Monday, October 27, 2014

FreeBSD with multiple Serial Adapters acting as Access Console Server

I play a lot with network equipment like switches, routers and firewalls. It is very useful to have local serial access to consoles of such devices. When I say local, I mean remote access to local serial console. I can use some commercial Access Console Servers from companies like Avocent but these devices are usually very expensive and don't do anything else than linux box with multiple serial ports accessible remotely via ssh or telnet.

So my idea was to use my favorite unix-like system (FreeBSD) with multiple serial ports. For such appliances I usually use Soekris or Alix boards with FreeBSD on Flash. The question is how to have multiple serial (RS-232) ports. The simplest method nowadays is to use usb serial adapters. I know these usb serial converters has some issues but it is really the simplest peace of hardware to buy, plug and play.

When you use some of these USB converters you should see new devices. In my case I see in dmesg following devices:
uftdi0: on usbus1
uftdi1: on usbus1
uftdi2: on usbus1
uftdi3: on usbus1
To make serial console working you have to load uftdi module. uftdi -- USB support for serial adapters based on the FTDI family of USB serial adapter chips.

The easiest way is to load this module during boot. You just need to add to /boot/loader.conf following line
After next boot you will have following new devices in your /dev/ directory
 ... and you can use program cu to connect to particular serial console. For example
cu -l /dev/cuaU0 -s 9600
to connect to console with speed 9600 bauds.

Soekris NET4801-48 with USB reduction to 4xRS232

Friday, October 17, 2014

vCenter, Windows 2012 R2, .NET 3.5 issue

It is well know that vCenter Server 5.5 requires .NET Framework 3.5. It is quite easy to install it by Server Manager GUI or by following command: 
dism /online /enable-feature /featurename:NetFX3 /all /Source:d:\sources\sxs /LimitAccess
Command above assumes Windows 2012 DVD in drive d:
... but i had an issue with installation getting following error.
PS C:\Users\Administrator> dism /online /enable-feature /featurename:NetFX3 /all /Source:d:\sources\sxs /LimitAccess

Deployment Image Servicing and Management tool
Version: 6.3.9600.17031

Image Version: 6.3.9600.17031

Enabling feature(s)
[===========================66.4%======                    ]

Error: 0x800f081f

The source files could not be found.
Use the "Source" option to specify the location of the files that are required to restore the feature. For more informat
ion on specifying a source location, see

The DISM log file can be found at C:\Windows\Logs\DISM\dism.log
PS C:\Users\Administrator>

I discuss this issue with our Microsoft Specialist and he already knew the root cause and fix. The root cause was some bad Windows update. It is already fixed by Microsoft and if you didn't do update in bad time you should not experience this issue. However, when you hit this bug the only solution is to run following Microsoft fix.  

Some more information about this issue:


Monday, October 13, 2014

Fibre Channel NPV and NPIV

I'm often asked by customers and colleagues what is the difference between NPV and NPIV. I don't want to write information which are already well written and explain by someone else. So please read this Tony Bourke blog post which is IMHO very well written.

Just quick summary.

NPV is CISCO term doing the same thing like Brocade Access Gateway or DELL Force10 NPG (NPIV Proxy Mode). All these technologies put the Fibre Channel switch in to the mode where they don't have Fibre Channel Domain ID and therefore works like absolutelly transparent Fibre Channel multiplexer or intelligent pass-through if you wish. It significantly simplified SAN architectures and multivendor interoperability.

NPIV is the feature allowing Fibre Channel switch operates more FCIDs over single fibre channel switch port. So it effectively allows aggregation of more Fibre Channel Nodes (N-Port IDs) per single FC link.

Friday, October 10, 2014