We have one php application and mysql server running on one of our production server.
Mysql server is currently 4GB big with intention to grow up to tens or even up to hundreds of GB.
What am curious to find out is what are the best practices for backup of mysql database in condition that application must be live under any circumstance? What is better, to have mysql replication server on which we will run backup scripts or to run on live server? What is more likely to slow down We have possibility to add additional server(s) if needed. Where do I need to store mysql dumps? Is it suggested to ftp copy mysql backup files to remote server.
What is the best practice to organize web application backup if don't have problem with number of server instances?
MySQL backup methods are documented on MySQL documentation.
The ideal backup solution will be to use MySQL Enterprise Backup. This is a licensed product sold on Oracle store. It is very fast compared to mysqldump.
MySQL Enterprise Backup: A licensed product that performs hot backups
of MySQL databases. It offers the most efficiency and flexibility when
backing up InnoDB tables, but can also back up MyISAM and other kinds
of tables.
If you are looking for a free solution with MySQL community edition, then you can install another replication server and either run mysqldump to take backup or make a raw data backup. During backup on your replication server, your main master database will be running. Since your data is big or will get bigger, it is recommended to backup raw data files. It is basically a process of copying data and log files from disk. Details are explained on MySQL documentation.
For larger databases, where mysqldump would be impractical or
inefficient, you can back up the raw data files instead. Using the raw
data files option also means that you can back up the binary and relay
logs that will enable you to recreate the slave in the event of a
slave failure.
Finally, you should copy backup files to another physical disk on the same to recover from disk failures or to another physical server to easily recover from complete server failures.
Replication is something that protects against hardware errors, for example, a hard disk crashed.
Backup - protects against software errors, for example, due to the human factor, data has been deleted from a table.
It is definitely good practice to combine both of these technologies by running a utility to create a backup on a replica. This not only reduces the load on the product database, but also covers more recovery scenarios.
In case of a hardware error, you can restore the most up-to-date data from the replica, and in cases of data corruption, you can already consider about from the what date to use the backup for recovery. Well, if your both the main server and the replica fail, then the backup will also save you.
What is the best way to make backups?
mysqldump is a good solution for small databases. This is a utility for creating logical backups nad it is included to MySQL Server. At the output, the utility creates a .sql file to recreate the database.
For large databases, it is better to use a physical backup. There are two ways on how to do it.
mysqlbackup is a utility included with MySQL Enterprise Solution. As a result, you get a binary file. Such a backup is created much faster than using mysqldump and is less load on the server.
xtrabackup, from Percona, is a lot like the MySQL Enterprise backup utility, but it's free. A more detailed comparison can be found here.
How often the backups should be made?
The more often you make backups, the better, but you can't make many such backups - since you will run out of space in the backup storage. There are two ways:
Find a compromise between the frequency of backups and the duration of storage.
Use incremental backups. The above utilities support incremental backups, but the management of such backups is more complicated (read more here)
Where the backups should be stored?
Anywhere you prefer, but not in the same place as the MySQL Server. Overall, I think using cloud storage is a good choice. Almost everyone today has a command line interface.
How to automate a backup?
The process of creating regular backups should be automated, and a person should intervene in it only in case of failure. A good backup process should include the following steps:
Creating a backup copy
Compression\Encryption
Uploading to storage
Sending success\fail notification
Removing old backups from the storage (so that it does not overflow)
The simplest script that implements this can be found, for example, here.
Something else?
Yes, the most important thing is not to create a backup and then restore it. Therefore, it is best practice to regularly test the recovery scenarios.
Happy backups!
What is better, to have mysql replication server on which we will run backup scripts or to run on live server
It depends on your db size (and time needed to dump it using mysqldump) and your reliability requirements.
If your db is relatively small and mysqldump dumps it in seconds or in a few minutes then its ok to just run scheduled backups. For most cases it is sufficient to have a daily backup which runs at a time when your app is mostly idle (at night when you clients are sleeping). You can use a nice tool automysqlbackup for that: it cares about the scheduling and backup rotation, all you need to do is to add it as your cron task and set up its config once.
Setting up a replica is only needed if:
Your backup takes long time (dozens of minutes or hours) to complete so you can not just stop your service for that long.
You can not afford loosing any history in case of main db crash. E.g. if you process financial transactions you may want to ensure that nothing will be lost if master db server dies.
In this cases you may want a replica with backups. Though you must understand that adding replication adds a new layer of problems: replicas may go out of sync, silently crash (and you will not notice that as the master and your app is running fine) etc.
Related
I maintain a server that runs daily cron jobs to aggregate data sources and generate reports, accessible by a private Ruby on Rails application.
One of our data sources is a partial dump of one of our partner's databases. The partner runs an active application and the MySQL DB has hundreds of tables. They have given us read-only access to a relatively underpowered readonly slave of their application DB.
