[TUHS] /dev/drum

[Bakul Shah]

On Mon, 23 Apr 2018 22:59:19 -0600 Warner Losh <imp at bsdimp.com> wrote:
> >         ...
> >         Not_Zoned       # Zone Mode <<== this seems wrong.
> >
> 
> That's right. This is for BIO_ZONE stuff, which has to do with host managed
> and host aware SMR drive zones. That's different than the zones you are
> talking about.

Ah. Thanks! Does host management of SMR zones provide better
throughput for sequential writes? Enough to make it worht it?
[I guess this may be something you guys may care about?]
Haven't had a chance to work on storage stuff for ages.  [Last
I played with Ceph was 5 years ago and at a higher level than
disks.]

> Yes. This matches our experience where we get 1.5x better on the low LBAs
> than the high LBAs. We're looking to 'short stroke' the drive to the first
> part of it to get better performance... Toss a filesystem on top of it, and
> have a more random workload and it's down to about 30% better than using
> the whole drive....

Is the tradeoff worth it? Now you have choices like Sata vs
SAS vs SDD vs PCIe....

We've come a long way from /dev/drum :-)