Soft memory errors on SunFire will help you understand how soft errors occur and the meanings of a sticky error. Normally it indicates hardware replacement.
From the document:
Sticky means that the error still exists in memory even after the scrub
operation. These events should be investigated further to determine if some
hardware replacement is necessary since this is indicative of a hard failure.
If, during the handling of a CE event, the Solaris software cannot correct the flipped
data bit in memory, it will label the event Sticky instead of Persistent. This
disposition is fundamentally different in that it is not consistent with naturally
occurring events. Rather, it is an indication of a hard fault. Any components that
have been diagnosed with a hard fault should be replaced as soon as possible.
