Many Conserver instances were started as an experiment. It was something to add to an existing console server deployment. It's usually installed on a seldom-used machine, probably older hardware, and maybe without support. But, it was certainly "enough to do the job, for now."
Once it was working, a few other folks started to use it. Then you offered to add more ports into the config for other system and network administrators. Soon, you've pulled in most of the original console server ports in the shop, and you're buying more console servers, and you're starting to look for more RAM and bigger hard drives. You're wondering if you are backing this system up, since the logs have become useful data. Then, one day, some data retention policy comes along, and you realize your console data just became Vital Records, and needs to be protected. It's time to think about an upgrade, and a service contract, and a way to write directly to archival media.
Why didn't you think about those things sooner? That's the topic for today's blog. What started as a demonstration just became critical infrastructure at one site I support. Here's what we are considering as we are looking for making this Conserver deployment a "Production Service".
Supported Hardware. Rather than a hand-me-down or a "Frankenstein machine", consider getting newer hardware. This will give you a longer product life (read that as "you can get tech support and replacement parts from the vendor" for 3-4 years), and you should consider the support contract, since this will likely become Critical Infrastructure if it hasn't already.
If you are trying to do this "on the cheap", you could try using a hand-me-down machine. Make sure you get a spare chassis (with power supply and motherboard), and and many drives and RAM! Remember, older drives and RAM get to be more expensive when they are no longer the new stuff! You'll also need to be able to service your own gear, on your own time.
Redundant Power Supplies. Unless your data center has fancy power distribution units that source two circuits to a since power cable, you should consider using a chassis that has dual power supplies. Make sure that the chassis can run fine (fully configured) on just one power supply! You should make sure that you are sourcing the power supplies from two different circuits. Also, find out if the power supplies have to be on the same PHASE of power, and find out BEFORE you plug them in. (Have I mentioned the value of a support contract for your hardware?)
I need RAM. Lots and lots of RAM. But how much is "lots". This depends on the number of consoles you plan to support, including your "someday" scenarios. Remember that Conserver starts with it's own process, and then spawns children for (generally) every 16 ports. Your OS will want some. And any other tools and scripts will need some. (If you are going to be editing large log files, searching large data sets, or processing many large log files, you're going to want a LOT of RAM, so that you avoid swapping memory to the hard drives.) Don't skimp on RAM.
Dedicated Log Data Drive(s). You don't want your logs on the same drive a your main OS. (If your console logs fill the disk over a holiday weekend, and your system can't write it's own system logs, your Monday morning is going to be a LONG morning!) How much space do you need? This is the hardest thing to estimate, since it really depends on how much you use your consoles. But, here is a good ballpark to start - estimate 20 MBytes for every console you plan to support, plus 1-2 GBytes as a buffer for when some logs start filling up faster than you expected.
Since Conserver can auto-rotate the logfiles when they reach a certain size, you want to consider how large a file you can open with the editing tools you want to use. I rotate my logs between 10-20 MB, and I use grep and PERL to find things. But if you use other tools that can't open files larger than, say, 5 MB, then you should adjust your log rotation size accordingly.
Use RAID to help protect your data. Even basic mirroring of your log drive will help protect the data set (your vital log files). If you are capturing a lot of very busy log files, you might want to consider striping the data. You may also want to consider hardware RAID support. (This can save you system some CPU overhead, but it also adds some hardware complication. Still, many sites are successfully using hardware RAID. If this is your first attempt to use hardware RAID, you should consider getting the hardware support contract for your machine.)
Consider using a RAID pair to protect your OS, scripts and tools as well! Many newer machines can host five 2.5-inch drives in a 1-Rack-Unit chassis. That gives you a pair for the OS, and a pair for log data.
Backing up your critical log files to archival media. CD media is cheap, but so is DVD media. (Heck, DVD drives are cheap, too!) You can get 5+ GBytes on a single-layer DVD, and must laptops and other workstations can read them. It's an ideal media for the day when the auditor comes and asks you to produce the log files for certain machines across a range of dates.
