Category Archives: Storage Networking

FCIP configuration, pitfalls and troubleshooting

Brocade Config Guide Troubleshooting No Comments

FCIP has been around for quite a while. The fine engineers of CNT/McData/Brocade/Rhapsody/Vixel (you name them) saw early one that a method was needed to overcome the, back then,  distance limitation of around 10KM. This was not due to a limitation in the FC protocol itself but more due to the fact the hardware back in the early 2000’s was not up to scratch to push FC frames over longer distances. Another drawback is that FC by nature is not routable. (Not taking into account the FC-IFR which came later and was developed between 2004 and 2008). That, by definition, makes it difficult to be adopted into existing infrastructures where no native FC extenders or other equipment like DWDM/CWDM was available to bridge the distance between two native FC pieces of equipment.

Contrary to popular belief the FCIP protocol was not developed under the T11 ANSI (now INCITS) umbrella but it was actually the IETF who took on this task. The standard is published under RFC-3821.

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6 – Non Standard configuration options

Config Guide No Comments

Features and licenses

Ever seen these?

License Envelope
License Envelope

If not you might just have thrown away one of the most expensive pieces of you purchase. This is the envelope that contains the transaction key which allows you to generate the license for the specific feature you bought. If you have discarded it I must say that is not really smart. It’s like throwing away the car-keys after you bought a brand new vehicle.

DO NOT THROW AWAY THIS ENVELOPE

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4 – Standards in operation

Config Guide No Comments

Consistency is one of the most important things in a computing environment. There are abundant examples where configuration inconsistencies have led to disastrous events leading up to dropped databases, setting up disk-mirrors in the wrong direction (ie overwriting a perfectly good partition with an empty one), operational mistakes due to wrong or unclear naming conventions and you name them. Anywhere where people work mistakes will be made so in order to try and prevent these kind of mistakes strict standards in operations needs to be followed. In the majority of businesses around the world some sort of framework for processes and changes is followed in the likes of ITIL or any of the alternatives.

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3 – Reference architecture

Config Guide No Comments

In this series of post I will start with a simplified SAN architecture based upon a dual-fabric edge-core-edge design. (Remember this might not be a good design as I described here but for the purpose of this guide it will suffice.) As we go along with other topics we’ll extend it as needed. The top switch is SW01, the core switch is SW02 and the bottom switch is SW03. This is valid for both fabrics.

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2 – Creating the management landscape

Config Guide No Comments

The first thing to think of when creating a Brocade storage network has nothing to do with a switch configuration at all. Its about the surrounding management landscape. There are numerous management software options available from a multitude of vendors including Brocade with Network Advisor. If you have purchased BNA then congratulations, you have a solid toolkit in your hands to take care of nearly everything you need to manage, maintain and troubleshoot the SAN. Despite this there are more things to take into account.

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RFE for Brocade FOS

Brocade 5 Comments

There is already a fair chunk of functionality in FOS but, being a support-engineer, you always come up with features and functions that will improve storage fabrics.

Being on a Ficon course last week and meeting some Brocade friends I requested them to add the following to the (most likely) long RFE (Request for Enhancement) list.

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Queue-depth

Config Guide General Info Troubleshooting No Comments

I recently was involved in a discussion around QD settings and vendor comparisons. It almost got to a point where the QD capabilities were inherently linked to the quality and capabilities of the arrays. Total and absolute nonsense of course. Let me make one thing clear “QUEUING IS BAD“. In the general sense that is. Nobody want to wait in line nor does an application.

Whenever an application is requesting data or is writing results of a certain process it will go down the I/O-stack. In the storage world there are multiple locations where such a data portion can get queued.When looking at the specifics from a host level the queue-depth is set on two levels.

(p.s. I use the terms device, port, array interchangeably but they all refer to the device receiving commands from hosts.)

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Signal quality and link stability

Brocade Config Guide Fibre Channel Storage Networking Troubleshooting 2 Comments

I really think I should stop with fillword discussions but here is one more. What happens even if you have set the correct fillword, have made sure all hardware is in tip-top shape and still the encoding errors fly around like a swarm of hornets. Then the problem of ISI might be more problematic.

The main issue still is that the receiving side is unable to distinguish between a 0 and 1. The so called eye-pattern is too narrow or too distorted in such a way the receiver is just seeing gibberish.

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