I have an EXT3 partition that holds only MySQL dbs. Of 2Tb I'm down to about 90Gb remaining. This should be enough to last me until the new budget starts (and I can get some more storage) but I'm wondering whether the lack of space is causing any problems for MySQL.
closed as not a real question by Chopper3, Michael Hampton♦, MadHatter, Ward, Wesley Nov 29 '12 at 17:40
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In some cases mysql can create on-disk temporary tables to perform huge complex joins. Sure you need enough free space on disk for that.
If you replicate your bases, binlogs are also stored on disk in addition to the usual files.
Also, we all can forget to turn off debug logging :)
If you are specifically asking if only having 90GB out if 2TB leff will cause MySQL to choke, the answer is no. MySQL will continue to run until the space is exhausted (either by the database files, innodblogs, or tmp tables, then it will stop responding to queries and it hit max connections pretty quick.
If you are using separate InnoDB tables, you can reclaim unused space by issuing an OPTIMIZE TABLE [table name]
For tmp tables, you can move to a ram drive say 1GB (if you have enough ram).
Create amount point: mkdir /var/ramdisk mount -t tmpfs none /var/ramdisk -o size=1024m