Remember, too, that most log data is going to be ASCII data. It's VERY compressible, and you can use PERL and cron jobs to compress the latest newly-rotated log files to a gzip version. This will let you store more log data longer, and lets you delete some of the older non-zipped versions. (Compressing the log files means you are going to be backing up the compressed logs, so you can store more of them on the DVD media...this means some savings in the number of discs you need to write over time.)
So, what would I recommend? Let me start by giving you the information that I'm using to base the decision, and then I'll tell you.
Given:
650 console ports today, could grow to 1024
(20 MB x 1,024 = 20 GB of drive, plus overhead, 25 GB minimum)
I want to store large amounts of compressed log files.
(3 yr retention needs for some files, 60 GB minimum)
1024 consoles means 65 processes, minimum, but more if my processes are really busy due to verbose logging. Could be 128+ Conserver processes later.
I want to run Splunk for log checking (RAM and drive implications.)
I also need drive space for backup, and log report manipulation.
What I'm proposing;
Dell 2950, with two 1.8 GHz Quad-core processors (Energy Smart)
Pick your OS (I'll pick Suse Linux, 3 yr license for the OS support)
8 GB of RAM (four 2 GB Dual Ranked DIMMs, Energy Smart)
Hardware RAID
76 GB, 15k-RPM drive threesome for the OS
146 GB, 10k-RPM drive threesome for the logs
Dual PS
This gives me a pair of drives for the OS, plus an on-site warm-spare, plus a pair for the logs with a warm spare. The drives are hot-swappable, so if I have a failed drive that RAID cannot recover, I'll yank the failed drive and swap in the warm spare, then let RAID rebuild it, and then I'll call Dell support for a next-day replacement, for the next three years. If I were really worried about hardware failure, I might opt for the 4-hour on-site contract.
Total cost comes in at $8.5k(US) today, from Dell, though the price may be better through other channels. (That works out to about $2,900 per year, or about $240 per month, to support 1,000 vital ports in the shop.)
Can you get by for less? Certainly. But, what is the cost to you if you lose log files you need to be retaining? What will the business impact be if the server is down for a day or more, and your administrators have to scramble to manage their servers and network gear 'the old fashioned way'? The cost isn't too bad, for Critical Infrastructure, now that it's proven itself to be useful and reliable. Shouldn't you put it on reliable hardware as well?
-Z-
20070714
Making progress, leaving footprints.
It's a bit depressing to see that I'm down to about one blog per month. At least I'm making a bit of effort hre, as well as making progress on the other projects that compete for my time.
As I've changed jobs, I appreciate the 'Oral History Project' that most companies use to store and share knowledge about network infrastructure, legacy reasons for doing things, even network architecture. But, I only like them a little, mainly because they aren't a stable source. People leave companies, or even just transfer to other departments. Stories change with time, and details tend to degrade very rapidly. I like documents better. (That's one large reason I make my web pages, and keep this blog.)
I learned a long time ago, from two examples, that the time it takes to make some basic documentation is largely paid ack when you use the documentation 3-4 times. Whether it's time saved when you refer to it yourself at a later date, or whether it's time saved when you give the document to someone else, and they can do a task, without you needing to give them the information via storytelling and sitting with them while they do the task. (I won't put the example stories in this article, to save space. Maybe I'll post them in a separate article, if there is some demand for them.)
When I'm debugging a problem, I keep notes, usually in a 'notepad' or 'teach text' file. (Save the file with a useful name, and save it often during the project!) If I'm working on a device configuration, I keep a diary of the changes I made, in case I need to revert anything. I also paste in any error messages I get during the process.
BUT, here's the message for this blog... During the process, I make notes about some of the useful options for some of the commands I'm using. (I needed to look through the syntax for this effort, and I learned something...so I save it for a future effort!) When I'm done, and I've figured out the proper sequence of commands, I now have a basic document that shows me the correct steps, and a few added notes for related commands. If I take an extra 30-60 mintes, I can add some comments for the next time... things to be aware of, pitfalls to avoid, information to gather before you start, how long it might take... these all get into the document.
