Comparing Server CPU Capabilities?
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@scottalanmiller said in Comparing Server CPU Capabilities?:
Is there a reason to expect the company to be adding so many more computationally heavy workloads?
I don't know that we would be doubling it, I was just using that as an example on how I can associate some numbers to this planning process. If someone says, we are spending $25K per server, how much more capability/capacity do we get from our investment? For RAM and storage, that is easy- Faster and greater RAM and storage capacity, adding tiered storage by introducing SSDs in RAID5 and using NLSAS in RAID1 for "bulk" storage.
Apparently, due to the complexity and advancements in CPU tech, there isn't an easy way to calculate or express a tangible value for it.
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@NetworkNerd said in Comparing Server CPU Capabilities?:
Do you have any issues with high CPU ready times today?
Here is the CPU Ready chart (previous month) at the host level for the first host . It has 9 active VMs.
Here is the CPU Ready chart (previous month) at the host level for the second host. It has 17 active VMs.
The differential between the two, in terms of number of VMs, is due to the current storage constraints. One of the VMs on the first host has significantly greater storage usage than all others. This has grown over time and forced the uneven allocation of VMs and has compounded over time.
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@IRJ said in Comparing Server CPU Capabilities?:
@wrx7m said in Comparing Server CPU Capabilities?:
@scottalanmiller So, If my average CPU usage on one of the hosts is over 50% and max is 95% for the past 6 months, I can't use that to say how much more CPU I need if I wanted to double the number of running VMs with similar performance needs?
How can you define similar, though?
Whatever my average CPU utilization is for my existing VMs on my existing hosts with 2 x Intel Xeon E5-2609 v1 CPUs.
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You have E5-2600 V1, V2, V3, V4 and Scalable Gen1 and Gen2 as the latest generation. So the new CPU is 5 generations newer.
A rough number is that you get about 10% increase in performance per core for each generation, using the same clock speed. Sometimes it's more and often it's less but memory speed have also increased so I think 10% is a fair number. That said, a lot of the overall performance increases has been from increasing the clock speed or in most cases increasing the number of cores.
Anyway, 5 generations @ 10% increase is a 60% increase. Add clock speed increase from 2.4 to 2.8Ghz and you have 87%. Add going from 2x4 cores to 16 cores and you have a total of about 3.7 times CPU performance increase.
To keep the actual performance of the VMs the same but run 3-4 times as many VMs, you would also need the same increase in storage and in network performance. That is quite possible if you are also moving from spinning disks to ssd and perhaps from 1GbE to 10GbE on the hypervisors. You also need 3-4 times as much RAM of course.
Depending on what you are upgrading I'd say the conservative number is you will get twice the capacity and the optimistic number is that you have four times the capacity.
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@wrx7m said in Comparing Server CPU Capabilities?:
https://www.cpubenchmark.net/compare/Intel-Xeon-Gold-6242-vs-Intel-Xeon-E5-2609/3516vs1429
The numbers in the link are a little misleading because you are going from dual E5-2609 v1 to single 6242. The multi core performance for that is 8162 versus 25313 for the 6242.
One sample could be misleading but you could always check for other similar CPUs. To me the numbers looks reasonable though.
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@wrx7m said in Comparing Server CPU Capabilities?:
I don't know that we would be doubling it, I was just using that as an example on how I can associate some numbers to this planning process. If someone says, we are spending $25K per server, how much more capability/capacity do we get from our investment? For RAM and storage, that is easy- Faster and greater RAM and storage capacity, adding tiered storage by introducing SSDs in RAID5 and using NLSAS in RAID1 for "bulk" storage.
The problem there is... if you don't need it, that capacity is wasted. So unless you need X capacity, whether you get it or not for the investment is moot.
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@Pete-S said in Comparing Server CPU Capabilities?:
The numbers in the link are a little misleading because you are going from dual E5-2609 v1 to single 6242. The multi core performance for that is 8162 versus 25313 for the 6242.