Because of latency issues and performance bottlenecking on their slave DB, we have been maintaining a limited local copy of their DB. We only need about 20 tables for our reports, so I only dump those tables. We also only need the data to a daily granularity, so realtime sync is not a requirement.
For a few months, I had implemented a nightly cron which streamed the dump of the necessary tables into a local production_tmp database. Then, when all tables were imported, I dropped production and renamed production_tmp to production. This was working until the DB grew to over 25GB, and we started running into disk space limitations.
For now, I have removed the redundancy step and am just streaming the dump straight into production on our local server. This feels a bit flimsy to me, and I would like to implement a safer approach. Also, currently doing the full dump/load takes our server over 2 hours, and I'd like to implement an approach that doesn't take as long. The database will only keep growing, so I'd like to implement something future proof.
Any suggestions would be appreciated!
I take it you have never heard of, or considered MySQL Replication?
The idea is that you do your backup & restore once, and then configure the replica to "subscribe" to a continuous stream of changes as they are made on the primary MySQL instance. Any change applied to the primary is applied automatically to the replica within seconds. You don't have to do the backup & restore procedure again, unless the replica gets damaged.
It takes some care to set up and keep working, but it's a much more efficient method of keeping two instances in sync.
#SusannahPotts mentions hot backup and/or incremental backup. You can get both of these features for free, without paying for MySQL Enterprise using Percona XtraBackup.
You can also consider using MySQL Transportable Tablespaces.
You'll need filesystem access to run either Percona XtraBackup or MySQL Enterprise Backup. It's not possible to use these physical backup tools for Amazon RDS, for example.
One alternative is to create a replication slave in the same network as the live system, and run Percona XtraBackup on that slave, where you do have filesystem access.
Another option is to stream the binary logs to another host (see https://dev.mysql.com/doc/refman/5.6/en/mysqlbinlog-backup.html) and then transfer them periodically to your local instance and replay them.
Each of these solutions has pros and cons. It's hard to recommend which solution is best for you, because you aren't sharing full details about your requirements.
This was working until the DB grew to over 25GB, and we started running into disk space limitations.
Some question marks "here":
Why don't you just increase the available Diskspace for your database? 25 GB seems nothing when it comes down to disk-space?
Why don't you modify your script to: download table1, import table1_tmp, drop table1_prod, rename table1_tmp to table1_prod; rinse and repeat.
Other than that:
Why don't you ask your partner for a system with enough performance to run your reports on? I'm quite sure, he would prefer this rather than having YOU download sensitive data every day to your "local site"?
Last thought (requires MySQL Enterprise Backup https://www.mysql.de/products/enterprise/backup.html):
Rather than dumping, downloading and importing 25 GB every day:
Create a full backup
Download and import
Use Differential or incremental backups from now.
The next day you download (and import) only the data-delta: https://dev.mysql.com/doc/mysql-enterprise-backup/4.0/en/mysqlbackup.incremental.html
As far as I was aware, for MS SQL, PostgreSQL, and even MySQL databases (so, I assumed, in general for RDBMS engines), you cannot simply back up the file system they are hosted on, but need to do an SQL-level backup to have any hope of internal consistency and therefore ability to actually restore.
But then answers like this and indeed the official docs referenced seem to suggest that one can just tar away on database data:
docker run --volumes-from dbdata -v $(pwd):/backup ubuntu tar cvf /backup/backup.tar /dbdata
These two ideas seem at odds with one another. Is there something special about how Docker works that makes it unnecessary to use SQL-level backups? If not, what am I missing in my understanding? (Why is something used as the official example when you can't use it to back up a production database? That can't be right...)
Under certain circumstances, it should be safe to use the image of a database on a disk:
The database server is not running.
All persistent data is on the disk system(s) being backed up (logs, tables spaces, temporary storage).
All components are restored together.
You are restoring the image to the same server on the same path.
The last condition is important, because some aspects of the database configuration may be stored in operating system files.
You need to do the backup within the database whenever the server is running. The server is responsible for the internal consistency of the data, and the disk image may not be complete or recoverable. If the server is not running, then the state of the database should be consistent in the persistent storage.
I am handling few databases that is growing very fast. Now it is around 12GB and in next few months it will cross 15GB. At this situation I only have the traditional backup process mysqldump running in cronjob. I found significant delay in backup and restore time (hours, even days) for the whole database. Knowing that physical backups are much faster than logical, I found these two, but cannot implement those because of some limitations and company policy.
MySQL Enterprise Backup : which is commercial
Percona XtraBackup : Percona came with this tool specially for Linux environments. And not all companies will agree to use 3rd party tools even though it is open source.
Please suggest any other better backup and restore mechanism for big database specially when the databases are mix of Innodb and MyISAM. Looking for some good suggestions on snapshots
I have personally used Percona XtraBackup toolset. It does some simple procedures to get all the committed data in innodb binlog when it finishes the normal storage. Reading about MySQL Enterprise Backup also can do this.
