24 Apr
2018
24 Apr
'18
3:03 p.m.
On 4/24/2018 5:37 AM, Michael Kjörling wrote:
I couldn't quite resist, so tried it out. Take this for what it is, an
anecdote.
To make it even worse in terms of trying to figure out what a disk will
do for (to) you in terms of performance...
A new caching scheme on a set of 10TB drives I bought a while ago - they
are HGST SAS drives.
They incorporated a set of cylinders spaced across the disk that are
"cache" cylinders. Wherever the heads are "right now", the closest
cache
cylinders will be used to write to. Once there's enough free time, it
will go back and read those cache cylinders, and put the blocks where
they are "supposed" to be.
http://www.tomsitpro.com/articles/hgst-ultrastar-c15k600-hdd,2-906-3.html
Those are not the drives I bought, but as far as I know, even their
near-line SAS products have this feature, called NVC Quick Cache
ak