At the end of the effort, I now save a copy of the file in a "Clues" directory. This is my 'canonical' place for the most current version of my clues, for anything I've worked on. I've written my stories down, and everyone on the team knows where to look for them if they need to work on a project. If I'm unavailable, my team will still have access to useful knowledge on an array of tasks. (And, if it's easy to hand off a project, it's more likely I'll be able to hand it off and do something more interesting the next time.)
Make a clues repository, start gathering simple process docs, and get the other folks in your department to share in filling the repository.
-Z-
As I've changed jobs, I appreciate the 'Oral History Project' that most companies use to store and share knowledge about network infrastructure, legacy reasons for doing things, even network architecture. But, I only like them a little, mainly because they aren't a stable source. People leave companies, or even just transfer to other departments. Stories change with time, and details tend to degrade very rapidly. I like documents better. (That's one large reason I make my web pages, and keep this blog.)
I learned a long time ago, from two examples, that the time it takes to make some basic documentation is largely paid ack when you use the documentation 3-4 times. Whether it's time saved when you refer to it yourself at a later date, or whether it's time saved when you give the document to someone else, and they can do a task, without you needing to give them the information via storytelling and sitting with them while they do the task. (I won't put the example stories in this article, to save space. Maybe I'll post them in a separate article, if there is some demand for them.)
When I'm debugging a problem, I keep notes, usually in a 'notepad' or 'teach text' file. (Save the file with a useful name, and save it often during the project!) If I'm working on a device configuration, I keep a diary of the changes I made, in case I need to revert anything. I also paste in any error messages I get during the process.
BUT, here's the message for this blog... During the process, I make notes about some of the useful options for some of the commands I'm using. (I needed to look through the syntax for this effort, and I learned something...so I save it for a future effort!) When I'm done, and I've figured out the proper sequence of commands, I now have a basic document that shows me the correct steps, and a few added notes for related commands. If I take an extra 30-60 mintes, I can add some comments for the next time... things to be aware of, pitfalls to avoid, information to gather before you start, how long it might take... these all get into the document.
At the end of the effort, I now save a copy of the file in a "Clues" directory. This is my 'canonical' place for the most current version of my clues, for anything I've worked on. I've written my stories down, and everyone on the team knows where to look for them if they need to work on a project. If I'm unavailable, my team will still have access to useful knowledge on an array of tasks. (And, if it's easy to hand off a project, it's more likely I'll be able to hand it off and do something more interesting the next time.)
Make a clues repository, start gathering simple process docs, and get the other folks in your department to share in filling the repository.
-Z-
20070602
The Emergency Kit
I've put together a small kit, which can give me quick access to the serial consoles of various machines, for those little emergency trips to the colocation facility, or a customer site. It's been so successful and handy that colleagues are borrowing it for small cluster jumpstarts, and even for a Disaster Recovery exercise. So, I'd also describe it here.
The gist is, I started with a small 8-port console server, so I could use my laptop, a pre-configured telnet client, a crossover-Ethernet cable, and a handful of adapters to connect to various devices. I found that I often needed to be connected to the machine's network as well, so I added a small hub to the kit, as well as a small power outlet strip to my laptop bag.
I picked the Cyclades TS-800 8-port console server because it was small, was BREAK-safe, and ran from a 'wall wart' (power pack). I really wanted one that could run on 12-volts DC, so I could run the kit on car battery power, but couldn't find one. My laptop can also run from 12-volts DC (which could be handy in an emergency). Sadly, the TS-800 units are no longer sold by Avocent, but there are still a variety of small console servers on the market.
The small console server fit in the large pocket of my laptop bag, but limited how many cables I could carry, along with all the adapters. I finally fell to using a small, extra bag for the console bits.
I added a small 10-Mbps hub initially, so I could also do some packet sniffing, since most small switches don't have the ability to 'span' or 'mirror' ports. But, that bottleneck also throttled network access to the attached device, and I wasn't doing so much packet sniffing, so I 'traded up' to a Allied Telesyn AT-FS708LE 8-port 10/100 Mbps switch. This is a 12-volt DC device. It's small, lightweight, sturdy, and still available cheaply.
