Solved

What is a Fibre Channel Disk within an EMC SAN?

Posted on 2010-09-08
7
607 Views
Last Modified: 2012-05-10

Hi

I'm confused as to what a Fibre Channel Disk is!

I understand that Fibre Channel Protocol (FCP) is a network technology similar to TCP/IP. Also, I understand that for storage, SATA or SCSI can be transported over FCP.

However, our CLARiiON SAN has two types of disks which it calls SATA and FC.

I think I understand SATA as SATA being carried over FCP.

However, is the FC disk SCSI being carried over FCP? Or is the FC disk some type of FC protocol for transferring data carried over FCP?

Finally, does FCP operate in a similar fashion to the TCP/IP stack i.e. are the SATA/SCSI command encapsulated within a FCP "packet"?

Thanks

John
0
Comment
Question by:TSC70
7 Comments
 
LVL 11

Expert Comment

by:Coast-IT
ID: 33627492
I hate to quote wiki, but in this case it's the best explanation ;

http://en.wikipedia.org/wiki/Fibre_Channel_electrical_interface
0
 

Expert Comment

by:edhorch
ID: 33627566
Think of Fiber Channel as just another disk interface like SCSI, IDE, SATA, etc..  Despite the name, FC can be used with either optical fiber or copper physical connections between the drive and the interface.  Most operating systems identify FC drives using the same notation as SCSI, i.e., {which controller, which interface, which target number, which LUN}, but in a SAN situation, physical drives don't matter--the drives a client sees are virtual and configured in the SAN, independently of the drives themselves.
0
 
LVL 47

Expert Comment

by:dlethe
ID: 33627597
A simple somewhat watered down, and purposely ambiguous enough to get point across w/o making you do a lot of reading from perspective of the EMC product is that FC & SATA represent 2 different types of disk drives that the EMC supports.  They have additional hardware to "convert" SATA physical interface so that it can plug into a FC port on their array.   Once this interposer is added (the hardware magic), the native ATA commands that a SATA disk uses are encapsulated within a SCSI command-set, which is then encapsulated within FC frames as you suspected.  (Again, not getting as deep as I could, but hopefully this is enough to get the 10,000 foot view)

This electronics makes the SATA disk appear as a FC device, so all of the wonderful EMC software can use it.  The downside is that SATA disks are slower and have less diagnostic capability. Mix and match as you desire.  SATA=cheap and slow,  FC=expensive and fast.  
0
Free Gift Card with Acronis Backup Purchase!

Backup any data in any location: local and remote systems, physical and virtual servers, private and public clouds, Macs and PCs, tablets and mobile devices, & more! For limited time only, buy any Acronis backup products and get a FREE Amazon/Best Buy gift card worth up to $200!

 

Author Comment

by:TSC70
ID: 33627663
Hi dlethe

That is very helpful!

What I still don't understand 100% is that does the FC disk still use/encapsulate the SCSI command set i.e. are they SCSI disks? Or is there an equivalent FC protocol for SCSI?

Thanks

John
0
 
LVL 47

Accepted Solution

by:
dlethe earned 500 total points
ID: 33627734
FC, SCSI, SAS drives all "speak" the SCSI command-set.   IDE/ATA/SATA disks speak the ATA command set.

Yes fibre channel is a flavor of SCSI. it is serial SCSI, the SCSI you are familiar with, that has 50/68/80 pins is parallel SCSI.  SAS disks use serial SCSI interfaces.  Don't confuse the interface type with the instruction set.  This is what throws people off.

P.S.  USB also speaks SCSI, and it is a serial interface.  And while I am at it, put a SATA disk on a SAS controller and it also speaks SCSI.   Most RAID controllers designed for ATA/SATA disks also present a SCSI device to the O/S.

0
 

Author Comment

by:TSC70
ID: 33627803
Hi dlethe

That makes alot of sense. Thanks. The separation of SCSI as a command set and its interfaces (parallel, serial, IP, FC) clarifies things immensely.

A final query - what would be a good resource to do a bit more reading on this?

Thanks

John
0
 
LVL 47

Expert Comment

by:dlethe
ID: 33628099
T13.org, t11.org, t10.org ...
Those are the tech sites that have ALL the specs.  I'm not up on any survey or introduction type material.  
0

Featured Post

New My Cloud Pro Series - organize everything!

With space to keep virtually everything, the My Cloud Pro Series offers your team the network storage to edit, save and share production files from anywhere with an internet connection. Compatible with both Mac and PC, you're able to protect your content regardless of OS.

Join & Write a Comment

We wanted to provide an in-depth explanation of the Ping Node offering clarifications on its function and usage. Incorrect Ping Node configuration and functionality can cause problems with HA clusters. The importance of this article is critical for …
We all have limited time to study long and complicated information about RAID theories, but you may be interested as to how RAID 5 works. We made it simple for you by providing the shortest and easiest explanation ever.   First we need to remind …
This video teaches viewers how to encrypt an external drive that requires a password to read and edit the drive. All tasks are done in Disk Utility. Plug in the external drive you wish to encrypt: Make sure all previous data on the drive has been …
This Micro Tutorial will teach you how to reformat your flash drive. Sometimes your flash drive may have issues carrying files so this will completely restore it to manufacturing settings. Make sure to backup all files before reformatting. This w…

758 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

13 Experts available now in Live!

Get 1:1 Help Now