstat -an |grep :80 |wc –l
netstat -n | grep :80 | wc -l;uptime ; netstat -n | wc –l
netstat –tupl
netstat –tupl
netstat -utn | grep :80 | awk '{print $5'} | cut -d: -f1 | sort | uniq -c | sort -n
Other Commands
pidof php
shows the PIDs for php
history | netstat
shows no of connection details
lsof -p pid
shows the details of pid
mysqladmin -u root processlist
watch mysqladmin proc
netstat -an |grep :80 |wc –l
very imp
netstat -ntu | awk '{print $5}' | cut -d: -f1 | sort | uniq -c | sort -n
netstat -na |grep :80 |sort
Use below mentioned command to get top memory consuming processes"
ps aux | head -1;ps aux --no-headers| sort -rn +3 | head
Use below command to get top cpu consuming processes:
ps aux | head -1;ps aux --no-headers | sort -rn +2 |more
You can check if any backup is going on, run the following commands:
# ps aux | grep pkg
# ps aux | grep gzip
# ps aux | grep backup
If any backup process is going on, kill that process.
We can trace the user responsible for high web server resource usage by the folowing command
cat /etc/httpd/logs/access_log | grep mp3
cat /etc/httpd/logs/access_log | grep rar
cat /etc/httpd/logs/access_log | grep wav etc
cat /etc/httpd/logs/access_log | grep 408 can be used to check for DDOS attacks on the server.
cat /etc/httpd/logs/access_log | grep rar
Port scanning :
root@server161 [/tmp]# nmap localhost
Starting Nmap 4.11 ( http://www.insecure.org/nmap/ ) at 2007-10-04 13:22 MYT
Interesting ports on localhost (127.0.0.1):
Not shown: 1664 closed ports
PORT STATE SERVICE
1/tcp open tcpmux
21/tcp open ftp
25/tcp open smtp
53/tcp open domain
80/tcp open http
110/tcp open pop3
111/tcp open rpcbind
143/tcp open imap
443/tcp open https
465/tcp open smtps
631/tcp open ipp
783/tcp open spamassassin
953/tcp open rndc
993/tcp open imaps
995/tcp open pop3s
3306/tcp open mysql
Nmap finished: 1 IP address (1 host up) scanned in 0.125 seconds
root@server161 [/tmp]#
netstat -anp |grep :3306
Hello Team,
Please do not restart apf or iptables on following servers,
202.75.39.88
203.121.68.68
203.121.73.130
DDOS ATTACK :
Who
top –d 2
ps -aux|grep HTTP|wc –l : It will show you no of http connections to the server
netstat -lpn|grep :80 |awk '{print $5}'|sort : It will helpful to check the no of connections from a certain ip
Check for the ips and block them with firewalls as apf/csf/iptables
For iptables : iptables -A INPUT -s <Source IP> -j DROP
For apf : apf –d ip_address
If load due to SPAMD:
Issue
The load issues on a cpanel 11 box (later versions too) because of spamd are quite common, sometimes they may take more than 90% of the CPU. Here are some ways to resolve it.
[edit] Solution
We can use the following steps to resolve the issue in a considerable manner.
1. Edit the /etc/mail/spamassassin/local.cf file
vi /etc/mail/spamassassin/local.cf
then add the following lines to it
a) use_bayes 0 (this will disable some spamassassin functionalities)
b) lock_method flock
(Uncomment these options, if they are commented)
2) Run scripts2/autofixer/spamd_dbm_fix
a) Log into WHM and use another URL as "http://your server IP:2086//scripts2/autofixer"
then type the script name "spamd_dbm_fix" and run
b) Or you can also do the same from server back end as follows.
# wget http://httpupdate.cpanel.net/autofixer/spamd_dbm_fix
# chmod 755 spamd_dbm_fix
# ./spamd_dbm_fix
3) Run the following lines of codes
# rm -f /home/*/.spamassassin/__db.bayes_toks.new
# rm -f /home/*/.spamassassin/*.lock
NOTE : If the load issue is related to a particular user then there is no need for running this,
you can simply enter into the '.spamassassin/' directory for that user and delete the
files '__db.bayes_toks.new' and *.lock.