The kit now includes the switch, the console server, two crossover-Ethernet cables (1'- and 5'-long), an assortment of lengths of regular 8-wire CAT-5 cables, and an assortment of 24 Cyclades serial adapters. I also have a few 1'-long Cyclades null-modem (DCE-to-DTE crossed RJ-45 cables, and a few CAT-5e-rated female RF45 couplers. Add in the wall warts, and the kit lives in a 6-quart Sterilite plastic container about the size of a shoebox. Easy for security folks to see what is inside, but you don't want to put this in the belly of an airplane.
The Console Server is really the key to this kit, so here's what I've done to make it work;
First, configured the device as a console server, then copied the config file so I have an on-board copy, in case someone feels the need to change settings while they borrow it.
cp /etc/portslave/pslave.conf /etc/portslave/pslave.bkup
Make sure the backup config is saved into the unit's NVRAM. On the Cyclades, this means adding the file into /etc/config_files. (This is one reason I strip most of the comments out of my console server config files, since I'm basically saving two copies of the configuration file.) Now, if someone needs to change the config file, it's quick and easy to get back on the console, and copy the config back over the pslave.conf file, then 'saveconf' and reboot.
I also add an entry for my laptop into the /etc/hosts file on the console server, to reduce delays when making your reverse-TCP connections to the console server.
I had originally assigned different port speeds (19.2k, 38.8, 57.6, and 115.2) to ports 5 through 8, to make it quick and easy to access a high-speed port. But, I found that most ports are STILL at 9.6kbps as a default, and sometimes I needed more than 4 ports. In those cases when I needed a higher speed, I often needed more than one port at the higher speed at the same time. Since I found myself making many configuration changes I decided to revert the base configuration to 9.6k all 'round, but that's just explaining my reasons. You may want to do it your own way, and that's up to you.
I also pointed all the "extra" services (Radius server, syslog, etc) that the console server might want to use to the laptop IP address. I already use a small but of RFC-1918 address space, to reduce the chances of a conflict with the network that I may attach to. Pointing just to my laptop reduces the chance of the TS tripping any Intrusion Detection System (IDS) that might be watching the network. (I don't use the Syslog much anymore, but if I want to try it, that's one less part I need to configure.)
The current laptop is a PC, using PuTTY as the client tool. This lets me save the basic settings for "ts-1" through "ts-8" (configured to connect to the IP address of the console server, at ports 7001-7008, respectively). I use a distinctive window size and text/background colors for these windows, and each connection is configured with a unique 'window name', and a unique log-file name. The distinctive window settings make it easy to tell which open windows are serial connections, versus network sessions when I'm debugging.
An advantage to using PuTTY for this, is I can also 'export' a copy the Windows Registry settings for these sessions onto my FLASH fob, and easily give the settings to someone who is going to borrow the kit, and VIOLA! They are ready to connect to the ports quickly and easily. PuTTY is small, and runs without needing to be 'installed', so I have a copy of that on the FLASH fob as well.
The final bit that makes the kit as easy to loan as it is for me to use it, is a 1-page README document (also on the FLASH fob...with a canned Conserver config snippet for this device, just in case), which outlines the default IP settings, serial speed settings, adapter and cabling clues, and basics about how to open a reverse-TCP session to a serial port. I also include clues and the password for configuring the device. (Add a few useful labels to the hub and console server, mark the wall-wart connectors with a color-code at the device-end, and things go pretty smoothly.)
I don't use it very often, but when I need it, it's ready to go! When your time is worth money, having a kit on the shelf is money well spent!
-Z-
The gist is, I started with a small 8-port console server, so I could use my laptop, a pre-configured telnet client, a crossover-Ethernet cable, and a handful of adapters to connect to various devices. I found that I often needed to be connected to the machine's network as well, so I added a small hub to the kit, as well as a small power outlet strip to my laptop bag.
I picked the Cyclades TS-800 8-port console server because it was small, was BREAK-safe, and ran from a 'wall wart' (power pack). I really wanted one that could run on 12-volts DC, so I could run the kit on car battery power, but couldn't find one. My laptop can also run from 12-volts DC (which could be handy in an emergency). Sadly, the TS-800 units are no longer sold by Avocent, but there are still a variety of small console servers on the market.
