PSU for server with 20+ HD's

[Discostu2120]

I'm looking to expand hard drive space on my back up server, but i don't think my current power supply is up to the task of powering the additional hd's.

My current setup is:
2x2.66 Xeon's
Tyan Tiger i7501R mobo
2x512mb registered ECC
Lian Li PC-V2000
8 250gb sata drives on rocketraid PCI-X
1 80 gb boot drive
PC Power and Cooling 510 EPS PSU


I will need significantly more hd space soon (have to back up a new Xserve storing 350 hours of DV) and the Lian Li case has room to fit as many as 14 additional internal drives (400 gb sata most likely). This server will be running 24/7 and stability/reliability is a priority.

So how do I power all these drives? Would it be possible to use an AT PSU for just the drives since the thing will always be on? Are there any single PSU's available that would be up to the task? I saw PC Power and Cooling now has an 850 Watt PSU with 68A total on the +12 V, would it work?

Thanks for your help.

 

[dandragonrage]

I'd go for redundant PSUs and I'd avoid AT supplies simply because they're old and low quality

 

[aug1516]

With staggered drive spinup I know the 850w PC Power Cooling model could do it just fine but I think you really need to look at redundant psu setups. You mentioned that uptime is important so you need to invest in something like this to ensure that uptime.

 

[Discostu2120]

Thanks for your suggestions. I don't think I need redundant power supplies because while I said stability/reliability were important this is just going to be a backup system that will be updated once at the end of every day. This is not the system that people are working off, for that we have an Xserve. So if a power supply fails I can just not run a backup for a few days until its replaced and it won't interrupt workflow. If by some strange chance the Xserve fails during that period I will still have a backup that is only a few days old.

What I can't have is a power supply that will supply inadequate power during the brief, but intensive backup period. The backup is connected via dual gigabit lines to two networks during backup, so it may be writing large amounts of data to quite a few of the 23 drives at once. If during this period the power supply runs out of juice and one of the drives loses its connection and is corrupted that would be very bad. I know I said it would be running 24/7, but the integrity of the backup is more important than the uptime.

I'm surprised to hear that AT power supplies are unreliable in general. Maybe something made for a large standalone disk array would work?

At this point the 850W with staggered spin up sounds like my only choice, but I would prefer to keep my 510 and just add something on for the additional drives.