> Why not use a regular database for this (can be as simple as an sqlite file, depending on your needs)
A lot of depends on the scale and load pattern (e. g. ratio of active and inactive sessions). For a small scale sqlite could be a good choice.
Storing session in a regular DB (say Postgres) could be more expensive (hardware wise) than in Redis and there are cases when the load is high enough to matter but the budged is not unlimited (to use a DB at any cost). Also redundancy with a Redis cluster is easier than with Postgres. I don't think Redis always better, but at some load patterns it is.
> or the default thingy that comes with your framework or programming language?
Default PHP session store is files in /tmp - works for a home page but if load is high it explodes (millions files in /tmp is too slow to work with).
A lot of depends on the scale and load pattern (e. g. ratio of active and inactive sessions). For a small scale sqlite could be a good choice.
Storing session in a regular DB (say Postgres) could be more expensive (hardware wise) than in Redis and there are cases when the load is high enough to matter but the budged is not unlimited (to use a DB at any cost). Also redundancy with a Redis cluster is easier than with Postgres. I don't think Redis always better, but at some load patterns it is.
> or the default thingy that comes with your framework or programming language?
Default PHP session store is files in /tmp - works for a home page but if load is high it explodes (millions files in /tmp is too slow to work with).