- Supported Caching Backends
- Cache Types
- Configuring Memory Caching
- Caching Exceptions
You can significantly improve ownCloud server performance by using memory caching. This is the process of storing frequently-requested objects in-memory for faster retrieval later. There are two types of memory caching available:
A PHP opcode Cache (OPcache): An opcode cache stores compiled PHP scripts so they don’t need to be re-compiled every time they are called. These compiled PHP scripts are stored in-memory, on the server on which they’re compiled.
A Data Cache: A data cache stores copies of data, templates, and other types of information-based files. Depending on the cache implementation, it can be either local, or specific, to one server, or distributed across multiple servers. This cache type is ideal when you have a scale-out installation.
The caching backends supported by ownCloud are:
APCu: This is a local cache for systems running PHP 5.6 and up. APCu 4.0.6 and up is required. Alternatively you can use the Zend OPCache. However, it is not a data cache, only an opcode cache.
Redis: This is a distributed cache for multi-server ownCloud installations. Version 2.2.6 or higher of the PHP Redis extension is required.
Memcached: This is a distributed cache for multi-server ownCloud installations.
You may use both a local and a distributed cache.
The recommended ownCloud caches are APCu and Redis.
If you do not install and enable a local memory cache you will see a warning on your ownCloud admin page.
If you enable only a distributed cache in your
PHP 5.6 and up include the Zend OPcache in core, and on most Linux distributions it is enabled by default. However, it does not bundle a data cache. Given that, we recommend that you use APCu instead. APCu is a data cache and is available in most Linux distributions.
# On RedHat/CentOS/Fedora systems running PHP 5.6 yum install rh-php56-php-devel pecl install apcu # On RedHat/CentOS/Fedora systems running PHP 7.0 yum install rh-php70-php-devel pecl install apcu # On Debian/Ubuntu/Mint systems apt-get install php-apcu
On Ubuntu 14.04 LTS, the APCu version is 4.0.2. This is too old to use with ownCloud, which requires ownCloud 4.0.6+. You can install 4.0.7 from Ubuntu backports with the following command:
After APCu’s installed, enable the extension by creating a configuration file for it, using the following commands.
cat << EOF > /etc/opt/rh/rh-php70/php.d/20-apcu.ini ; APCu php extension extension=apcu.so EOF
With that done, assuming that you don’t encounter any errors, restart Apache and the extension is ready to use.
Redis is an excellent modern memory cache to use for both distributed caching and as a local cache for transactional file locking, because it guarantees that cached objects are available for as long as they are needed.
The Redis PHP module must be at least version 2.2.6 or higher. If you are running a Linux distribution that does not package the supported versions of this module — or does not package Redis at all — see Installing Redis on other distributions.
|Debian Jessie users, please see this GitHub discussion if you have problems with LDAP authentication when using Redis.|
On Debian/Ubuntu/Mint run the following command:
apt-get install redis-server php5-redis
If you have Ubuntu 16.04 or higher:
apt install redis-server php-redis
The installer will automatically launch Redis and configure it to launch at startup.
If you’re running ownCloud on Ubuntu 14.04, which does not package the required version of
On RedHat, CentOS, and Fedora run the following commands to install Redis:
yum install rh-php70-php-devel rh-redis32-redis pecl install redis
Unlike on Debian-based distributions, Redis will not start automatically on RedHat, Centos, and Fedora. Given that, you must use your service manager to both start Redis, and to launch it at boot time as a daemon. To do so, run the following commands:
systemctl start rh-redis32-redis systemctl enable rh-redis32-redis
You can verify that the Redis daemon is running using either of the following two commands:
ps ax | grep redis netstat -tlnp | grep redis
When it’s running, enable the Redis extension by creating a configuration file for it, using the following commands.
cat << EOF > /etc/opt/rh/rh-php70/php.d/20-redis.ini ; Redis php extension extension=redis.so EOF
After that, assuming that you don’t encounter any errors, restart Apache and the extension is ready to use.
APCu is faster at local caching than Redis. If you have enough memory, use APCu for memory caching and Redis for file locking. If you are low on memory, use Redis for both.
These instructions are adaptable for any distribution that does not package the supported version, or that does not package Redis at all, such as SUSE Linux Enterprise Server and RedHat Enterprise Linux.
|The Redis PHP module must be at least version 2.2.6.|
apt-cache to see the available
php5-redis version, or the
version of your installed package:
apt-cache policy php5-redis
The Redis cache can be flushed from the command-line using the redis-cli tool, as in the following example:
sudo redis-cli SELECT <dbIndex> FLUSHDB
<dbIndex> is the number of Redis database where the cache is stored.