Yes, you have to remember to double the numbers when looking at the multi-threaded composites. But you also have to shave a little bit for the dual socket overhead. but doubling is close.
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Another element to consider is how the newer gen CPUs deal with the Spectre / Meltdown and friends when compared to the older gen of CPU. Also keep in mind that if you're going single socket your RAM options will be limited compared to dual socket. I'm not saying that one or the other is better, as it all depends on budget and purpose, but I didn't notice either factor being mentioned when skimming the thread.
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For the analysts of the current utilization of your hosts, best bet would be running a LiveOptics Collection toolkit. In result, the Report will present you with granular details as to the utilization of your CPU, RAM and storage.
After the run is complete, it would be highly beneficial to discuss your requirements to the future solution with the vendor of your choice. -
@Pete-S said in Comparing Server CPU Capabilities?:
To keep the actual performance of the VMs the same but run 3-4 times as many VMs, you would also need the same increase in storage and in network performance. That is quite possible if you are also moving from spinning disks to ssd and perhaps from 1GbE to 10GbE on the hypervisors. You also need 3-4 times as much RAM of course.
Depending on what you are upgrading I'd say the conservative number is you will get twice the capacity and the optimistic number is that you have four times the capacity.Thanks. The majority of workloads will be moved to SSD, with the file servers running on spinning disks. I already have 2 10Gig for VMs and 2 for vmotion, per server. That is a good point about the RAM. Current RAM utilization is a bit constrained. Each server only has 128GB. I am looking at 320 GB. This will allow for some growth and also running all VMs on a single host if necessary.
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@wrx7m said in Comparing Server CPU Capabilities?:
@Pete-S said in Comparing Server CPU Capabilities?:
To keep the actual performance of the VMs the same but run 3-4 times as many VMs, you would also need the same increase in storage and in network performance. That is quite possible if you are also moving from spinning disks to ssd and perhaps from 1GbE to 10GbE on the hypervisors. You also need 3-4 times as much RAM of course.
Depending on what you are upgrading I'd say the conservative number is you will get twice the capacity and the optimistic number is that you have four times the capacity.Thanks. The majority of workloads will be moved to SSD, with the file servers running on spinning disks. I already have 2 10Gig for VMs and 2 for vmotion, per server. That is a good point about the RAM. Current RAM utilization is a bit constrained. Each server only has 128GB. I am looking at 320 GB. This will allow for some growth and also running all VMs on a single host if necessary.
I'm really wondering if you have a need for two host right off the git go.
Scott's comment about buying more than you need for today is something to seriously consider.
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@wrx7m said in Comparing Server CPU Capabilities?:
@Pete-S said in Comparing Server CPU Capabilities?:
To keep the actual performance of the VMs the same but run 3-4 times as many VMs, you would also need the same increase in storage and in network performance. That is quite possible if you are also moving from spinning disks to ssd and perhaps from 1GbE to 10GbE on the hypervisors. You also need 3-4 times as much RAM of course.
Depending on what you are upgrading I'd say the conservative number is you will get twice the capacity and the optimistic number is that you have four times the capacity.Thanks. The majority of workloads will be moved to SSD, with the file servers running on spinning disks. I already have 2 10Gig for VMs and 2 for vmotion, per server. That is a good point about the RAM. Current RAM utilization is a bit constrained. Each server only has 128GB. I am looking at 320 GB. This will allow for some growth and also running all VMs on a single host if necessary.
By the looks of it, you have 12 memory slots for use with your single CPU, so you have more than enough room.
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@Dashrender said in Comparing Server CPU Capabilities?:
@wrx7m said in Comparing Server CPU Capabilities?:
@Pete-S said in Comparing Server CPU Capabilities?:
To keep the actual performance of the VMs the same but run 3-4 times as many VMs, you would also need the same increase in storage and in network performance. That is quite possible if you are also moving from spinning disks to ssd and perhaps from 1GbE to 10GbE on the hypervisors. You also need 3-4 times as much RAM of course.
