Hot Backup of MySQL on a Linux VM From a Linux guest virtual machine

Written by: Ricky El-Qasem Senior Systems Engineer Veeam Software

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Hot Backup of MySQL on a Linux VM

CONTENTS

EXECUTIVE SUMMARY .....................................................................................................................................3 CONCEPT......................................................................................................................................................................4

OPTION 1. SUSPEND MYSQL SERVICE ...................................................................................... 4 OPTION 2. USE ONLINE DUMP .................................................................................................. 4

WALKTHROUGH.....................................................................................................................................................5 ASSUMPTIONS ............................................................................................................................ 5 SUSPEND MYSQL SERVICE......................................................................................................... 5 USE ONLINE DUMP .................................................................................................................... 7

ABOUT VEEAM ..................................................................................................................................................... 10

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Hot Backup of MySQL on a Linux VM

EXECUTIVE SUMMARY As more organisations move to virtualisation to facilitate core infrastructure, they look to the eco-system vendors to provide necessary core services, such as backup. Who better to help them meet those requirements than the virtualisation vendors themselves? This document describes the process required to take a consistent backup of MySQL running in a Linux virtual machine guest.

VMware enhanced the ability to take offline snapshots for the backup of virtual machines with the advent of VCB (VMware Consolidated Backup) and more recently the vStorage API for data protection. These tools allow third-party vendors to make use of API calls to produce LAN-free consistent snapshots of virtual machines. This is achieved by providing a block list to the backup proxy allowing for access of the virtual machine’s disk subsystem. The block list is presented across a Storage Area Network (SAN)/ Network Attached Storage (NAS), Fibre channel, ISCSI or NAS, allowing backup I/O to occur away from the production LAN orientated traffic. The result of these API calls is an Agentless live image-level copy of the virtual disks, or an Agentless file-level mount of the virtual disks. With Microsoft database centric applications like Active directory, SQL and Exchange a transaction consistent backup of these applications is possible with the use of Microsoft Volume Shadow copy Services aka VSS. During backup and at the point the snapshot is created, backup vendors are able to interface with VSS to place these applications in a temporary consistent state just for the period of the snapshot creation. Unfortunately MySQL is not VSS aware especially in a non-Microsoft operating system like Linux so a new approach has to be taken to produce a transaction consistent backup of MySQL databases.

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Hot Backup of MySQL on a Linux VM

CONCEPT The approach described here entails the use of activated scripts local to the MySQL database. VMware has the ability to run a script to perform actions before the snapshot is created which is known as the pre-freeze-script and the ability to run a script to perform actions after the snapshot is created which is known as the post-thaw-script. Virtual machine snapshots are used to release the file lock on the virtual disk which enables backup vendors to take backups of the virtual disk even while the virtual machine is powered on and running. The snapshot is created very quickly so the time required between the pre-freeze-script running and the post-thaw-script running is minimal, a few minutes even a few seconds. We have 2 options to consider to achieve database consistency:

Option 1. Suspend MySQL service The MySQL service is stopped for a few seconds while the snapshot is created then started again and is described in Method 1.

Advantage: It's quick and easy and will allow you to take a transaction of all databases without additional disk usage local to the MySQL server.

Disadvantage: For a brief period of time no databases running on the MySQL server will be available which may not be suitable for applications that need 100% uptime.

Option 2. Use Online Dump An online dump of each database is taken using the mysqldump command which copies a database to storage accessible from the MySQL server and is described in Method 2.

Advantage: The dumped databases are in a transaction consistent state and this is achieved without stopping the MySQL service and allows for 100% uptime.

Disadvantage: Extra storage space is required to maintain a second copy of the database and process may take a considerable amount of time to achieve depending on the size of your databases.

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Hot Backup of MySQL on a Linux VM

WALKTHROUGH Assumptions To find this information useful it is assumed you meet the following prerequisites:

You are conversant with Linux & MySQL command-line You are happy with the concept of server virtualisation You understand the workings of the VCB framework & the vStorage API for

data protection A Windows version of this document will be outlined in a separate

document

Also please note that the information used in this document was retrieved by testing the concept with the follow software:

Virtual Machine running on vSphere 4.0 The guest operating system is Ubuntu 9.10 Linux version of MySQL 5.1.x

Suspend MySQL service When using this method we'll stop the MySQL service by executing a command in the pre-freeze-script and then start it again with a command in the post-thaw-script. The post-thaw-script will not run until the snapshot is created. The pre-freeze-script and post-thaw-script will only be able to run if you have the VMware tools running in your MySQL server so the first steps is to ensure the tools are installed and running properly. Remember the assumption listed above and please bear in mind that the steps list next may differ depending on your environment but should apply to must situations. If you already have the VMware tools up and running you could jump to Part2.

Install the VMware tools Install the VMware tools on Ubuntu server 9.10

Step1 The VMware tools installation will need a C compiler part way through installation so we need to pre-stage this by executing the following commands: sudo apt-get install build-essential sudo apt-get install linux-headers-`uname -r`

Please note ` symbol surrounding `uname –r` is the symbol usually next to the 1 key on your keyboard.

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Hot Backup of MySQL on a Linux VM

Step 2 Next install the VMware tools on to the virtual machine by clicking "Install /Upgrade VMware tools" under the virtual machines Guest menu:

Step 3 Next we have to mount the VMware tools CDrom and copy the appropriate install file in the tmp folder. Then we have to expand (unzip) the install files needed. We achieve all this by running the following commands: cd / mount cdrom cp /cdrom/*.gz /tmp/ cd /tmp tar xvzf VM*.gz cd vmware*

Step 4 Now we are ready to install the VMware tools. Unless you have a specific reason I would default all the questions by hitting the "enter " key making sure that where asked for a yes/no answer first that yes is typed. To start the install run the following command: sudo ./vmware-install.pl

Creating scripts Creating the pre-freeze-script and post-thaw-script.

