How to implement automatic backup of Memcached database in PHP

Memcached is a key-value storage system based on memory caching, which is commonly used to cache data in web applications. Since Memcached's data is stored in memory, special operations are required when backing up or migrating data. This article will introduce a method to realize automatic backup of Memcached database based on PHP, hoping to be helpful to Memcached users.

1. Backup method

Memcached is a distributed system whose data is stored on multiple nodes. Therefore, when backing up data, you need to back up all nodes. Memcached officially provides a backup tool, memcached-tool, which can be called through the command line for backup operations. However, this backup method requires manual operation and is not suitable for automatic backup.

In this case, we can use PHP to write automatic backup scripts. The specific implementation method is as follows:

1. Connect to Memcached and obtain the key value list

<?php
$mem = new Memcached();
$mem->addServer('localhost', 11211);
$keys = $mem->getAllKeys();

2. Traverse the key value list and back up the data

<?php
foreach ($keys as $key) {
    $value = $mem->get($key);
    $filename = './backup/'.$key.'.txt';
    file_put_contents($filename, $value);
}

In the above code, we first pass Memcached's getAllKeys() method obtains a list of all key values, then traverses the list and stores the value corresponding to each key into a text file.

3. Add scheduled tasks

In order to achieve automatic backup every day or every week, we need to add the backup script to the scheduled task. This can be achieved using the crontab command of the Linux system. Execute the following command in the Linux system:

$ crontab -e

Then add the following content in the editor:

0 0 * * * php /path/to/backup.php

This command means to execute the backup script once every day at zero o'clock. If weekly backup is required, you can modify it to:

0 0 * * 0 php /path/to/backup.php

This command means to execute the backup script every Sunday at 0:00.

2. Data recovery method

When backing up data, we save the values ​​corresponding to all keys into text files. For data recovery, you only need to traverse all text files and write the contents of each file into the corresponding key. The specific implementation method is as follows:

<?php
$backupFiles = glob('./backup/*.txt');

foreach ($backupFiles as $file) {
    $key = basename($file, '.txt');
    $value = file_get_contents($file);
    $mem->set($key, $value);
}

The above code traverses all backup files, obtains the corresponding key value through the file name, and writes the file content to Memcached. It should be noted that if the key value already exists, the original value will be overwritten.

3. Summary

This article introduces a method to realize automatic backup of Memcached database based on PHP, and explains the backup and recovery operations respectively. In this way, the security and reliability of Memcached data can be ensured, and the availability and stability of the system can be improved.

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