
What Is Zoned Storage and the Zoned Storage Initiative? - ingve
https://blog.westerndigital.com/what-is-zoned-storage-initiative/
======
keeperofdakeys
For anyone wondering "why", this linked article in the source gives some
background, [https://blog.westerndigital.com/storage-architectures-
zettab...](https://blog.westerndigital.com/storage-architectures-zettabyte-
age/)

So instead of SMR harddrives and SSDs doing extra work to hide their
deficiencies, they're pushing this up into the filesystem. In return you get
slightly more storage and slightly faster IO. Perhaps not useful on a desktop,
but very useful when dealing with thousands of storage devices in a data
centre.

In terms of how it would be exposed to users, this feels very well fitted with
object storage. Unlike file-based storage, each object can only be read or
replaced. So any partial write relies on the program to read the whole object,
then write the updated object.

~~~
bonzini
It also fits well log-structured and copy-on-write filesystems.

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paol
Yes! That was my first thought. The way SMR and SSDs work actually aligns
pretty well with log structured filesystems.

In this case, the firmware translation layer is only getting in the way.

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h2odragon
" In SMR, unlike conventional recording, tracks are written in an overlapping
manner. ... once the tracks are overlapped, they cannot be written
independently. there are disadvantages for device-side localized management.
... Managing the complexity on the host side is almost a requirement"

also links: [https://www.zonedstorage.io/](https://www.zonedstorage.io/) for
further information.

Sounds good to me; exposure of the actual mechanisms instead of outdated
abstractions makes sense. I'd even argue for open access to motor controllers
and raw signal buffers but apparently I'm insane.

~~~
josefbacik
Host managed also means messing with the file system, and the patch set for
btrfs is not small. Plus you have to disable a bunch of features (like
preallocation since you can’t move the write pointer backwards) which is going
to surprise people in unfun ways. These drives are useless for general
purpose. If you are going to use them as expensive tape then by all means, but
otherwise I have serious doubts about their usefulnes.

Edit: I’m talking specifically about the SMR side. The general zoned stuff is
interesting, but when you start putting restrictions on how you can write to
certain zones you wind up with a lot of weirdness that application developers
are going to be surprised by.

~~~
rzzzt
Drive-managed SMR looks OK to me for general use, although I don't have hands-
on experience with it. They also have a non-shingled region that can accept
random I/O at higher speeds, and the drive deals with moving data to a linear-
only region once it fills up, or at garbage collection time.

It's very much like the QLC drives where a portion is treated as SLC/MLC.

~~~
loeg
It's like the QLC drives with SLC/MLC cache (e.g., Intel 660p) except the
performance cliff is far, far worse (and obviously the "fast" mode is far
worse as well).

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tw04
Candidly, the manufacturers haven't shown enough of a price savings to make
these drives worthwhile. As others have mentioned, there's a fairly
significant cost in development to using these drives efficiently. The only
way that makes sense is if there's a significant discount over non-SMR drives.
Nice blog post WD, but you're going to have to drop the price to about half of
what it currently is for these to make even a little bit of sense

~~~
mbjorling
Half of the world bits from HDDs are estimated to be on SMR in 2023 - the
gains are significant when deploying at scale.

For SSDs, it gets even more fun as zones aligns with the characteristics of
the media and you get this effect of significant increase in capacity (20%
with a 28% OP drive), order of magnitude reduction in dram, and eliminates
device side garbage collection on the drive (commonly between >1-5), which
improves the QoS considerably.

Additionally, one can now run the drives at 100% capacity utilization -
conventional drives becomes slower due to increasing device write
amplification.

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loeg
Zoned SMR storage has almost no use case outside of tape replacement.

The same drives configured in 100% random I/O mode lose a handful percent
capacity and the tradeoff for SMR zones is awful: rewrite your entire
filesystem stack (thousands of labor hours) _and_ expect awful performance.
For most businesses this is not an obvious win.

Meanwhile, big cheap dense SSDs get bigger, cheaper, and denser every day. You
don't have to rototill your filesystem to use them effectively. So I don't see
a lot of sense in investing in zoned filesystem support when archive tier
bottom-dollar storage can just use the unzoned, marginally smaller spinning
rust today, and switch to the unzoned, super lower write endurance flash media
tomorrow.

~~~
klysm
SMR does have a use case outside of tape replacement. It has higher density.
Take a look at DropBox MagicPocket - they designed their entire storage system
around SMR technology

~~~
loeg
It has _marginally_ higher density; I didn't forget this benefit. The tradeoff
is something like 5% more space vs much worse performance and many man-years
rewriting filesystems.

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cellular
I want write once storage. For photo backup. No virus or user error can ever
delete my photos.

~~~
loeg
There's always optical media or SD cards with physical write-protect toggles.
(If you leave the optical media in the writer, though, conceivably an absurdly
specific virus could cause the device to burn out existing contents.)

~~~
throwaway2048
The read/write switch on SD cards is 100% up to the reader device to honor or
ignore (seriously)

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m3kw9
What’s the difference between this and RAID?

~~~
m3kw9
Like RAID-0 specially

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sverhagen
On my Firefox Android this link goes into what seems infinite redirects. Um,
thanks?

~~~
kbenson
Works fine on Firefox for android for me

I did just experience Firefox opening infinite tabs when I opened a PDF last
week though, but I tracked that down to a problem I introduced, where I told
the OS to open PDFs in Firefox, and Firefox was still set to defer to the OS
for PDF handling. Could there be something similar going on here?

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StillBored
I seriously question the value of having this bloat up the kernel and general
purpose filesystems. Tapes work just fine with userspace support and there
isn't any reason for not having custom FUSE's for this as well.

Put another way, everyone suffers with code bloat and extra complexity for the
tiny percentage of users (which are large, and can manage their own systems)
this supports.

Edit:

The SMR drives should just support the SCSI streaming command set and be done
with it. That way nothing really needs to change anywhere but in the drive
firmware.

