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(A) Lease vs. Buy: If you can swing it, lease them instead - tax benefits, etc. (B) Do you really need 8 cores per box? I.e., you can get used dual-dual machi

by johnm 18y ago

(A) Lease vs. Buy: If you can swing it, lease them instead - tax benefits, etc. (B) Do you really need 8 cores per box? I.e., you can get used dual-dual machines a lot cheaper than 50% of the price of the dual-quad machines. (C) If you know what you want and are buying new then going with a white box builder is significantly cheaper than buying from Dell/HP/etc. I've been pretty happy with ASA especially since they've delivered/picked-up/serviced machines directly to/from/in our colo but there are plenty of decent vendors and they most end up using SuperMicro-based systems anyways. (D) Do you really need 1U? Why? Power/cooling issues are putting more constraints on things than size at many places and a 2U is often cheaper, more flexible, fixable, etc. (E) Really knowing exactly what you want can make a big difference in talking with the salespeople. Buying at the end of the quarter is a good thing if you can swing it. (F) More ram is more better and 32GB is the current sweet spot in terms of lots of memory for a good price. Pay particular attention to the motherboards that you're considering as there can be a price premium at the various steps depending on if you need the flexibility to upgrade the memory a lot later. (G) You mention that disk isn't much of a concern. Is that because you just want lots of compute nodes or because you're putting everything into a NAS/SAN or what?

slackerIII 18y ago
I was thinking 1U because I don't need a lot of disk and it gives me more options about how many I can put in each cage. What kind of power limitations have you run into? As for the disk, I just don't have a lot to store.
- philjr 18y ago
  Normally there is a power threshold measured in Kilowatts or amps on your cabinet. Amps is generally easier to work with. 16A or 32A would be pretty standard. Really, you need to ask your colo facility. Be careful with a 32 amp A & B feed if you're using them for redundancy. Ideally you don't want to overload the A or B feed if one of them is down. The advice given to you regarding Dell servers is pretty good. They also have a power estimator on their website which you can download which give really good indicators as to what your power usage might be. Basically, the chances are you wouldn't be able to pack 42 1u servers into a 42U cab and power is becoming more and more of an issue. Extra note: newer generation dell servers are much less hungry than the old ones. The PE 2950's are great 2U machines, easy to work with and I'd vote for them over the equivalent 1U form factor 1950s from my experience.
- johnm 18y ago
  If you don't need to cram a lot of boxes into a tight space then 2U will usually give you better airflow and cooling. Also, when those on-motherboard NICs die, you can more easily/cheaply add additional NIC cards to the 2U boxes. In terms of power, that's actually the main limitation in most colo's these days. Some colos are down at 15 amps per rack, many seem to be in the 20 amps per rack, and some you can get up to 30 but you will pay for that one way or another. Even at 30 amps per rack, for the kind of machines that you're talking about you are still likely to be less than about 20 machines per rack. I just spec'd a build out of the same horsepower & ram but with more juice for e.g., FC cards to a SAN and the safe limit was 16 machines in a 30 amps per rack colo and 8 machines in a 15 amps per rack colo. Shopping around for power information can be tricky because some of the colos like to play marketing games to get you to think there price is better than others but the power charges can eat you alive if you need more than what they allocate in their base charges.

by johnm 18y ago

slackerIII 18y ago

I was thinking 1U because I don't need a lot of disk and it gives me more options about how many I can put in each cage. What kind of power limitations have you run into? As for the disk, I just don't have a lot to store.

philjr 18y ago
Normally there is a power threshold measured in Kilowatts or amps on your cabinet. Amps is generally easier to work with. 16A or 32A would be pretty standard. Really, you need to ask your colo facility. Be careful with a 32 amp A & B feed if you're using them for redundancy. Ideally you don't want to overload the A or B feed if one of them is down. The advice given to you regarding Dell servers is pretty good. They also have a power estimator on their website which you can download which give really good indicators as to what your power usage might be. Basically, the chances are you wouldn't be able to pack 42 1u servers into a 42U cab and power is becoming more and more of an issue. Extra note: newer generation dell servers are much less hungry than the old ones. The PE 2950's are great 2U machines, easy to work with and I'd vote for them over the equivalent 1U form factor 1950s from my experience.
johnm 18y ago
If you don't need to cram a lot of boxes into a tight space then 2U will usually give you better airflow and cooling. Also, when those on-motherboard NICs die, you can more easily/cheaply add additional NIC cards to the 2U boxes. In terms of power, that's actually the main limitation in most colo's these days. Some colos are down at 15 amps per rack, many seem to be in the 20 amps per rack, and some you can get up to 30 but you will pay for that one way or another. Even at 30 amps per rack, for the kind of machines that you're talking about you are still likely to be less than about 20 machines per rack. I just spec'd a build out of the same horsepower & ram but with more juice for e.g., FC cards to a SAN and the safe limit was 16 machines in a 30 amps per rack colo and 8 machines in a 15 amps per rack colo. Shopping around for power information can be tricky because some of the colos like to play marketing games to get you to think there price is better than others but the power charges can eat you alive if you need more than what they allocate in their base charges.