This is my first time posting in the forums, but I'm a long time reader of all the awesome articles on the site. While my forte is generally with ASA's and not UC500 series devices, I've run into a bit of a problem and Cisco TAC's solution seems like a cop out to me.
Basically, our UC500 has been crashed and we've tried changing configurations and upgrading the IOS image to no avail (although the error messages have changed a bit)
Below is the bug we're hitting. Were the errors point to either malloc failures due to not enough memory, and now it shows
CFORKMEM: Process creation of DNS Resolver failed (no memory). -Process= "Appfw IM DNS Resolver", ipl= 0, pid= 323
-Process= "Appfw IM DNS Resolver", ipl= 0, pid= 323
7130: Alternate Pool: None Free: 0 Cause: No Alternate pool
7129: Pool: Exception Free: 5704 Cause: Not enough free memory
While I've worked with the UC500 series, I haven't seen this issue before.
Despite the problems you've been experiencing, why don't you try downgrading to a earlier IOS image? Obviously the newer IOS releases require more memory and Flash, so you'll be forced upgrading that as well.
My suggestion is to try an earlier IOS that can run on your system's specs and see how that goes.
Sadly, the issue has been present on the M5, M6, and M7 images. They even had to create the M7 image specifically for our issue as its not available on the 520 platform. While the error message has changed slightly each time, this random crashing occurs. At this point the IOS Architecture team is trying to wipe their hands of the issue and blame it on not having enough DRAM, yet we only have about 35 users who make phone calls, and its not really heavy volume like a call center or anything.