Ok, so I'm having this problem often - sometimes within an hour of reboot, sometimes it can be several days.
After much reading and searching of forums the only common response is that "it's a sympton of the server running low on memory".
I have 4 gigs, looking at the stats, I see that the usage hasn't been above 2.5 gigs, with free dropping to a minimum of .5 gigs (including cache).
Is free mem dropping to half a gig the cause of the web gui stopping then? If 0.5 gigs is low, then wouldn't the system reduce the cached amount to bring up the free amount to a safe level (whatever that is) ?
If having 0.5gigs free and nearly 2 gigs for cache is *really* causing the wb gui to stop responding then I will happily buy more ram, but I find it a bit strange.
I would have expecetd the cache to reduce in size as free got low and only get problems when the free and cache dropped to vrtually zero?
Thanks!