It is zero by default at ownCloud. To check what yours is currently set
to, check the
dbindex value in
config/config.php. Here’s an example
of what to look for:
'redis' => [ 'host' => 'localhost', // Can also be a unix domain socket => '/tmp/redis.sock' 'port' => 6379, 'timeout' => 0, 'password' => '', // Optional, if not defined no password will be used. 'dbindex' => 0 // Optional, if undefined SELECT will not run and will // use Redis Server's default DB Index. ],
Memcached is a reliable old-timer for shared caching on distributed servers. It performs well with ownCloud with one exception: it is not suitable to use with Transactional File Locking. This is because it does not store locks, and data can disappear from the cache at any time. Given that, Redis is the best memory cache to use.
|Be sure to install the memcached PHP module, and not memcache, as in the following examples. ownCloud supports only the memcached PHP module.|
On Debian/Ubuntu/Mint run the following command:
apt-get install memcached php5-memcached
The installer will automatically start
On RedHat/CentOS/Fedora run the following command:
yum install memcached php-pecl-memcache
It will not start Memcached automatically after the installation or on subsequent reboots as a daemon, so you must do so yourself . To do so, run the following command:
systemctl start memcached systemctl enable memcached
You can verify that the Memcached daemon is running using one of the following commands:
ps ax | grep memcached netstat -tlnp | grep memcached
With the extension installed, you now need to configure it, by creating
a configuration file for it. You can do so using the command below,
FILE_PATH with one from the list below the command.
cat << EOF > FILE_PATH ; Memcached PHP extension extension=memcached.so EOF
After that, assuming that you don’t encounter any errors:
Restart your Web server
Add the appropriate entries to
config.php(which you can find an example of below)
Refresh your ownCloud admin page
The Memcached cache can be flushed from the command-line using a range
of common Linux/UNIX tools, including
The following example uses telnet to login, run
the flush_all command, and logout:
telnet localhost 11211 flush_all quit
For more information see:
Memory caches must be explicitly configured in ownCloud by:
Installing and enabling your desired cache (whether that be the PHP extension and/or the caching server).
Adding the appropriate entry to ownCloud’s
See config_sample_php_parameters for an overview of all possible config parameters. After installing and enabling your chosen memory cache, verify that it is active by viewing the PHP configuration details.
To use APCu, add this line to
'memcache.local' => '\OC\Memcache\APCu',
With that done, refresh your ownCloud admin page, and the cache warning should disappear.
config.php configuration uses Redis for the local server
'memcache.local' => '\OC\Memcache\Redis', 'redis' => [ 'host' => 'localhost', 'port' => 6379, ],
For best performance add the following
'memcache.locking' => '\OC\Memcache\Redis',
If you want to connect to Redis configured to listen on an Unix socket, which is recommended if Redis is running on the same system as ownCloud, use this example configuration:
'memcache.local' => '\OC\Memcache\Redis', 'redis' => [ 'host' => '/var/run/redis/redis.sock', 'port' => 0, ],
Redis is very configurable; consult the Redis documentation to learn more.
Redis is very configurable; This example uses APCu for the local cache, Memcached as the distributed memory cache, and lists all the servers in the shared cache pool with their port numbers:
'memcache.local' => '\OC\Memcache\APCu', 'memcache.distributed' => '\OC\Memcache\Memcached', 'memcached_servers' => [ ['localhost', 11211], ['server1.example.com', 11211], ['server2.example.com', 11211], ],
Use APCu for local caching, Redis for file locking
'memcache.local' => '\OC\Memcache\APCu', 'memcache.locking' => '\OC\Memcache\Redis', 'redis' => [ 'host' => 'localhost', 'port' => 6379, ],
Use Redis for everything except a local memory cache. Use the server’s IP address or hostname so that it is accessible to other hosts:
'memcache.distributed' => '\OC\Memcache\Redis', 'memcache.locking' => '\OC\Memcache\Redis', 'memcache.local' => '\OC\Memcache\APCu', 'redis' => [ 'host' => 'server1', // hostname example 'host' => '126.96.36.199', // IP address example 'port' => 6379, ],
Transactional File Locking prevents simultaneous file saving.
It is enabled by default and uses the database to store the locking data. This places a significant load on your database. It is recommended to use a cache backend instead. You have to configure it in
config.php as in the following example, which uses Redis as the cache backend:
'filelocking.enabled' => true, 'memcache.locking' => '\OC\Memcache\Redis', 'redis' => [ 'host' => 'localhost', 'port' => 6379, 'timeout' => 0.0, 'password' => '', // Optional, if not defined no password will be used. ],
|For enhanced security it is recommended to configure Redis to require a password. See http://redis.io/topics/security for more information.|
If ownCloud is configured to use either Memcached or Redis as a memory cache, please be aware that you may encounter issues with functionality. When these occur, it is usually a result of PHP being incorrectly configured, or the relevant PHP extension not being available.
In the table below, you can see all of the known reasons for reduced or broken functionality related to caching.
If file locking is enabled, but the locking cache class is missing, then an exception will appear in the web UI
The application will not be usable
If file locking is enabled and the locking cache is configured, but the PHP module missing.
There will be a white page/exception in web UI. It will be a full page issue, and the application will not be usable
All enabled, but the Redis server is not running
The application will be usable. But any file operation will return a "500 Redis went away" exception
If Memcache is configured for
There will be a white page and an exception written to the logs, This is because autoloading needs the missing class. So there is no way to show a page