redundancy

JGraham · 13th July 2005

Just a question..

After investing in redundant solutions (power supply/nic specifically) do providers generally support this?

For example, at little or no cost could my server have a second power connection, and two network ports? Of course, in theory no extra resources would be used, as the redundant solutions would only be used when required.

I hope that makes sense!

Karl · 13th July 2005

PSUs - both would be drawing power, you're also taking up infrastructure that can be used to make money elsewhere, so it will cost you more.

James[UH] · 13th July 2005

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JGraham · 13th July 2005

Thanks for the replies guys.

I was moreso referring to redundancy of the server itself. If the two PSUs were connected to the same PDU would they draw more power than one? I dont see why, because surely the server would use the power it requires regardless of how many PSUs attached.

Bottom line is, ive heard many a tale of PSUs failing, it would save alot of time and money if both were connected and one failed right? But I guess the solution is to lease my own rackspace from the DC and do what I like with it...

James[UH] - do you charge those customers extra for using two power connections?

Karl · 13th July 2005

Two PSUs = roughly twice the power draw in our experience. If you use good quality PSUs, from the likes of Zippy etc. you're not all that likely to loose a PSU within it's useful lifetime.

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markcastle · 13th July 2005

If a clients server has two power supplies we always connect both up and don't charge extra for it.

Maff · 13th July 2005

We've just started using static bypass controllers in our racks for a new 'venture', and these work well. The switch takes feeds from A and B power supplies which are diversely routed to the rack from different UPS and national grid feeds. Then if the power to that UPS (or the UPS) fails, the switch flicks over to the alternate supply with no loss in power.

This allows us to connect dual power supply servers to diverse feeds at no extra cost (as it's provided as standard by the DC to us).

markcastle · 14th July 2005

Which DC Matt.... GS?

luke · 14th July 2005

Quote:

Originally Posted by Maff

We've just started using static bypass controllers in our racks for a new 'venture', and these work well. The switch takes feeds from A and B power supplies which are diversely routed to the rack from different UPS and national grid feeds. Then if the power to that UPS (or the UPS) fails, the switch flicks over to the alternate supply with no loss in power.

And if the switch its self fails?

Maff · 14th July 2005

In Dataplex Budapest.

The switches are internally redundant, supplied by MGE UPS Systems. They also have RS232 outputs so you can find when then power to a certain feed tripped, and other data.

Karl · 14th July 2005

Maff - You got MSN/ICQ etc.? Wouldn't mind a quick word about them (We actually get A + B feeds) and a couple of other bits.

Cheers,

othellotech · 15th July 2005

[QUOTEJ
After investing in redundant solutions (power supply/nic specifically) do providers generally support this?
[/quote]
Some of us yes.

Quote:

For example, at little or no cost could my server have a second power connection, and two network ports? Of course, in theory no extra resources would be used, as the redundant solutions would only be used when required.

Not sure why you think it shoudl be little or no cost

2 psu's will take up two power outlets
draw more power than a single psu
to be done correctly as per other posts, 2nd psu should connect to separate kit, on separate phases of ups/building power etc, which all costs money.

2 network ports which not using twice the transit, use two ports on the switch, etc, and unless done with some form of teaming with nat, cannot both be active on teh same ip ready for failover anyhow.

Yes psu's fail, *sometimes* having a redundant psu helps (althouhg we've seen the boxes still end up rebooting themselves) - other times the psu going also takes out the motherboard - so you're still dead.

similarly hard-drives fail, cpu's fail, fans fail, onboard nics fail ... essentially every component can and eventually will go wrong. buying better kit in the first instance can limit that, although i've know cheap case/psu combinations run for 5 years - its all to do with environment, cooling, quality/manufacturer and luck.

JGraham · 16th July 2005

Quote:

Originally Posted by othellotech

Some of us yes.
Not sure why you think it shoudl be little or no cost

2 psu's will take up two power outlets
draw more power than a single psu
to be done correctly as per other posts, 2nd psu should connect to separate kit, on separate phases of ups/building power etc, which all costs money.

I agree it may draw more power, but that shouldnt be a problem as long as its within the limits of the contract. Personally, having each PSU connect to the same PDU would suffice. The system is not exactly mission critical.

Quote:

Originally Posted by othellotech

2 network ports which not using twice the transit, use two ports on the switch, etc, and unless done with some form of teaming with nat, cannot both be active on teh same ip ready for failover anyhow.

There are HP drivers installed which do the network teaming seamlessly. Check it out, its quite a powerful tool. This would cost the provider nothing. Additional ports I understand may be an issue. However, if there are spare ports then why not

Quote:

Originally Posted by othellotech

Yes psu's fail, *sometimes* having a redundant psu helps (althouhg we've seen the boxes still end up rebooting themselves) - other times the psu going also takes out the motherboard - so you're still dead.

similarly hard-drives fail, cpu's fail, fans fail, onboard nics fail ... essentially every component can and eventually will go wrong. buying better kit in the first instance can limit that, although i've know cheap case/psu combinations run for 5 years - its all to do with environment, cooling, quality/manufacturer and luck.

When we're talking decent hardware (HP), most of those failure points highlighted are taken care of. Hard drives, we have raid with online spares. CPUs, with two installed, and one fails, the system automatically reboots and uses the other. Redundant fan kits are available that simply "snap" in. Onboard nics ive discussed.

Anyway, question has been answered- looks like i'm going to have to wait till I can afford my own rack to implement my own redundancy systems.

othellotech · 16th July 2005

JGraham:I agree it may draw more power, but that shouldnt be a problem as long as its within the limits of the contract

JGraham:This would cost the provider nothing. Additional ports I understand may be an issue. However, if there are spare ports then why not

JGraham:looks like i'm going to have to wait till I can afford my own rack to implement my own redundancy systems.

I never disagreed with the need or application of redundancy - we have plenty of colo clients with multiple psu's connected to separate APC's on separate phases, multiple nics connected to multiple switches in separate vlans etc etc

The "question" I had was merely why you though it shouldnt cost extra for the additional power, the additional power port, the additional phase run to the rack, the additional apc, the additional switch, the extra setup etc.

Its the different view between consumer and service provider - you view them as "spare" switchports which cost nothing - we see a 3 grand switch with maintenance of 1k with 24 ports and give each of them a "cost" off £125+£42 ~ equating to appx £15/month - if you want an extra one fine, depending on the service you're taking we may/may not want to charge you for it.

because it's not currently utilised doesnt make business sense to give it away free - especially as it then means you dont have it to sell. I personally feel you should charge people for what they use rather than charging them all more because some might use extras.

Plenty of providers will offer you the additional features you need to improve redundancy, you dont need you own rack for it, but if you're heading that route - ideally you need two racks in case 1 falls over