On Tue, 18 Sep 2018, Eric Sandeen wrote: > On 9/18/18 9:29 AM, Mikulas Patocka wrote: > > > On Tue, 18 Sep 2018, Eric Sandeen wrote: > > ... > > >> See also > >> https://www.intel.com/content/www/us/en/support/articles/000006392/memory-and-storage.html > >> > >> -Eric > > > > And does it really support native 512-byte writes? Or does it emulate > > 512-byte writes by doing read-modify-write? That needs to be benchmarked, > > the paper doesn't say that. > > Interesting from a manual tuning perspective, but not from a default > behavior perspective. > > I'm just pointing out that Intel does seem to give the user a choice about > the /advertised/ geometry for some of their SSDs. > > > Memory is expensive and reducing SSD sector size increases memory > > requirement on the SSD. I doubt that any SSD vendor would want to use > > 8-times more memory just to support 512-byte sectors natively. > > Marketing decisions aside, we just can't safely ignore what the device > tells us about these IO sizes. No one is forcing you to use 512-byte writes. You can use 4k writes on a device that advertises 512-byte sectors. ext4 uses 4k block size by default (and lets the user lower it if the user is tight on disk space and doesn't care about performance). Mikulas
