Newbie, whats a Director, and JBOD?

Hi,

I'm very new to the storage technology, and have been doing some
readings to understand the basics of fiber channel technology.

I'm stuck with these two basic terms: fiber channel director, and
JBOD, what are they? when do you use a director as opposed to a
switch?

Will appreciate if you could forward a link to any resource that could
help me.

thanks,

Ash

hello

I suggust you visit www.sanacademy.com and www.dothill.com
also www.snia.org has a storage dictionary.

A JBOD _ Just a bunch of disks
this is an external disk chassis (that means no RAId controller)
they can be in SCSI, FIBRE or IDE to SCSI/Fibre
Ususlly connected to a PCI Raid controller by can often be
just connected to a HBA

a Director is a lot more complicated and if you dont know when to use
a director over a switch you need to do some serious research.
a good guide line is the amount fibre connections you need.

However if your this new to storage it is unlikley that you will be
thrown into the world of directors - Currently switches come in
8/12/24/32 ports
directors start at 64




Ash wrote in message . ..
Hi,

I'm very new to the storage technology, and have been doing some
readings to understand the basics of fiber channel technology.

I'm stuck with these two basic terms: fiber channel director, and
JBOD, what are they? when do you use a director as opposed to a
switch?

Will appreciate if you could forward a link to any resource that could
help me.

thanks,

Ash

AlanY wrote:
a Director is a lot more complicated and if you dont know when to use
a director over a switch you need to do some serious research.
a good guide line is the amount fibre connections you need.

However if your this new to storage it is unlikley that you will be
thrown into the world of directors - Currently switches come in
8/12/24/32 ports
directors start at 64

Wouldn't a good rule of thumb be that if you need to connect edge devices such
as JBODs, tapes or hosts, you need an FC switch. If you need to connect switches
to each other to create a fibre backbone or a large fabric, you'll need a director ?
Usually directors don't support anything but point-to-point because they are
designed as core fabric switches connecting to other switches, so devices like
JBODs (which traditionally require arbitrated loop) can't even be connected to
directors.

Arne

On Wed, 29 Oct 2003 08:24:08 -0700, Arne Joris wrote:

AlanY wrote:
Wouldn't a good rule of thumb be that if you need to connect edge devices such
as JBODs, tapes or hosts, you need an FC switch. If you need to connect switches
to each other to create a fibre backbone or a large fabric, you'll need a director ?
Usually directors don't support anything but point-to-point because they are
designed as core fabric switches connecting to other switches, so devices like
JBODs (which traditionally require arbitrated loop) can't even be connected to
directors.

Arne

In general you are correct. Directors are also called edge switches,
usually packed with routing capabilities that will route FC traffic to an
IP network (or to and from any other form transportation) to another
director switch that does the reverse. This way you aren't confined to a
single technology. I've noticed the industry moving away from using the
term "director".

Note to the OP, many folks will refer to any disk chasis as a JBOD, namely
those that have been around storage for a while. Alan gave you the
correct definition of a JBOD, but don't be caught off gaurd if someone
refers to something else as a JBOD even though they are inherantly
incorrect.

- Jake