phpguus/flysystem-raid

A flysystem driver for Redundant Array of Independent Disk configurations.

v1.1.2 2019-09-17 10:44 UTC

Requires

• php: ^7.2
• league/flysystem: ^1.0.55

Requires (Dev)

• phpunit/phpunit: ^8.3

MIT

• PHPGuus

README

Flysystem-raid provides RAID functionality across multiple flysystem filesystems.

Installation

Require the package using composer

composer require phpguus/flysystem-raid

Usage

RAID-0

RAID-0 is commonly known to provide striping of data.

We do not yet provide support for this kind of RAID configuration.

RAID-1

RAID-1 is commonly known to provide mirroring of data. Because we use the Flysystem abstraction, we can mirror data across any Flysystem, and make it redundantly available.

This is, in some respects, better than what a CDN can provide. A CDN normally covers only one vendor, for example DigitalOcean's Spaces CDN. This package, however, allows you to create mirrored data across many vendors, including a local disk.

If you want to keep files on your web server as well as in the cloud, this RAID configuration is all you need to do exactly that.

use Aws\S3\S3Client;
use League\Flysystem\Adapter\Local;
use League\Flysystem\AwsS3v3\AwsS3Adapter;
use League\Flysystem\Config;
use League\Flysystem\Filesystem;
use PHPGuus\FlysystemRaid\RaidOneAdapter;

include __DIR__ . '/vendor/autoload.php';

$s3Client = new S3Client([
    'credentials' => [
        'key'    => 'your-key',
        'secret' => 'your-secret'
    ],
    'region' => 'your-region',
    'version' => 'latest|version',
]);
$this->adapter = new RaidOneAdapter([
    new Filesystem(new Local('/local_files')),
    new Filesystem(new AWSS3Adapter($s3Client, 'your-bucket-name')),
]);

$this->adapter->write('myFirstFile.txt',
    'The quick brown fox jumps over the lazy dog.', new Config());

The file myFirstFile.txt is now written in both /local_files and in the AWS cloud.

Extending the mirror to a new location

Extending the mirroring of your RAID-1 configuration to a new location is very simple:

$this->adapter = new RaidOneAdapter([
    new Filesystem(new Local('/my_other_local_drive')),
    new Filesystem(new Local('/local_files')),
    new Filesystem(new AWSS3Adapter($s3Client, 'your-bucket-name')),
]);
$this->adapter->rebuildArray();

Replacing one location of the mirror

If you want to replace a location, because for example you change vendors from AWS to Digital Ocean, you need to perform a two step approach:

Step 1 is to make sure that your mirror is fully redundant:

$this->adapter = new RaidOneAdapter([
    new Filesystem(new Local('/local_files')),
    new Filesystem(new AWSS3Adapter($s3Client, 'your-bucket-name')),
]);
/* Ensure that both locations have identical data */
$this->adapter->rebuildArray();

Step 2 is to replace your AWS adapter configuration with a new one and to rebuild the array:

$s3Client = new S3Client([
    'credentials' => [
        'key'    => 'your-digital-ocean-key',
        'secret' => 'your-digital-ocean-secret'
    ],
    'region' => 'your-digital-ocean-region',
    'version' => 'latest|version',
]);
$this->adapter = new RaidOneAdapter([
    new Filesystem(new Local('/my_other_local_drive')),
    new Filesystem(new AWSS3Adapter($s3Client, 'your-digital-ocean-bucket-name')),
]);
$this->adapter->rebuildArray();

Knowing when to rebuild the array

$this->adapter->getMetadata($filePath); returns an array that has a key mirrors. The value of this key indicates the number of mirrors that exist for this file. If this is less than the number of locations configured in your adapter, you need to rebuild the array.

It would make sense to run a scheduled script that calls rebuildArray() at least once a day.

RAID-5

RAID-5 is commonly known to sustain the failure of one of its configured components through the use of a single parity disk that can be used to calculate missing data. At least 3 disks are necessary to provide RAID-5 protection, two are used for data, and one is used for parity calculations.

In modern implementations, RAID-5 parity data is stored across all three disks, as is the principle data.

We do not yet provide support for this kind of RAID configuration.

RAID-6

RAID-6, aka Double Parity RAID, is commonly known to sustain the failure of two of its configured components through the use of a two parity disks that can be used to calculate missing data. At least 4 disks are necessary to provide RAID-6 protection, two are used for data, and two are used for parity calculations.

In modern implementations, RAID-6 parity data is stored across all 4 disks, as is the principle data.

We do not yet provide support for this kind of RAID configuration.

RAID-10

This is combination of Striping and Mirroring, in which your data is striped across all disks, and each stripe (generally 8KiB) is mirrored.

We do not yet provide support for this kind of RAID configuration.

Contributing

Pull requests are welcome. For major changes, please open an issue first to discuss what you would like to change.

Please make sure to update tests as appropriate.

License

MIT