Need to setup a high availability asterisk box

I need to set up a high available asterisk server that would be able to serve more than a hundred connexions at a time. We will use it for our callcenter.
For that, I’d like to know what is the hardware I should use.
I’m planning to use asterisk on a Linux Debian and I’m wondering if asterisk works with a 64 bits architecture (which should ingrease the performances I guess)
How much memory do you think should be necessary for that kind of server?
Would it be possible to set it up on a cluster configuration?
I’m looking at the HP servers. Do you think that getting an Itanium processor would be a great idea?

Thanks for your answers

Nah…you dont need to spend much money on machines with a big name, making 80% of the price…

Just get a good board, chipset, and (since asterisk is using many FP operations for audio) a P4 dual core.

2 or more GIG RAM (User “whoiswes” will tell you to get 8 GIG tho… :smiley: )

RAID 0+1 is also nice, fast access and not much load on the bus (no good safety, so backup the (little) datas nightly on another machine->Cronjob eg. )

The most power is used by soundconversion, eg. 729 to 711 etc. So as long as you work internal on your network, use 711 codec: No transcoding, fastest.

MOH is using power too, but if you use RAW format, your serverload will still be in the uper single-digit, sometimes 15-20% load.

All easy, 100 calls are no biggie, really not.

RAM isnt REALLY the problem under linux. Normally you go 860 MB (no highmem kernel) or 4 GIG (there is a 2 GIG no highmem patch out there tho).

CPU and fast bus is the key here, thats the whole rent.

So make sure you dont choose a P4 dual with a SIS chipset…

Have the system (Debian is good!) installed as light as needed, no GUI or graphical desktop stuff, plain boot into console.
Have all modules cards) and asterisk running as a respawn daemon and you can really make holidays after your 48h stability test said “GO”.