On Mon, May 11, 2020 at 03:42:44PM -0700, Phil Karn wrote: > On 5/11/20 14:13, Alberto Bursi wrote: > > > > Afaik drive-managed SMR drives (i.e. all drives that disguise > > themselves as non-SMR) are acting like a SSD, writing in empty "zones" > > first and then running garbage collection later to consolidate the > > data. TRIM is used for the same reasons SSDs also use it. > > This is the way they are working around the performance penalty of > > SMR, as it's the same limitation NAND flash also has (you can write > > only a full cell at a time). > > > > See here for example > > https://support-en.wd.com/app/answers/detail/a_id/25185 > > > > -Alberto > > Right, I understand that (some?) SMR drives support TRIM for the same > reason that SSDs do (well, a very similar reason). My question was > whether there'd be any reason for a NON-SMR drive to support TRIM, or if > TRIM support necessarily implies shingled recording. I didn't know > shingled recording was in any general purpose 2.5" spinning laptop > drives like mine, and there's no mention of SMR in the HGST manual. According to https://hddscan.com/blog/2020/hdd-wd-smr.html 2.5" SMR drives appeared in 2016. > Phil > > >
