lsof in action:

- Find who’s using a file:
lsof /path/to/file

- List of Open files Per Process:
lsof -p

- List of open Files Per User:
lsof -u

- List of Open File Descriptors:
lsof -d

- List of Open Internet protocols & ports:
lsof -i

- Directory Search :
lsof +D

- Find all open files by program’s name:
lsof -c

Examples:
# lsof -u admin,nasser
This will list all the files that are open by users admin and nasser.

# lsof -c httpd
It the list open files for processes whose name begins with httpd.

# lsof -a -u nasser -c tcsh
-a means AND
The output will be list of files opened by tcsh, which is run under nasser user privilege.

# lsof -u ^root
The ^ character before root username will negates the match and causes lsof print all open files by all users who are not root.

# lsof -p ^1010
List all open files by all the processes EXCEPT process with PID 1010.

# lsof -i tcp
List all TCP network connections.

# lsof -i udp
List all UDP network connections.

# lsof -i :22
The :22 option to -i makes lsof find processes using TCP or UDP port 25.

# lsof -i tcp:80
Finds who’s using a TCP port 80.

# lsof -a -u nasser -i
Will Find all network activity by user nasser.

# lsof -U
List all Unix domain socket files.

# lsof -g 1234
List all files for processes with a specific group id.

# lsof -r 5 -i tcp:22
The -r option makes lsof repeatedly list files until interrupted.

Have Fun.

Again Thanks to : MATT (http://thedooverguy.com/how-to-start-over-and-begin-a-new-life/)

ln -sf /usr/share/zoneinfo/UTC /etc/localtime

It worked again for a while and then I noticed again it has been changed to default config Again !!!

after a little googleing i find out that it is related to my configuration file here:

/etc/sysconfig/clock
I Just edit TimeZone on This file and it is ok now !

router#ping linux-server repeat 1000

Type escape sequence to abort.
Sending 1000, 100-byte ICMP Echos to linux-server, timeout is 2 seconds:
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!.!!!!.!!!.!!!!!..!!!.!!!!!!!!!!!!!!.!!!..!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!.!..!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!.!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!.!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!..!!.
Success rate is 97 percent (579/596), round-trip min/avg/max = 1/1/4 ms

as you can see Success rate is 97 percent , and i have 3% packet lost from Connected router !

after login to server , I saw this messages on syslog :

Feb 5 12:49:31 linux kernel: ip_conntrack: table full, dropping packet.

[root@linux ~]# sysctl net.ipv4.netfilter.ip_conntrack_max
net.ipv4.netfilter.ip_conntrack_max = 65,536

It looks like the conntrack database doesn’t have enough entries for your environment. Connection tracking by default handles up to a certain number of simultaneous connections. This number is dependent on you system’s maximum memory size.

You can easily increase the number of maximal tracked connections, but be aware that each tracked connection eats about 350 bytes of non-swappable kernel memory!

To increase this limit :

[root@linux ~]# echo "net.ipv4.netfilter.ip_conntrack_max = 131072" >> /etc/sysctl.conf
[root@linux ~]# sysctl -p

sub vcl_deliver {
...
...
    remove resp.http.X-Varnish;
    remove resp.http.Via;
    remove resp.http.Age;
    remove resp.http.X-Powered-By;
    unset obj.http.Server;
    set obj.http.Server = "Go Away";
...
...
}

sub vcl_error {
...
...
    unset obj.http.Server;
    set obj.http.Server = "Go Away";
...
...

I just add thease lines to my Varnish configuration:

...
...

sub vcl_recv {

...
...

        if ( req.request == "POST" ) {
                if (       req.url ~ "/upload/mainform.php"
                        || req.url ~ "/form1.php"
                        || req.url ~ "/form2.php"
                        || req.url ~ "/form3.php"
                        ) {
                        return (pass);
                } else {
                        error 403 ": Requested Method is not supported by this server.";

                }
        }
...
...

mysql> show master status;

DB-2:

mysql> STOP SLAVE;
Query OK, 0 rows affected (0.00 sec)

mysql> FLUSH TABLES WITH READ LOCK;
Query OK, 0 rows affected (0.00 sec)

mysql> UNLOCK TABLES;
Query OK, 0 rows affected (0.00 sec)

mysql> CHANGE MASTER TO
MASTER_HOST=’DB-1′,
MASTER_USER=’replication’,
MASTER_LOG_FILE=’bin.007733′,
MASTER_LOG_POS=824963644;
Query OK, 0 rows affected (0.00 sec)

mysql> start slave;
Query OK, 0 rows affected (0.00 sec)

http://www.dougreese.com/mysql-fatal-error-1236.html

- /etc/passwd - contains various pieces of information for each user account
- /etc/shadow – contains the encrypted password information for user’s accounts and optional the password aging information.
- /etc/group – defines the groups to which users belong
- /etc/gshadow – group shadow file (contains the encrypted password for group)
- /var/spool/mail – Generally user emails are stored here.
- /home – All Users data is stored here.

————-
Backup Routine:
————-

# mkdir /root/move/
# export UGIDLIMIT=500
# awk -v LIMIT=$UGIDLIMIT -F: '($3>=LIMIT) && ($3!=65534)' /etc/passwd > /root/move/passwd.mig
# awk -v LIMIT=$UGIDLIMIT -F: '($3>=LIMIT) && ($3!=65534)' /etc/group > /root/move/group.mig
# awk -v LIMIT=$UGIDLIMIT -F: '($3>=LIMIT) && ($3!=65534) {print $1}' /etc/passwd | tee - |egrep -f - /etc/shadow >  /root/move/shadow.mig
# cp /etc/gshadow /root/move/gshadow.mig
# tar -zcvpf /root/move/home.tar.gz /home
# tar -zcvpf /root/move/mail.tar.gz /var/spool/mail

————- Move Backup Files to New Linux Server: ————-

scp -r /root/move/*  nasser@linax.wordpress.com:/var/tmp

————- Restore : ————-

# mkdir /root/newsusers.bak

# cp /etc/passwd /etc/shadow /etc/group /etc/gshadow /root/newsusers.bak

# cd /var/tmp

# cat passwd.mig >> /etc/passwd

# cat group.mig >> /etc/group

# cat shadow.mig >> /etc/shadow

# /bin/cp gshadow.mig /etc/gshadow

# cd /

# tar -zxvf /var/tmp/home.tar.gz

# tar -zxvf /var/tmp/mail.tar.gz