On Fri, May 27, 2022 at 06:52:22PM -0700, Eric Wheeler wrote: > Adriano who started this thread (cc'ed) reported that setting > queue/write_cache to "write back" provides much higher latency on his NVMe > than "write through"; I tested a system here and found the same thing. > > [...] > > Is this expected? Once you do that, the block layer ignores all flushes and FUA bits, so yes it is going to be a lot faster. But also completely unsafe because it does not provide any data durability guarantees.