A while ago I setup smartd on all my servers do do a daily "Short Offline" test and a weekly "Extended Offline" test. The config for that is "-s (S/../.././00|L/../../7/04)".
Today I noticed one of my servers had a load average over 30 and was acting very slow. After some checking it was the result of all four disks in the raid5 going through the extended offline test. Should I even have these tests? Are the short offline ones enough to catch a failing disk in time to swap it out?
In case these are really needed I should probably stagger them throughout the week so they're not all happening at once.