With the advance of the FC-GS and FC-SW protocols the change, or more the enhancement, of being able to use Target Driven Zoning provided Brocade with the option to tinker a bit on the implementation of the functionality.
I get a huge amount of questions and nervous customers who tell me they see this counter increasing at an alarming rate and want to know if this is a problem or not.
The answer is yes and no. 🙂
That doesn’t help you much does it? Read on…..
FDMI stands for Fabric Device Management Interface and is such an enormously cool feature and unfortunately one of the least used. From an operational management perspective FDMI provides a wealth of information to the fabric regarding the attached devices. The thing that flabbergasted me is that almost no device (HBA/Array) has this turned on of even has the functionality embedded.
Switch fabric configurations over dark fibre, direct connect, links are not much different then connecting them when they sit next to each other. There is no physical interference which has an impact on protocol behavior.
As I’ve written before some features in FOS 7.3 and older have been superseded by new tools such as MAPS and FlowVision. On of those is also Advanced Performance Monitor which let you set up monitoring points in the fabric to identify traffic patterns. Continue reading
Storage networks have been used for disaster recovery and business continuity purposes for as long as fibre-channel existed. The moment arrays could communicate to other arrays over either short or long distances replication software has been developed and incorporated in firmware so that data could be copied to remote sites.
It is no secret that many vendors use open source software in their products and solutions. One of the most ubiquitous is Linux which is often the base of many of these products and used as core-OS because of it’s flexibility and freely available status without the need of keeping track of licenses (to some extent) and costs.
These OSS tools have different development back-grounds and are subject to policies of the person (or people/companies) who develop it. This obviously results in the fact that defects or bugs may result in security issues especially when it involves network related applications. Recently the bugs in OpenSSL and Apache have gain much traction as some of these are fairly significant and can result in access breaches or denial of service.
The piece of spinning Fe3O4 (ie rust) is by far the slowest piece of equipment in the IO stack. Heck, they didn’t invent SSD and Flash for nothing, right. To overcome the terrible latency, involved when a host system requests a block of data, there are numerous layers of software and hardware that try to reduce the impact of physical disk related drag.
One of the most important is using cache. Whether that is CPU L2/L3 cache, DRAM cache or some hardware buffering device in the host system or even huge caches in the storage subsystems. All these can, can will, be used by numerous layers of the IO stack as each cache-hit means it prevents fetching data from a disk. (As in intro into this post you might read one I’ve written over here which explains what happens where when a IO request reaches a disk.)
To many it has always been a mystery what happens when you connect fibre-channel switches to each other and all of a sudden magic happens and you can have an host “talk” to an array or an other device on an other switch. The same mystery however applies when this doesn’t work and you see “E-port segmented, port disabled”. In later FOS codes you may see some additional cryptic reasons like “ESC mismatch” but to many this is as gibberish as particle physics.
This post explains most of the important settings on an Brocade switch port destined to become an E-port in either a standalone master or in a slave role as part of a trunk. I’ll also highlight the importance of some settings when it comes to virtual channel initialization on both short and long distance settings as well as things seen on the wire when an ISL is segmented due to a fabric configuration problem. This post also touches on C/DWDM connectivity in relation to Brocade ISL’s.
As with all good stuff there are always people and companies that try to jump on the bandwagon and make some dollars by using cheap kit and sell it as “Original” or “Compatible” or “Vendor equivalent”. Don’t fall for this trap and simply buy Original Vendor Branded & Supported equipment. One example is FiberStore.