On 11/05/20 22:35, Phil Karn wrote:
On 5/10/20 22:06, Zygo Blaxell wrote:
The exceptions would be data extents that are explicitly deleted
(TRIM command), and it looks like a sequential overwrite at the _end_
of a zone (i.e. starting in the middle on a sector boundary and writing
Do these SMR drives generally support TRIM? What other spinning drives
support it?
I was surprised to recently discover a spinning drive that supports
TRIM. It's a HGST Z5K1 2.5" 5400 RPM 1TB OEM drive I pulled from an ASUS
laptop to replace with a SSD. TRIM support is verified by hdparm and by
running the fstrim command. There's nothing in the literature about this
being a hybrid drive.
Doesn't seem likely, but could it be shingled?
Phil
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