The small console server fit in the large pocket of my laptop bag, but limited how many cables I could carry, along with all the adapters. I finally fell to using a small, extra bag for the console bits.
I added a small 10-Mbps hub initially, so I could also do some packet sniffing, since most small switches don't have the ability to 'span' or 'mirror' ports. But, that bottleneck also throttled network access to the attached device, and I wasn't doing so much packet sniffing, so I 'traded up' to a Allied Telesyn AT-FS708LE 8-port 10/100 Mbps switch. This is a 12-volt DC device. It's small, lightweight, sturdy, and still available cheaply.
The kit now includes the switch, the console server, two crossover-Ethernet cables (1'- and 5'-long), an assortment of lengths of regular 8-wire CAT-5 cables, and an assortment of 24 Cyclades serial adapters. I also have a few 1'-long Cyclades null-modem (DCE-to-DTE crossed RJ-45 cables, and a few CAT-5e-rated female RF45 couplers. Add in the wall warts, and the kit lives in a 6-quart Sterilite plastic container about the size of a shoebox. Easy for security folks to see what is inside, but you don't want to put this in the belly of an airplane.
The Console Server is really the key to this kit, so here's what I've done to make it work;
First, configured the device as a console server, then copied the config file so I have an on-board copy, in case someone feels the need to change settings while they borrow it.
cp /etc/portslave/pslave.conf /etc/portslave/pslave.bkup
Make sure the backup config is saved into the unit's NVRAM. On the Cyclades, this means adding the file into /etc/config_files. (This is one reason I strip most of the comments out of my console server config files, since I'm basically saving two copies of the configuration file.) Now, if someone needs to change the config file, it's quick and easy to get back on the console, and copy the config back over the pslave.conf file, then 'saveconf' and reboot.
I also add an entry for my laptop into the /etc/hosts file on the console server, to reduce delays when making your reverse-TCP connections to the console server.
I had originally assigned different port speeds (19.2k, 38.8, 57.6, and 115.2) to ports 5 through 8, to make it quick and easy to access a high-speed port. But, I found that most ports are STILL at 9.6kbps as a default, and sometimes I needed more than 4 ports. In those cases when I needed a higher speed, I often needed more than one port at the higher speed at the same time. Since I found myself making many configuration changes I decided to revert the base configuration to 9.6k all 'round, but that's just explaining my reasons. You may want to do it your own way, and that's up to you.
I also pointed all the "extra" services (Radius server, syslog, etc) that the console server might want to use to the laptop IP address. I already use a small but of RFC-1918 address space, to reduce the chances of a conflict with the network that I may attach to. Pointing just to my laptop reduces the chance of the TS tripping any Intrusion Detection System (IDS) that might be watching the network. (I don't use the Syslog much anymore, but if I want to try it, that's one less part I need to configure.)
The current laptop is a PC, using PuTTY as the client tool. This lets me save the basic settings for "ts-1" through "ts-8" (configured to connect to the IP address of the console server, at ports 7001-7008, respectively). I use a distinctive window size and text/background colors for these windows, and each connection is configured with a unique 'window name', and a unique log-file name. The distinctive window settings make it easy to tell which open windows are serial connections, versus network sessions when I'm debugging.
An advantage to using PuTTY for this, is I can also 'export' a copy the Windows Registry settings for these sessions onto my FLASH fob, and easily give the settings to someone who is going to borrow the kit, and VIOLA! They are ready to connect to the ports quickly and easily. PuTTY is small, and runs without needing to be 'installed', so I have a copy of that on the FLASH fob as well.
The final bit that makes the kit as easy to loan as it is for me to use it, is a 1-page README document (also on the FLASH fob...with a canned Conserver config snippet for this device, just in case), which outlines the default IP settings, serial speed settings, adapter and cabling clues, and basics about how to open a reverse-TCP session to a serial port. I also include clues and the password for configuring the device. (Add a few useful labels to the hub and console server, mark the wall-wart connectors with a color-code at the device-end, and things go pretty smoothly.)
