Thread:Project:Support desk/Getting slammed by bots - countermeasures?

I have a fairly no-frills Mediawiki installation on a server with several other domains - this week have been having problems with the entire server running out of RAM, MySQL crashing, etc. Just got off the phone with tech support & we narrowed much of the issue down to a substantial & sustained onslaught of spambots on my wiki.

I'm fairly new to the software, so am looking for the proper solutions to this. Right away I disabled new signups using the "$wgGroupPermissions['*']['createaccount'] = false;" line in Local Settings. Any other extensions or settings that can help with this?

Thanks in advance for any help.