After many complaints from the developer community about poor networking performance on Yosemite, the latest beta of OS X 10.10.4 has dropped discoveryd in favor of the old process used by previous versions of the Mac operating system. This should address many of the network stability issues introduced with Yosemite and its new networking stack.
The discoveryd process has been subject to much criticism in recent months as it causes users to regularly drop WiFi access and causes network shares to list many times over, due to bugs. Many developers, such as Craig Hockenberry, have complained about the buggy software and workarounds have been found to include substituting the older system (called mDNSResponder) back into Yosemite.
discoveryd would cause random crashes, duplicate names on the network and many other WiFi-relate bugs. In the latest beta, Apple appears to have applied the same fix as the enthusiasts by axing discoveryd completely.
Looking at Activity Monitor on OS X 10.10.4 seed 4, discoveryd is no longer loaded by the system — instead relying on mDNSResponder. The ‘new’ process is really the one Apple used to use pre-Yosemite and did not have these problems.
It is still unclear why the change in the networking stack was ever made given that the old process worked so well and the new process had so many issues. There has been some speculation that the new stack is related to AirDrop and Handoff functionality although testing showed that these features still worked when the system was reverted back to the old process.
Regardless, it will please many to see that Apple has finally addressed these complaints, even if it embarrassingly involves going back to the old system rather than fixing the new code. OS X 10.10.4 will be released to the public in the coming months.
Apple is focusing on performance and stability for iOS 9 and OS X 10.11, so it will be interesting to see whether discoveryd makes a comeback in Apple’s next-generation operating system.