[mythtv-users] ramfs for mysql
Simon Hobson
linux at thehobsons.co.uk
Wed Jan 4 19:02:11 UTC 2012
Josu Lazkano wrote:
>cp -R /var/lib/mysql /tmp/mysqltmp/
>chown -R mysql:mysql /tmp/mysqltmp/mysql/
You don't need to fiddle with ownerships and permissions - just use
the "-p" option to cp and it will preserve ownership and permissions.
>How could I copy all data on system stop and then copy again on system start?
If you need to ask that, then it may not be the right option for you.
You probably want to modify the mysql start/stop script. The system
calls this during startup & shutdown. You need to have the shutdown
option copy all the tables to a safe place after stopping the daemon,
and the startup option copy the safe copies to the ram disk before
starting the daemon.
If the system is running for a long time, you almost certainly want
to stop mysql from time to time and copy the tables to safe storage -
otherwise you risk losing potentially weeks or months of updates. If
you've modified the start/stop script, then this could be achieved by
a cronjob that just just stops and immediately starts mysql.
As a refinement, you could have the start option check to see if the
files on ram disk are the same age as those on real disk and skip the
copy - thus saving the copy back if the system hasn't been restarted
and so has the current DB files already on ram disk.
--
Simon Hobson
Visit http://www.magpiesnestpublishing.co.uk/ for books by acclaimed
author Gladys Hobson. Novels - poetry - short stories - ideal as
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