On Tue, May 09, 2017 at 11:02:46AM -0400, Dan Ritter wrote: > On Tue, May 09, 2017 at 03:35:04PM +0200, David Guyot wrote: > > Hello, there. > > > > I recently loaned a server with NVMe SSD and saw, during my research on > > the relevance of the discard mount option for them, that its use is > > discouraged for NVMe SSDs. Why? Does NVMe SSDs not need trimming? Is it > > integrated in the NVMe driver for Linux? > > Intel, among other NVMe SSD manufacturers, recommends using > fstrim periodically rather than enabling continuous trimming > with the discard option. > > They don't specifically state why, but I will hazard a guess > that performance is impacted during a trim, and doing so for > a short period once a day or once a week is more useful than > decreasing performance all the time.
Evidence from Ted Ts'o: https://forums.freebsd.org/threads/56951/#post-328912 which boils down to: A) yes, there's a performance impact B) the systems which listen to TRIM commands do better on large allocations than on small, so batching them up with fstrim called by cron is preferred. -dsr-