Incremental backups/snapshots can be made with both Percona XtraBackup and MySQL Enterprise, if that's what you're looking for.
Using a read-only slave, you can maintain separation of the read locks. This will keep your locks from being held on the master read if you backup using mysql free tools.
Another option if you have a slave is you can shut off the slave and rsync the data somewhere for backup.
First I would try using "--single-transaction" with mysqldump as long as all your tables are innodb and you aren't modifying table structure during dump. This will attempt to dump from a single point in time but only when it can be performed without locking your tables.
I haven't tried xtrabackup but it looks like that will do what you want as well.
You could also try setting up mysql replication and dumping from the slave.
Lastly LVM snapshots but that takes a bit more work.
I maintain big MySQL database. I need to backup it every night, but the DB is active all the time. There are queries from users.
Now I just disable the website and then do a backup, but this is very bad as the service is disabled and users don't like this.
What is a good way to backup the data if data is changed during the backup?
What is best practice for this?
I've implemented this scheme using a read-only replication slave of my database server.
MySQL Database Replication is pretty easy to set up and monitor. You can set it up to get all changes made to your production database, then take it off-line nightly to make a backup.
The Replication Slave server can be brought up as read-only to ensure that no changes can be made to it directly.
There are other ways of doing this that don't require the replication slave, but in my experience that was a pretty solid way of solving this problem.
Here's a link to the docs on MySQL Replication.
If you have a really large (50G+ like me) MySQL MyISAM only databases, you can use locks and rsync. According to MySQL documentation you can safely copy raw files while read lock is active and you cannot do it with InnoDB.
So if the goal is zero downtime and you have extra HD space, create a script:
rsync -aP --delete /var/lib/mysql/* /tmp/mysql/sync
Then do the following:
Do flush tables
Run script
Do flush tables with read lock;
Run script again
Do unlock tables;
On first run rsync will copy a lot without stopping MySQL. The second run will be very short, it will only delay write queries, so it is a real zero downtime solution.
Do another rsync from /tmp/mysql/sync to a remote server, compress, keep incremental versions, anything you like.
This partly depends upon whether you use innodb or myiasm. For innodb; mySQL have their own (which costs money) solution for this (innodb hot copy) but there is an open source version from Percona you may want to look at:
http://www.percona.com/doc/percona-xtrabackup/
What you want to do is called "online backup". Here's a pointer to a matrix of possible options with more information:
http://www.zmanda.com/blogs/?p=19
It essentially boils down to the storage backend that you are using and how much hardware you have available.
What do I have to consider when backing up a database with millions of entries? Are there any tools (maybe bundled with the MySQL server) that I could use?
Depending on your requirements, there's several options that I have been using myself:
if you don't need hot backups, take down the db server and back up on the file system level, i. e. using tar, rsync or similar.
if you do need the database server to keep running, you can start out with the mysqlhotcopy tool (a perl script), which locks the tables that are being backed up and allows you to select single tables and databases.
if you want the backup to be portable, you might want to use mysqldump, which creates SQL scripts to recreate the data, but which is slower than mysqlhotcopy
if you have a copy of the db at a certain point in time, you could also just keep the binlogs (starting at that point in time) somewhere safe. This can be very easy to do and doesn't interfere with the server's operation, but might not be the fastest to restore, and you have to make sure you don't miss part of the logs.
Methods I haven't tried, but that make sense to me:
if you have a filesystem like ZFS or are running on LVM, it might be a good idea to do a snapshot of the database by doing a filesystem snapshot, because they are very, very quick. Just remember to ensure a consistent state of your db during the whole operation, e. g. by doing FLUSH TABLES WITH READ LOCK (and of course, don't forget UNLOCK TABLES afterwards)
Additionally:
you can use a master-slave setup to replicate your production server to either a different machine or a second instance on the same machine and do any of the above to the replicated copy, leaving your production machine alone. Instead of running continously, you can also fire up the slave on regular intervals, let it read the binlog, and switch it off again.
I think, MySQL cluster and the enterprise licensed version have more tools, but I have never tried them.
Mysqlhotcopy is badly described - it only works if you use MyISAM, and it's not hot.
The problem with mysqldump is the time it takes to restore the backup (but it can be made hot if you have all InnoDB tables, see --single-transaction).
I recommend using a hot backup tool, like what is available in XtraBackup:
http://www.percona.com/docs/wiki/percona-xtrabackup:start
Watch out if using mysqldump on large tables using the MyISAM storage engine; it blocks selects while the dump is running on each table and this can take down busy sites for 5-10 minutes in some cases.
Using InnoDB, by comparison, you get non-blocking backups because of its row-level locking, so this is not such an issue.
If you need to use MyISAM, a common strategy is to replicate to a second MySQL instance and do the mysqldump against the replicated copy instead.
Use the export tab in phpMyAdmin. phpMyAdmin is the free easy to use web interface for doing MySQL administration.
I think mysqldump is the proper way of doing it.