Step 5 Next we have to create the pre-freeze-script and post-thaw-script files as they are not created by default. To do this run the "touch" command in the following way: sudo touch /usr/sbin/pre-freeze-script sudo touch /usr/sbin/post-thaw-script

Step 6 Next we have to edit the pre-freeze-script and insert the "service mysql stop" command. To do this you can use your favorite Linux text editor, I use nano for simplicity: sudo nano /usr/sbin/pre-freeze-script

From here type service mysql stop and save&exit by typing ctrl-X and choosing to save the file by typing Y and hitting "enter "

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Hot Backup of MySQL on a Linux VM

Step 7 Next we have to edit the post-thaw-script and insert the "service mysql start" command. sudo nano /usr/sbin/post-thaw-script

From here type service mysql start and save&exit by typing ctrl-X and choosing to save the file by typing Y and hitting "enter "

Step 8 At this point the scripts are not quite ready to run as one last thing step to happen before they can be used. The scripts are not executable as the execute bit needs setting on the file permissions.

To do this run the following command on both files: sudo chmod 777 /usr/sbin/pre-freeze-script sudo chmod 777 /usr/sbin/post-thaw-script

Note: The "chmod" command is used to set the execute bit but the parameter "777" used also relaxes the file security permission on these files so you may want to review this and use something more restrictive settings.

Finally Now you are ready to perform your backup and Veeam backup will initiate the VMware snapshot component which will in-turn process the scripts as described early.

Use Online Dump Using this method a pre-freeze-script is used to issue the mysqldump command to dump a copy of a database to disk without disrupting the MySQL service. Whilst this method provides a way of taking a transaction consistent backup of databases and 100% uptime additional steps are needed when performing a restore. A consistent copy of the database may need to be restored from database dump you create with the pre-freeze-script. The pre-freeze-script will only be able to run if you have the VMware tools running in your MySQL server so the first steps is to ensure the tools are installed and running properly. Remember the assumption listed above and please bear in mind that the steps list next may differ depending on your environment but should apply to must situations. If you already have the VMware tools up and running you could jump to Part2.

Install the VMware tools Install the VMware tools on Ubuntu server 9.10

Step1 The VMware tools installation will need a C compiler part way through installation so we need to pre-stage this by executing the following commands: sudo apt-get install build-essential sudo apt-get install linux-headers-`uname -r`

Please note ` symbol surrounding `uname –r` is the symbol usually next to the 1 key on your keyboard.

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Hot Backup of MySQL on a Linux VM

Step 2 Next install the VMware tools on to the virtual machine by clicking "Install /Upgrade VMware tools" under the virtual machines Guest menu:

Step 3 Next we have to mount the VMware tools CDrom and copy the appropriate install file in the tmp folder. Then we have to expand (unzip) the install files needed. We achieve all this by running the following commands: cd / mount cdrom cp /cdrom/*.gz /tmp/ cd /tmp tar xvzf VM*.gz cd vmware*

Step 4 Now we are ready to install the VMware tools. Unless you have a specific reason I would default all the questions by hitting the "enter " key making sure that where asked for a yes/no answer first that yes is typed. To start the install run the following command: sudo ./vmware-install.pl

Creating scripts Creating the pre-freeze-script and post-thaw-script.

Step 5 Next we have to create the pre-freeze-script and post-thaw-script files as they are not created by default. To do this run the touch command in the following way: sudo touch /usr/sbin/pre-freeze-script sudo touch /usr/sbin/post-thaw-script

5 Ways VMware vSphere Improves Backup and Recovery

 

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Hot Backup of MySQL on a Linux VM

Step 6 Next we have to edit the pre-freeze-script and insert the "service mysql stop" command. To do this you can use your favorite Linux text editor, I use nano for simplicity: sudo nano /usr/sbin/pre-freeze-script

From here type sudo mysqldump –uroot –pveeam –h localhost test > test.sql and save&exit by typing ctrl-X and choosing to save the file by typing Y and hitting "enter " Note: I used the word "test" to represent the name of my database whilst –uroot is the user prompt and -pveeam is the password. The test.sql is the dump of the database so you could use an appropriate path and file name.

Step 7 At this point the scripts are not quite ready to run as one last step needs to happen before they can be used. The scripts are not executable as the execute bit needs setting on the file permissions.

To do this run the following command on both files: sudo chmod 777 /usr/sbin/pre-freeze-script sudo chmod 777 /usr/sbin/post-thaw-script

Note: The "chmod" command is used to set the execute bit but the parameter "777" used also relaxes the file security permission on these files so you may want to review this and use something more restrictive settings.

Finally Now you are ready to perform your backup and Veeam backup will initiate the VMware snapshot component which will in-turn process the scripts as described early.

5 Ways VMware vSphere Improves Backup and Recovery

 

Page | 10

Hot Backup of MySQL on a Linux VM

ABOUT VEEAM Veeam Software, a VMware Technology Alliance Premier Partner, provides innova-tive software for managing VMware infrastructure. Veeam offers an award winning suite of tools to assist the VMware administrator, including Veeam Backup, the 2 in 1 backup and replication solution; Veeam Reporter Enterprise, to document virtual environments for capacity planning and chargeback; Veeam Configurator, offering Host Profiles today; and Veeam Monitor, for performance monitoring and alerting across multiple VirtualCenters. With its acquisition of nworks, Veeam’s products include connectors that incorporate VMware data into Microsoft System Center Operations Manager and HP Software Operations Manager. Learn more about Veeam Software by visiting www.veeam.com.