My concerns are a bit similar to the last two commentors, but I have a few new ones too.
Given the 3x increase in accounts, isn't a ~3x cpu and ~3x memory increase just breaking even?
If they were the same architecture then yes, but it's much newer processors which are much more efficient and can do more work per clock cycle. At the end of the day if you're not happy with the performance on the new server, you're welcome to cancel the service at any time.
I realize not all accounts are created equally, but I'd expect resellers to be wanting to push their stuff pretty close to the limit.
There is no such thing as a reseller on a semi-dedicated server.
Also, how about disk IOPS?
If the server for any reason isn't able to keep up with the IOPS demands of the accounts we'll bring another server offline and split the server down. We'd love to run SAS 15k RPM drives in the semi-dedicated servers however as most of the semi-dedicated customers use 15+ GB each we'd have to double or triple the semi-dedicated pricing to make it feasible.
As for the increased risk from 3x as many accounts, are the old servers going to have different IPs on the new combined servers? So that if something bad happens requiring a null route to be applied or someone gets themselves (or gets exploited and ends up) on a spam blacklist, it won't affect any more than it does currently.
None of our servers are blacklisted, and we've only had one instance of that happening over the last 3 years across all of our hardware. Beyond that - accounts currently on dedicated IPs will be on their own IP and then accounts on shared IPs are going to be spread out over various IPs as not to have an "all your [sites]/eggs in one [IP]/basket" type of situation.
Since you are colo-ing instead of leasing, you are responsible for hardware failures now yes? Do you have spare parts at the datacenter, or do they have the correct parts on hand, or do we have to potentially wait for shipping from you or the store to the datacenter?
We're keeping spare parts on hand at the facility and using 100% enterprise class hardware. The facility can provide us spare hardware if we go through our spare equipment, we would just have to pay them for it.
Also just out of curiosity, is this data center local to you (that would certainly help with the previous scenario), or are you relying on remote help?
It's not local to us however we've negotiated very good remote assistance terms with the facility should it come down to a hardware issue. Beyond that we have KVM on every server so essentially short of pure hardware failure we're capable of being 100% self-sufficient.
Been happy with everything so far, so I'll give you the benefit of the doubt and hope everything goes smooth.
Sounds good - like I said, you're always welcome to cancel if you're unhappy with the service after the transfer however I would probably wait until then to make that decision