SATA JBODs for backup-to-disk

[Folkert Rienstra]

Or in applications *with* RAID, even.

Sure they can be used in RAID applications. I use them for software RAID
all the time.

But there is nothing about them being JBOD that implies RAID.

Unless they *are* (external) RAID boxes.

That RAID people use JBOD's doesn't mean that the term JBOD implies RAID.

Nor that it doesn't.

 

[Folkert Rienstra]

I would not say this is "common usage". I've been using JBOD's for many
years and they have mostly had nothing to do with RAID.

If you get an enclosure full of drives it is either a RAID unit or a JBOD.

It can be both, depending on whether it has a controller or not.
Controller-less cabinets are often called JBOD cabinets.
One step further it can have a busconverter that converts the internal dri-
ves into the same number of drives with the external bus characteristics.
However, external RAID cabinets can have JBOD as one of the RAID
options and it can be a single volume (multidrive) JBOD as well as multiple
volume (one drive per) JBODs.

The only cross-over has been with the 3Ware RAID cards where if you
want to use a drive by itself, not part of a RAID set, then you specify
it as a JBOD drive.

Actually, that is how it is with almost every RAID controller.
And that is single drive JBOD as opposed to a multidrive JBOD.
Drives still get their own metadata. With some controllers you have to
choose single drive RAID0 or single drive RAID1 to not use stripe or
mirror (=JBOD).

JBOD has no "A" in it either.

Yes it has, in the same sense that there is no "R" in RAID0.
JBOD is an array of 'just a bunch of disks'.

They are not part of an array.

Yes they can be.

No one disk has anything to do with any of the other disks.

Yes they do, in a JBOD array.

That is the whole idea of JBOD's

Nope.
JBOD obviously has no meaning unless you group them in some fashion or
other. Group, array, get it?

(as far as I have ever heard).

Well, there's your problem then.

 

[Folkert Rienstra]

You're going to quote Wikipedia to me as an authorative source?

Well, I can show you a site just as authorative that says differently.

Now why don't you.

What is JBOD? - A Word Definition From the Webopedia Computer Dictionary
"Just a Bunch Of Disks Used to refer to hard disks that aren't
configured according to RAID -- a subsystem of disk drives that improves
performance and fault tolerance."

Authorative, huh? Bwahahah.

Still can be an array then, just not one that's "a subsystem of
disk drives that *improves performance and fault tolerance* ".

Try again, idjut.

 

[Folkert Rienstra]

It's very simple,

Ya think?

if you can see and control the disks individually in the OS, then they
are JBODs. If the OS just sees the volume and not the underlying
disks, then it's not JBOD.

Pity single volume-multiple drive JBOD shows up as a single disk.

There are two definitions for JBOD, one for a physical storage cabinet
and one for a logical array type definition, independent of where the
physical drives or the raid controller reside, internal or external.

 

[Folkert Rienstra]

I worked for a reseller of storage systems for years, and that is the
first time I've ever even heard of JBOD being described as another
term for concatenation.

Right, so obviously you do know better than you let us on to believe here.

To me there was never any confusion about the term, nor any
hint that the term was under confusion, until this discussion.

Except the one that you just created here, troll.

Read the discussion forums in the Wikipedia entry about that JBOD term.
It is being described as being completely wrong by most of the
discussees.

I will be editing that definition from Wikipedia in a few
days when I have some time. It's completely wrong.

Like they'll let you, windbag.

 

[Folkert Rienstra]

That Wikipedia entry is completely f*ked up, it's time to change it.

It's fine, keep away from it.