I don't use it very often, but when I need it, it's ready to go! When your time is worth money, having a kit on the shelf is money well spent!
-Z-
20070422
Relieve pressure in your shop!
We've got plenty of pressure with deadlines looming, new projects, and other 'people issues'. But the pressure I'm writing about today is torque.
For serial adapters that screw on (DB25, DE9, etc.), you shouldn't need to tighten them more than finger-tight. The screws are meant to keep the connector from being pulled out if the cable is tugged. Most of the small threaded nuts and screw-end on the adapters are not made for serious torque, and will likely break, or strip, if you apply too much pressure.
Finger-tight for you may be tighter than finger-tight for someone else that might need to work on the gear later. I don't want to make someone have to go get tools to remove serial adapters.
This goes for the screws for mounting your gear in cabinets or relay racks. You can tighten these hand-tight, but don't set your screw-gun to be an impact wrench! The lowest settings will probably be fine. (If it's not, you should make sure that you haven't cross-threaded the screw to begin with, rather than cutting new threads in the rails...because aluminum rails will strip easily, and steel rails will chew your screws easily. Let's try to not damage any parts today.)
The other damage that occurs from too much pressure is damaging the screwdriver bits and the screw-tops. It starts when the screw stops, and the drill keeps going, and the screwdriver bit starts to round over the screw head, but it's starting to damage the screwdriver bit as well! This makes it easier for the screwdriver bit to round over the next screwheads. (Take a good look at the philips bit in your screwgun today. If you don't have good, straight edges, it's time to turn down the torque, and either get out the file to renew your bit, or use a new replacement bit.)
The pressure you will save, will be the pressure on you in your next emergency. You'll be able to quickly remove an adapter without needing to go get tools. Your tools will easily remove and install screws, and your screws and rack rails won't be damaged by 'the last guy that worked on them'.
Once you set the torque on your screwgun to only 1 or 2, keep checking it, since there are probably other folks that borrow it. They'll likely change the setting, and not put it back. When you find it has been changed, you may be able to share this note with the culprit, and make things just a bit nicer in your shop.
For serial adapters that screw on (DB25, DE9, etc.), you shouldn't need to tighten them more than finger-tight. The screws are meant to keep the connector from being pulled out if the cable is tugged. Most of the small threaded nuts and screw-end on the adapters are not made for serious torque, and will likely break, or strip, if you apply too much pressure.
Finger-tight for you may be tighter than finger-tight for someone else that might need to work on the gear later. I don't want to make someone have to go get tools to remove serial adapters.
This goes for the screws for mounting your gear in cabinets or relay racks. You can tighten these hand-tight, but don't set your screw-gun to be an impact wrench! The lowest settings will probably be fine. (If it's not, you should make sure that you haven't cross-threaded the screw to begin with, rather than cutting new threads in the rails...because aluminum rails will strip easily, and steel rails will chew your screws easily. Let's try to not damage any parts today.)
The other damage that occurs from too much pressure is damaging the screwdriver bits and the screw-tops. It starts when the screw stops, and the drill keeps going, and the screwdriver bit starts to round over the screw head, but it's starting to damage the screwdriver bit as well! This makes it easier for the screwdriver bit to round over the next screwheads. (Take a good look at the philips bit in your screwgun today. If you don't have good, straight edges, it's time to turn down the torque, and either get out the file to renew your bit, or use a new replacement bit.)
The pressure you will save, will be the pressure on you in your next emergency. You'll be able to quickly remove an adapter without needing to go get tools. Your tools will easily remove and install screws, and your screws and rack rails won't be damaged by 'the last guy that worked on them'.
Once you set the torque on your screwgun to only 1 or 2, keep checking it, since there are probably other folks that borrow it. They'll likely change the setting, and not put it back. When you find it has been changed, you may be able to share this note with the culprit, and make things just a bit nicer in your shop.
Use the correct serial adapters, and trust them.
Today was a service window, and I was working in an old part of the network. I stumbled onto a broken DE9-toRJ45 adapter, dangling by it's wires. I swapped it out for a new one, from the proper vendor for the terminal servers in use, but there was no response via conserver.
