Dual CPU's and redundancy

[jhablitzel]

This question may seem rather simple to those of you who know hardware, but I can't find a direct answer anywhere. When a PC (server or workstation) has dual or multiple CPU's installed, are these CPU's redundant. In other words, if one fails will the others keep working. My observation was that multiple CPU's was just for increased performance. However, we have gotten a lot of requests from our customers (we work in public safety software) requesting multiple CPU's for redundancy. If they won't work that way, then I want to be able to tell them that and have something to back me up. If anyone knows of any good articles on this area, as well as multiple CPU technology in general, I would be interested as well.

 

[nlm9802]

it is very very rare for a cpu to fail, therefore, multiple cpu's are more for load balancing then redundancy.
I know that some of the dual cpu motherboards I have worked with will allow you to select single cpu mode and will boot with a placeholder in the 2nd cpu slot.

spending money on a second processor simply for redundancy is a waste of money in my opinion, as most processors will last longer than their useful life span. If you have a computer that supports it, and the cpu is getting close to maxing out, then yes, it may be worth the $$ to get another cpu instead of buying a new machine. Not just for a "in case the cpu fries" though

Nick
Computer Support, no not just hardware.. I support everything

 

[JimInKS]

Disclaimer - I am not an expert in this area!

I agree with Nick, the processor is about the most reliable part of a system (baring a cooling fan failure). PC class dual processor systems are not designed to be fault tolerant. You might even be able to argue that since the mother board is more complex it is more prone to failure.

Most other components are more likely to fail. Network cards, Power supplies, Hard drives, Controllers. You can get some redundancy in these areas. Redundant Power supplies, RAID hard drive arrays, etc.

If you are wanting a completely fault tolerant system I'm sure you're talking big bucks. My opinion is that Software failures will cause more down time than hardware failures.

Here is a web site I found that markets high availabilty or fault tolerant systems. It may give you some insight.

http://www.disastertolerance.com/index.htm