dino

How do I backup MySQL in Linux?

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1. Copying from the mysql directory

By default, MySQL databases on servers that use Linux are stored in the following directory:

/var/lib/mysql/

If you shut down the mysqld service first, you can copy your databases to an example /backup directory using the following command:

cp –Rp /var/lib/mysql/*.* /backup

The –R switch for the cp command means recursive, which you want to use because each database is in a separate directory. The –p switch is for permissions, which will maintain the permissions of what is copied.

You generally want to shutdown the mysqld service before using the above method because if a database is copied while it is actively being used, the resulting backup will be corrupt and therefore worthless. If you are certain none of the databases are not being used at the time, you can use the above command.

2. The mysqldump command

The mysqldump command lets you back up both individual databases and all databases on a server without having to shutdown the mysqld service. Because of this ability to make backups while still keeping databases online, this method is preferred.

Individual databases

An example command that would let you back up a database named example to the directory /backup while logged in as root is as follows:

mysqldump example > /backup/example_backup.sql

Unless it is a small database, it is recommended that you then compress the resulting database backup in order to reduce the amount of time necessary to transfer the backup. The following command would compress the backup of the example database:

tar czvf /backup/example_backup.tar.gz /backup./example_backup.sql

All databases

If you have numerous databases and backing all of them up individually would be too time consuming, the following command will backup all MySQL databases on your server to the /backup directory:

mysqldump -A > /backup/databases.sql(or –all-databases)

The –A switch (“-all-databases” performs the same function) will dump any and all databases on the server.

Linux Memory Management

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Scenario: Customer is concerned that only 100MB of their 2GB of memory is as unused or free when running the free command. However, no processes appear to be consuming large amounts of memory, and the server is not running slow.

Cause: This is not a problem, but rather a result of the way linux manages its memory. On boot linux will typically display a large amount of free memory, as no processes have started to address it yet. Once processes run, Linux will cache that memory so it is quickly addressed for the next session. What this means is that on *most* linux distros, you’ll notice that a very small amount of memory is free, even though the machine is having no problems processing data (unlike, for instance a Windows server that would be quite slow with 150K of “free” memory). The best way to judge if the server is running low on memory, is if the swap space is being addressed. If the swap is occasionally hit, using a very small amount of memory, there is no cause for concern as that space will still be addressed. However, if a large amount of swap space is being used (50% or more) then the client may want to consider a memory upgrade.

Basically, the free memory isn’t the amount of memory that is not doing something, it’s the sum total of LowMem and HiMem that he kernel has left to address.

Mailbox unavailable or not local error messages – Plesk

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If you receive this error when adding a domain:

Unable to send notification: mail() failed: SMTP server response: 550 Requested action not taken: mailbox unavailable or not local

then you need to add a valid mailbox to your Plesk admin setup. To resolve this issue log into Plesk and click on:

Server
Edit (under personal information)
Replace the email address with a valid, working address.

Keep in mind this error shouldn’t prohibit you from creating a site, it is just notifying you that the “site created” email will not be sent.

How to add GD support to PHP on a Linux server with Plesk

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Adding GD graphic libraries support to php on your linux server with Plesk is relatively simple.

First, log into your server using ssh to get to a command line prompt.

Second, type the following command to install a version of php with GD support:

up2date php-gd

Third, restart your web service with this command:

service httpd restart

That is it. Your web server is now runing php with GD.

How do I retrieve the Plesk control panel password?

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You can always get the Plesk password if you have Administrative access to the server. If you have also lost administrative access to the server, refer to [How do I reset the password on my server]

For Windows,

1. From the Start menu, select Run.
2. Enter the following command:
“C:\Program Files\SWsoft\Plesk\admin\bin\plesksrvclient.exe” -get

For Linux,
1. Via SSH, run the following command:
cat /etc/psa/.psa.shadow

Assigning Name server IPs manually via SSH – cPanel

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Currently cPanel will start with eth0 and work through eth1 when you assign nameservers to your IPs via WHM. Unfortunately, this will automatically choose your management IP range first, which of course are non-routable. There are two work-arounds for this:

1: Create a fake nameserver record on your private IPs, and add an A record for that nameserver to your DNS. This is the fastest option, but not the best.

2: SSH to your server and edit /etc/nameserverips manually. An example file is blelow:

10.x.x.x=0
128.177.x.x1=ns1.my_cpanel_nameserver.com
128.177.x.x2=ns2.my_cpanel_nameserver.com
128.177.x.x3=0
128.177.x.x4=0
128.177.x.x5=0

Just replace the ‘0’ after the ‘=’ with your nameserver name. In this example, the first IP (10.x.x.x) is the management IP, and not used for nameservers. The next two IPs are public and assigned to two nameservers. The last three are public and not in use.