"It was working fine last week." I'm told.
Looking further, I found a poor RJ45 termination, but the signals on on my signal tracer looked odd as well. This led me to the other end of the cable, where I found that I was looking at a USOC-Rolled cable (old CDDI-type wiring). This would have been a 'null-modem' if they had been using Cisco console servers, but they were not. Instead, they had only a couple leads correctly connected, and signal ground was not one of them. After a bit of frustration reaching more consoles, and reterminating those cables to be straight-through again, the network was back under our control. But why had they failed?
"But they've always worked like that." I'm told.
The wiring of the Cisco adapters, the null-modem (USOC-Rolled) cables, and the non-Cisco console servers wiring scheme had meant that signal reference was really be derived from the equipment chassis, across the power systems ground, between the console servers and the controlled devices. Today was they day that newer, fatter power circuits were installed, and moving the gear to different Power Distribution Units were too much.
The signal reference ground pin is extremely important, to prevent data errors, possible equipment damage, and possible injury to staffl handling the connections! (I'll share my 'bad ground, smoking gun' story another day, when I have more time.)
Using the correct adapters, and correct wiring, will lead to predictable results. Mixing and matching parts you have laying around with specialty cables will eventually cause you more headaches, and possibly more money than you will save. And the chances are good that you'll need to 'do it the right way' sooner or later. If your shop is as busy as the places I've been, you may as well do it right in the first place, because you may not have time to do it right later without sacrificing weekends or vacation time.
"It was working fine last week." I'm told.
Looking further, I found a poor RJ45 termination, but the signals on on my signal tracer looked odd as well. This led me to the other end of the cable, where I found that I was looking at a USOC-Rolled cable (old CDDI-type wiring). This would have been a 'null-modem' if they had been using Cisco console servers, but they were not. Instead, they had only a couple leads correctly connected, and signal ground was not one of them. After a bit of frustration reaching more consoles, and reterminating those cables to be straight-through again, the network was back under our control. But why had they failed?
"But they've always worked like that." I'm told.
The wiring of the Cisco adapters, the null-modem (USOC-Rolled) cables, and the non-Cisco console servers wiring scheme had meant that signal reference was really be derived from the equipment chassis, across the power systems ground, between the console servers and the controlled devices. Today was they day that newer, fatter power circuits were installed, and moving the gear to different Power Distribution Units were too much.
The signal reference ground pin is extremely important, to prevent data errors, possible equipment damage, and possible injury to staffl handling the connections! (I'll share my 'bad ground, smoking gun' story another day, when I have more time.)
Using the correct adapters, and correct wiring, will lead to predictable results. Mixing and matching parts you have laying around with specialty cables will eventually cause you more headaches, and possibly more money than you will save. And the chances are good that you'll need to 'do it the right way' sooner or later. If your shop is as busy as the places I've been, you may as well do it right in the first place, because you may not have time to do it right later without sacrificing weekends or vacation time.
20070413
Kudos to the Cyclades folks
Their product was developed across three continents, and sometimes you could find grammatical errors in their on-line tech notes (perhaps because the authors first language was not English?), but I have not found any techical errors in the command-line instructions of the older files.
To be honest, I occassionally took some liberties, trying to optimize the steps that they had outlined. But, if things didn't work the way I expected, I have always had success when I did it exactly the way they typed it.
As someone who owns and operates on a bunch of older Cyclades gear, I'm very thankful that Avocent has retained the old Cyclades files at http://global.cyclades.com. Access to the old information has proven to be invaluable for upgrading older units to newer code.
And, as a fan of documentation (see my Console Connection Guides...), I tip my hats to those who made sure that the original instructions were spot-on correct, every time! Thanks, folks! I hope the Avocent team will follow well in your footsteps.
-Z-
To be honest, I occassionally took some liberties, trying to optimize the steps that they had outlined. But, if things didn't work the way I expected, I have always had success when I did it exactly the way they typed it.
