Hi. On Thu, Feb 27, 2020 at 03:11:10PM +0000, G.W. Haywood wrote: > As the box was still running Jessie I had to do the move in two bites. > First move from Jessie to Stretch, then from Stretch to Buster. The > entire process was a bit long-winded and spread over a couple of days, > but seemed to go smoothly enough. Immediately, the users started to > complain about performance. Not just a small reduction, but the sort > of thing that makes the whole system completely unusable. My estimate > after looking at the response on the desktop is several hundred times > slower than normal for this box. If you click on a message in the > list of messages presented by the mail client, instead of seeing the > message in under a second you can go and have a coffee break and still > get back before it's shown on the screen.
Just a wild guess, as I saw something similar after the upgrade to buster. Your users did not like new and shiny mq-deadline I/O scheduler. Have you tried its alternative, bfq? Barring that, have you tried lowering vm.dirty_ratio and vm.background_dirty_ratio sysctls? Reco
