jgreco
Resident Grinch
- Joined
- May 29, 2011
- Messages
- 18,681
My understanding of that (based at least in part on looking at the code) was that it was an optimization primarily for databases where there was no dedicated SLOG device. In such a scenario, a large write being committed to the ZIL area of the pool is more or less similar in terms of performance to a large write just being written to update the data, so in that case it skips the ZIL. But it's kind of a complex optimization, and it looks like it'll still run larger sync writes through the ZIL as long as it is on a SLOG, so it gets hard to wrap your head around all the cases.