Is there a recommended maximum for how long rollback data is kept? Does this have any impact on performance?
Yes, the amount of rollback data will impact the performance of database writes. The amount of data depends entirely on the size and performance of your database server.
I recommend keeping as little rollback data as possible and implementing a full backup plan for older data. If you don't need instantaneous access to 3-month old data, store less than 3 months and restore backups when required. If you find yourself constantly needing to access old versions of pages, invest in a god DB server to support more data.
What would you recommend as a good DB server?
I cant give hardware recommendations on the forums. They are completely dependent on your site and usage patterns. You can talk to Squiz and work out the kind of hardware that best fits your system.
A suggestion,
Update the documentation on: http://matrix.squiz.net/resources/upgrading/rollback-managemen
running:
$ php scripts/rollback_management.php -s /path/to/matrix --reset-rollback
does not clear the files on the file system. I ran the following to clear the data in the database and the files on the file system.
$ php ./scripts/rollback_management.php -s /var/www/mysource_matrix -f 0d
$ php ./scripts/rollback_management.php -s /var/www/mysource_matrix --reset-rollback
Someone with more experience can perhaps point out if the order of running these commands matters, or if there are a different set of options to use when clearing both the database entries and the files.
Old file versions are kept regardless of the rollback settings, so we don't include that in the reset command, although your rightly show that the script can be used to remove old file versions.
The order itself can be important. Ideally, you don't want records in your DB pointing to files that are missing from your file system. So it is best to clear the files first and then clear DB records as you are doing. This means that there may be some file versions that do not have corresponding DB entries, but that is not critical because the DB is the authoritative source.
[quote]Old file versions are kept regardless of the rollback settings, so we don't include that in the reset command, although your rightly show that the script can be used to remove old file versions.
The order itself can be important. Ideally, you don't want records in your DB pointing to files that are missing from your file system. So it is best to clear the files first and then clear DB records as you are doing. This means that there may be some file versions that do not have corresponding DB entries, but that is not critical because the DB is the authoritative source.[/quote]
Thanks.
Does removing rollback data affect assets that are up for review? By affect, I mean, are any changes lost?
No. The rollback data is different from the Up For Review and Safe Edit systems.