My favorite Linux tool in DB work is ‘iostat -x’ (and I really really want to see whenever I’m doing any kind of performance analysis), yet I had to learn its limitations and properties. For example, I took 1s snapshot from a slightly overloaded 16-disk database box:
avg-cpu: %user %nice %system %iowait %steal %idle 8.12 0.00 2.57 21.65 0.00 67.66 Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s \ sda 7684.00 19.00 2420.00 498.00 81848.00 5287.00 \ avgrq-sz avgqu-sz await svctm %util 29.86 32.99 11.17 0.34 100.00
via dammit.lt
Thanks again to Mike Montano from Backtype. Great article to explain the simplest of Linux tools for diagnostics and troubleshooting.