Without apparent rhyme or reason, one or two random domains (out of about 15) will suddenly choke on graphics. In other words, all the text loads normally, but the images load extremely slowly. Meanwhile, all other domains will continue to function normally.
There has been no reliable way to fix an occurence of this issue. Sometimes it seemed that resetting IIS one to ten times would fix it. Other times, rebooting the whole server (often multiple times) was required.
It’s taken a lot of effort to narrow this one down, but I’ve finally positively identified logging as the culprit. While one of the sites was exhibiting the symptom, I repeatedly disabled/enabled logging and the site was immediately affected each time.
I’ve triedlimiting the logging options to see if there is one or more specific options that are causing this, but it is an all-or-nothing thing.
If you can shed any light on this issue, your assistance would be greatly appreciated.