Zoned Commands ZBC/ZAC, Shingled SMR drives, ZFS

[grarpamp]

The only 8T SATA options are:
8T for $675 ($84.38/T) 0F23267, 7.4W max (8k q1)
8T for $270 ($33.75/T) ST8000AS0002, 8.66W max (rand read)
For TB/$ or TB/RU there is no comparison, particularly for "archive" uses.
Going further:
6T for $250 ($41.67/T)
5T for $200 ($40.00/T)
4T for $140 ($35.00/T)
3T for $100 ($33.33/T)
go any smaller and the dollar, RU, and watt all fail to yield.
For other comparison:
SSD:
1T SSD $350 ($350.00/T)
Tape (excl drives and changers):
10T 3592JD $410 ($41.00/T)
2.5T LTO6 $23 ($17.20/T)
1.5T LTO5 $23 ($15.33/T)

The DM drive seems priced reasonably given 8T is largest drive on
market.

Prices on same density always go down, storage density always goes
up with a new price attached. SMR is the first real example of a
"feature" drive.

Want to guess where the 8T and 10T HA (performance mitigatable)
drives will price out?

usb-to-sata bridge not working...
There are stories both ways, none of them really trustable.
Doesn't matter now that the second batch of native SATA drives is
out.

The StorageReview tests were made with the drives in a NAS box.
The tests have obvious caveats depending on your usage. A generic
raid-1 rebuild is theory equivalent to a whole disk sequential dd.
The drive spec says you will see avg 150MB/s (~15hr) for that. SR's
NAS is obviously not doing a generic raid-1 rebuild there.

The tech path is "drive managed" --> "host managed" --> "host aware",
better performance mitigation on the right.

Developers can get DM and HA drives from Seagate.

My posts from Feb 26th and Mar 2nd have bunch of info links.
In the links find statements like these:

"ZAC and ZBC command sets cover both Host Aware (HA) and Host Managed
(HM) devices. SMR drives are expected to saturate the HDD market
over the coming years. Without this modification (ZBC command
support), HM will NOT work with traditional filesystems. With this
modification, HA will demonstrate performance and determinism --
as found in non-SMR drives -- in traditional & new applications."

"Seagate manufactures and supports SMR Drive Managed (DM) and SMR
Host Aware (HA) drives. Seagate does not currently manufacture SMR
Host Managed (HM) drives. Seagate has 2 drives shipping that are
SMR-DM. Seagate's new 8TB Archive HDD v2 drive is SMR-HA."

Another link:

http://events.linuxfoundation.org/events/vault
http://events.linuxfoundation.org/sites/events/files/slides/SMR%20in%20Linux%20Systems%20-%20Vault.pdf

Bottom line is that SMR and related tech is here to stay as the
next step in bulk storage and cannot be ignored.


http://ceph.com/
http://www.mkomo.com/cost-per-gigabyte-update