How can I compress my CPanel domlogs log files?

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Before setting up compression of your logs you will want to have cpanel run the stats as often as possible. This is so you do not miss any stats that would have been included were your logs not compressed before stats run.

To do this, login to WHM, and click on Tweak Settings under Server Configuration in the left menu. Scroll down to Stats and Logs, and then in the field next to “Number of days between processing log files and bandwidth usage (default 1, decimal values are ok):” enter ‘.5’.

This will cause your logs to be run twice a day, and should allow you to have up to date stats.

After doing this, we can begin to setup your domlogs compression. You will need to open an ssh shell to your server to complete this.

Change directories to /etc/logrotate.d/ and find the file named httpd. You will need to copy this file to a new file in the same directory:

root@cpdemo [/etc/logrotate.d]# cp httpd domlogs
root@cpdemo [/etc/logrotate.d]# ls -la domlogs
-rw-r–r– 1 root root 390 Nov 8 21:26 domlogs
root@cpdemo [/etc/logrotate.d]#

Now you will want to edit your new file to contain the following:

/usr/local/apache/logs/*.com /usr/local/apache/logs/*.org /usr/local/apache/logs/*.net {
missingok
notifempty
size=200M
rotate 2
compress
sharedscripts
postrotate
/bin/kill -HUP `cat /usr/local/apache/logs/httpd.pid 2>/dev/null` 2> /dev/null || true
endscript
}

Just save your new file and you are done. Most linux distributions come default with a logrotate cronjob running nightly that will work with this configuration.

cPanel required ports list

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Cpanel required ports list

PortServiceProtocolDirectionNotes
20ftptcpinbound/outbound
21ftptcp,udpinbound/outbound
22sshtcpinbound
25smtptcpinbound/outbound
26smtptcpinbound/outbound
37rdatetcpoutbound
43whostcpoutbound
53DNStcp/udpinbound/outbound Inbound only needed if you run your own DNS server
80httptcpinbound/outbound
110pop3tcpinbound
113identtcpoutbound
143imap4tcpinbound
443httpstcpinbound
465smtptcp/ssl, tcp/udpinbound/outbound
873rsynctpc/udpoutbound
993imap4ssl tcpinbound
995pop3ssl tcpinbound
2082cpaneltcpinbound
2083cpanelssl tcpinbound
2086whmtcpinbound
2087whm ssltcpinbound
2089cp licensetcpoutbound
2095webmailtcpinbound
2096webmailssl tcpinbound
3306mysqltcpinboundOnly if you need to connect remotely
6666chattcpinbound

WHM shows all accounts as 0/unlimited quotas

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There are many possible causes of this issue, however most relate to quotas being enabled on the filesystem itself.
Some ways to check the most common errors are:

Quotas enabled in the filesysem

By default, quoatas are enabled in the kernel on all SoftLayer Linux and FreeBSD kernels. If you’ve compiled/installed your own kernel, you’ll need to verify that quotas are enabled.

— FreeBSD systems will need to add “options QUOTA” to their kernel configuration and recompile. They will then need to add “enable_quotas=”YES”” to their /etc/rc.conf file.

— To enable quotas on a certain partition, one will need to modify the /etc/fstab file by adding usrquota (or grpquota if one desires the quota to pertain to an entire group rather than an individual user) to the options column (e.g. “LABEL=/home /home ext3 defaults,usrquota 0 0”).

[root@linux-test-server ~]# cat /etc/fstab
# This file is edited by fstab-sync – see ‘man fstab-sync’ for details
LABEL=/                 /                       ext3    defaults,usrquota        1 1
LABEL=/boot             /boot                   ext3    defaults        1 2
none                    /dev/pts                devpts  gid=5,mode=620  0 0
none                    /dev/shm                tmpfs   defaults        0 0
none                    /proc                   proc    defaults        0 0
none                    /sys                    sysfs   defaults        0 0
LABEL=SWAP-sda2         swap                    swap    pri=0,defaults        0 0
/usr/tmpDSK             /tmp                    ext3    defaults,noauto        0 0
/tmp             /var/tmp                    ext3    defaults,bind,noauto        0 0
[root@linux-test-server ~]#

— Once those entries are added, a reboot of the server should resolve the issue.

Run /scripts/fixquotas

Cpanel has it’s own tools to repair the quotas for it’s accounts. the command
#/scripts/fixquotas
run through ssh may resolve the issue.

Repquota

The command
#repquota -ua
will tell you if quotas are being reported for OS users at all.

Quotacheck

The command
#quotacheck -fv /home
will display the quotas for that filesystem, however the partition has to be unmounted first. It’s best to do this from Single User mode.