User Tools

Site Tools


when_to_migrate_a_classic_unix_system_and_where_to_migrate_to

Differences

This shows you the differences between two versions of the page.

Link to this comparison view

Both sides previous revisionPrevious revision
Next revision
Previous revision
when_to_migrate_a_classic_unix_system_and_where_to_migrate_to [2020/03/04 18:08] – [Should I emulate?] sgriggswhen_to_migrate_a_classic_unix_system_and_where_to_migrate_to [2020/03/04 19:04] (current) – [Should I emulate?] sgriggs
Line 78: Line 78:
   * You have some development environments on your VAX and some non-critical servers you'd like to ditch the hardware and emulate. Well, emulation is a good option in this case but why pay big bucks for it when SIMH is probably the best VAX emulator (free or otherwise). You should be using SIMH for free. It's easier to make work, has accurate emulation, generally results in some performance gains, and has a more sane and accessible system than the commercial VAX emulation suites. If you can get by without having support, then SIMH is always a better option for VAX emulation. The two commercial options should be 2nd and 3rd in that case.    * You have some development environments on your VAX and some non-critical servers you'd like to ditch the hardware and emulate. Well, emulation is a good option in this case but why pay big bucks for it when SIMH is probably the best VAX emulator (free or otherwise). You should be using SIMH for free. It's easier to make work, has accurate emulation, generally results in some performance gains, and has a more sane and accessible system than the commercial VAX emulation suites. If you can get by without having support, then SIMH is always a better option for VAX emulation. The two commercial options should be 2nd and 3rd in that case. 
   * You have moved most of your infrastructure to VMware or something similar and now you want to emulate your Unix or VMS hardware so you can move that to VMware too. That's not a great reason. You are going to probably spend (lots) more on the emulator than real hardware. So, is it **really** worth it? Also, running emulation inside VMware is something the emulation vendors love to crow about. Unfortunately, they like to ignore all the bugs and problems that causes. For example, if VMware short-changes your guest VM on a CPU tick what do you think the emulator is going to do? Let me answer: nothing good. Often we see VMS bugchecks and Tru64 kernel panics for this exact reason. Folks too high on VMware tend to make some fairly poor decisions just to shoehorn everything into VMware.    * You have moved most of your infrastructure to VMware or something similar and now you want to emulate your Unix or VMS hardware so you can move that to VMware too. That's not a great reason. You are going to probably spend (lots) more on the emulator than real hardware. So, is it **really** worth it? Also, running emulation inside VMware is something the emulation vendors love to crow about. Unfortunately, they like to ignore all the bugs and problems that causes. For example, if VMware short-changes your guest VM on a CPU tick what do you think the emulator is going to do? Let me answer: nothing good. Often we see VMS bugchecks and Tru64 kernel panics for this exact reason. Folks too high on VMware tend to make some fairly poor decisions just to shoehorn everything into VMware. 
 +  * You read the word "Cloud" in CIO magazine and now you are all excited to "move everything to the cloud". You are so excited, in fact, that you are willing to try to run the emulation package on an AWS virtual machine or some kind of "cloud" provider. Well, how is it "cloud" when they don't provide you an API to control the guest OS, but rather the host? You get nothing but an over-compliated VPS in that case. Right now, there aren't any truely cloud-aware emulation suites. What they do is manually run the emulator an a virtual Linux server. Nothing any more magical than that. Don't drink the whole bottle of "cloud"-aid and try to force a square peg into a round hole. 
 +
 +Here are some scenarios that would be **excellent** migration scenarios. 
 +
 +  * You have an old VAX or Alpha with no special hardware, the system isn't under heavy load, and all you really need is a box to run some old application software or host a legacy database. The system just sits on a single IP and runs it's application from local disks. You'd probably be happy with **any** emulator in this case. 
 +  * You have an old Sun box and it's presence in the data center is getting you dinged by security and other IT groups because of it's age. You know that running the hardware is cheaper than buying an emulator, but your problem is more than financial. You **must** get rid of that hardware so you stop being hassled by the clueless security people who (incorrectly) believe old systems cannot be secure or made secure. So you are willing to pay extra to have the hardware go away  while keeping the OS and applications it runs. Remember when it comes to Sun, your only valid option right now would be Charon-SSP and it's super-expensive. So, it has to be worth it! 
 +  * You have VAX systems in your environment and need development and non-production emulated instances to help with writing software or day-to-day testing. By all means, go get SIMH and you'll be pleased. 
 +  * You have an HP3000 PA-RISC box running MPE and HP's chaos has left you out to dry. You are worried that hardware might fail and you can't always get HP3000 parts anymore. They were rare systems to begin with. By all means get out your checkbook and be prepared to write a very large one for Charon-HPA. 
 +  * You are a sysadmin who just wants some dev environments for his AIX systems. Put in the effort and get Qemu running. It's not that hard to get AIX 4 through AIX 7 working on Qemu nowadays. Sometimes it requires a mksysb image, but that's not too terrible. 
when_to_migrate_a_classic_unix_system_and_where_to_migrate_to.txt · Last modified: 2020/03/04 19:04 by sgriggs

Donate Powered by PHP Valid HTML5 Valid CSS Driven by DokuWiki