4) Restart spam assassin (restart Exim)
5) :)Hope this will help you in such a situation.
: memory usage serverwide.
ps aux | awk '{print $4"\t"$11}' | sort | uniq -c | awk '{print $2" "$1" "$3}' | sort –nr
[root@emerald ~]# mymem
Memory Usage
------------
Current: 326.344 MB
Allocated: 492.012 MB
Guaranteed: 512 MB
Burstable: 768 MB
====================
5.1 1 spamd
0.7 1 spamd
0.6 1 /usr/bin/spamd
0.4 1 /usr/sbin/mysqld
0.2 1 cpsrvd
0.1 4 /etc/authlib/authProg
0.1 1 eximstats
0.1 1 cpdavd
0.1 1 cpbandwd
0.1 1 cpanellogd
0.1 1 cPhulkd
0.1 1 /usr/local/cpanel/bin/leechprotect
0.0 6 /usr/libexec/courier-authlib/authdaemond
0.0 4 /usr/sbin/courierlogger
0.0 4 -bash
0.0 3 sshd:
0.0 3 /usr/sbin/exim
0.0 3 /usr/lib/courier-imap/libexec/couriertcpd
0.0 2 sort
0.0 2 awk
0.0 11 /usr/local/apache/bin/httpd
0.0 1 xinetd
0.0 1 uniq
0.0 1 syslogd
0.0 1 pure-ftpd
0.0 1 ps
0.0 1 init
0.0 1 crond
0.0 1 chkservd
0.0 1 antirelayd
0.0 1 /usr/sbin/sshd
0.0 1 /usr/sbin/saslauthd
0.0 1 /usr/sbin/pure-authd
0.0 1 /usr/sbin/portsentry
0.0 1 /usr/sbin/named
0.0 1 /etc/authlib/authProg
0.0 1 /bin/sh
%MEM 1 COMMAND
[root@emerald ~]# mymem
====================================================
kill nobody process
ps aux | grep nobody | awk '{print $2}' | xargs kill -9
To see only the memory resources occupied by each category of processes, such as Apache httpd, MySQL mysqld or Java, use the following command:
ps aux | awk '{print $4"\t"$11}' | sort | uniq -c | awk '{print $2" "$1" "$3}' | sort -nr
====================================================
Okay, so everyone knows about ps. But I'll just highlight one of my favorite options:
ps -eo pid,%cpu,vsz,args,wchan
Shows every process, their pid, % of cpu, memory size, name, and what syscall they are currently executing. Nifty.
whereis locates source/binary and manuals sections for specified files. The supplied names are first stripped of leading pathname components and any (single) trailing
extension of the form .ext, for example, .c. Prefixes of s. resulting from use of source code control are also dealt with. whereis then attempts to locate the desired program in
a list of standard Linux places. For example find out where is ls command?
$ whereis ls
cd /var/spool/exim/input
egrep "X-PHP-Script" * -R
For netstat
netstat -nap | grep :110 | awk '{print $5}' | cut -d":" -f1 | sort | uniq -c | sort -nr | head
netstat -nap | grep :25 | awk '{print $5}' | cut -d":" -f1 | sort | uniq -c | sort -nr | head
netstat -n | grep :80 | wc -l;uptime ; netstat -n | wc -l
netstat -ntu | awk '{print $5}' | cut -d: -f1 | sort | uniq -c | sort -n
netstat -nap | grep :80 | awk '{print $5}' | cut -d":" -f1 | sort | uniq -c | sort -nr | head
root@server58 [~]# tail -f /var/log/slow.log
[root@server60 log]# tail -500 /var/log/mysql-slow-queries.log
ps -eo pcpu,pid,user,args | sort -k 1 -r | head -10
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