- We're talking about virtualizing servers in a VMware ESX environment.
- We know that it is possible to have a connection between a virtual machine's comm port and the physical machine's comm port.
- In a virtual infrastructure, it is common to have a 8 to 1 ratio of virtual machines to physical machines.
- It is not possible to VMotion a VM while it is connected to a physical device on the host.
- Connecting a VM to a physical device is a large drain on the ESX box and that performance between the device and the VM will suffer because of it.
- Without using specialized hardware, there are commonly only 2 serial ports on a server. VMware ESX does not support much in the way of specialized hardware. If each of our virtual servers is using one serial port, there are not enough serial ports to go around.
The solution is quite simple. Thanks to the nice folks at Avocent, you can now connect your VMs to serial devices over the network and nobody's the wiser. Your applications will never know the difference... you'll still be able to VMotion your virtual computers, performance will not suffer and you'll have as many ports as your little heart desires.
With the ESP-4 MI
from Avocent, you can have your cake and eat it too. Basically you install software on your virtual machine, whether it is linux or windows (or whatever else they support), then configure the software to create a virtual comm port. This comm port looks and feels like a comm port as far as any application is concerned. You configure the software to connect the virtual comm port to one of the physical comm ports on this ESP-4 via the network. Plug your devices in and away you go.
They have these units with up to 16 comm ports, some with specialized features such as opto-isolated I/O, RS-422, RS-485, etc... You can read their site if you're interested in more details.
These units have a nice management software package and broad OS support... including: WinNT, Win2k, Win2k3, WinXP, Citrix, Linux, AIX, SCO, Unix & Solaris.
It seems like they have not caught on to the virtual market place as a niche market for their products... Yet!
I have not tested this product myself, so I cannot say from first hand experience that this is a good product, but the idea seems solid. The company's been around for a long time and seems like they will be for a long time to come. Hopefully I'll be able to test one of these myself and report back on how it worked.
I have an immediate need to do so as soon as this year's budget stuff gets approved. We have a time clock that runs off a serial connection. If we want to virtualize that server, our options are to replace the time clock with an ethernet-based one (approx $1,500) or get one of these devices (approx $300). Also, our Digital Cable TV Head-End is about to get a face lift. New middleware. This new middleware requires that we use a serial-based EAS (Emergency Alert System). If we wanted to virtualize this new middleware server, we'd be out of luck without a device like this. I hope it works as well as I think it might!
Buy.com has these at a pretty good price and they have a coupon out now that will save a little money if you opt to order one. This coupon expires 2/28/2006, so hurry if you're planning on getting one.$10 OFF $175 or more in ALL Stores at Buy.com! New Customers. Exp 2/28!
They have the 4 port model (ESP-4 MI) for $445.99 and the 2 port model (ESP-2 MI) for $281.99.