As someone who owns and operates on a bunch of older Cyclades gear, I'm very thankful that Avocent has retained the old Cyclades files at http://global.cyclades.com. Access to the old information has proven to be invaluable for upgrading older units to newer code.
And, as a fan of documentation (see my Console Connection Guides...), I tip my hats to those who made sure that the original instructions were spot-on correct, every time! Thanks, folks! I hope the Avocent team will follow well in your footsteps.
-Z-
20070408
Going back to the beginning
"I am waiting for you, Vizzni! You told me to go back to the beginning, so I have. When a job went wrong, you went back to the beginning!" - Inigo Montoya, Princess Bride -
Today's topic is a lesson in Change Control, sort of. More like Pre-Change Control.
Most manufacturers post their upgrade instructions. Some of these instructions are fine. Some are even exceptional. But few manufacturers offer instructions for how to downgrade their code. Yet, if an upgrade goes wrong, you will probably want a fall-back plan, to get you back where you were, at least until you can get the vendor to help past the problem(s).
Most console server devices store their OS and boot files in FLASH. But many of them cannot store more than one version of the OS in the on-board FLASH at a time. So, the upgrade process will overwrite the old version. If you plan to revert to the original version, you need to gather a few things before you start;
If your device has MD5 implemented, so that you can check the new version for integrity, you should also use MD5 to display the checksum for the current version before you start. (If you need to load the old version back again, you should know what the checksum will be.)
You keep all of the software CDs that came with your devices when they are new, right? (At least ONE copy for each platform, and for each different software version as you collect them.) You should also mark them (the CDs, Manuals, etc.) for the software version they contain. The cost of a bookcase is cheaper then an evening of your wasted time because you cannot easily find the information you need.
"But my vendor keeps all of this stuff on-line. Why bother to keep the old stuff?" you ask. Let me offer a few cases that happen more often than you might expect;
Keep the versions in separate directories, since sometimes the image names are identical, and you don't want to overwrite the old files when you add the newer files. Then, you will be ready to upgrade when the time comes, and you'll also be ready to downgrade again, if needed.
-Z-
Today's topic is a lesson in Change Control, sort of. More like Pre-Change Control.
Most manufacturers post their upgrade instructions. Some of these instructions are fine. Some are even exceptional. But few manufacturers offer instructions for how to downgrade their code. Yet, if an upgrade goes wrong, you will probably want a fall-back plan, to get you back where you were, at least until you can get the vendor to help past the problem(s).
Most console server devices store their OS and boot files in FLASH. But many of them cannot store more than one version of the OS in the on-board FLASH at a time. So, the upgrade process will overwrite the old version. If you plan to revert to the original version, you need to gather a few things before you start;
- A copy of the current code version
(You may be able to TFTP the file to a server from the device!) - At least a byte-count for the installed currently installed version
- Better is to have the MD5 checksum hash for the currently installed version
If your device has MD5 implemented, so that you can check the new version for integrity, you should also use MD5 to display the checksum for the current version before you start. (If you need to load the old version back again, you should know what the checksum will be.)
You keep all of the software CDs that came with your devices when they are new, right? (At least ONE copy for each platform, and for each different software version as you collect them.) You should also mark them (the CDs, Manuals, etc.) for the software version they contain. The cost of a bookcase is cheaper then an evening of your wasted time because you cannot easily find the information you need.
"But my vendor keeps all of this stuff on-line. Why bother to keep the old stuff?" you ask. Let me offer a few cases that happen more often than you might expect;
- The vendor goes out of business, and the website goes away.
- The vendor sells the product line, and the new vendor kills it off.
- The vendor gets acquired, and the old website goes away.
- The vendor decides old software is "support", and is worth money.
- Newer versions of software are too big to fit into the FLASH in your device.
- The upgrade instructions had a mistake.
- The new code doesn't like your old hardware.
- The vendor decides to remove old versions from the web, to encourage the adoption of newer versions.
Keep the versions in separate directories, since sometimes the image names are identical, and you don't want to overwrite the old files when you add the newer files. Then, you will be ready to upgrade when the time comes, and you'll also be ready to downgrade again, if needed.
-Z-
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