Depending on what you are upgrading I'd say the conservative number is you will get twice the capacity and the optimistic number is that you have four times the capacity.Thanks. The majority of workloads will be moved to SSD, with the file servers running on spinning disks. I already have 2 10Gig for VMs and 2 for vmotion, per server. That is a good point about the RAM. Current RAM utilization is a bit constrained. Each server only has 128GB. I am looking at 320 GB. This will allow for some growth and also running all VMs on a single host if necessary.
I'm really wondering if you have a need for two host right off the git go.
Scott's comment about buying more than you need for today is something to seriously consider.
Well, since this is production, yes, we do need 2.
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@wrx7m said in Comparing Server CPU Capabilities?:
Well, since this is production, yes, we do need 2.
You might need two. But being production wouldn't tell us that. Only HA environments needs two. And that's super rare.
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@scottalanmiller said in Comparing Server CPU Capabilities?:
@wrx7m said in Comparing Server CPU Capabilities?:
Well, since this is production, yes, we do need 2.
You might need two. But being production wouldn't tell us that. Only HA environments needs two. And that's super rare.
If we don't have any of our servers running, no one can do any work except for chat and email. I don't have the exact cost, but I can say that it is expensive.
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@wrx7m said in Comparing Server CPU Capabilities?:
If we don't have any of our servers running, no one can do any work except for chat and email. I don't have the exact cost, but I can say that it is expensive.
Try ballparking it. And ballpark the cost of the second server with all of the setup, risks, and licensing.
Downtown is usually shockingly cheap. Like, often 1-5% as much as people think that it is. Especially when things like chat and email keep working! Those are the core apps.
What functions stop in the first five minutes, hour, day if the server goes down?
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@scottalanmiller said in Comparing Server CPU Capabilities?:
@wrx7m said in Comparing Server CPU Capabilities?:
If we don't have any of our servers running, no one can do any work except for chat and email. I don't have the exact cost, but I can say that it is expensive.
Try ballparking it. And ballpark the cost of the second server with all of the setup, risks, and licensing.
Downtown is usually shockingly cheap. Like, often 1-5% as much as people think that it is. Especially when things like chat and email keep working! Those are the core apps.
What functions stop in the first five minutes, hour, day if the server goes down?
Order processing will stop completely. If no one has access to the ERP and other LOB apps we use, they can't do much of anything.
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The rule of thumb is that downtime is cheap and HA is expensive. It's far from always the case. But it is generally true. It is a super rare company that feels even complete outages for a few hours in any significant way, and very rare that a company comes to a full stand still without their computers.
And if you can keep somethings still working, even better.
From the business side of things, we always want our time to sound 100x more expensive than it is. We talk in terms of our busiest day, not our average. We talk in terms of "lost money", when really it is normally "aggravation." We talk in terms of "outages" rather than "inconvenient temporary work arounds."
Mitigation techniques for an outage for most companies are pretty strong. Some work just keeps on going, at least for a while. Some functions keep going on. Some people switch to available tasks to stay busy. Some people take breaks or go home. Cost reduction in labour, insurance, power, etc. all offset outages. And most companies can simply shift tasks to another time. No company runs at 100% capacity 24x7, none. It's not sustainable. Some companies have very little capability to make up work later, but most can.
It's actually not uncommon for full day outages to end up having an "effectively zero dollar" cost when it is all said and done.
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@wrx7m said in Comparing Server CPU Capabilities?:
Order processing will stop completely. If no one has access to the ERP and other LOB apps we use, they can't do much of anything.
Sure, but what does that really cost you? I've worked in a lot of factories and even at IBM this would have cost us almost nothing... because over the course of a few days or maybe a couple weeks we'd just run slightly faster and catch up.
A single server outage is rarely more than a few hours, maybe a day at most. A second server, HA or just a second server, is to reduce that time from "several hours" to "minutes or maybe an hour tops." The average outage that HA protects against is actually just a few minutes. Full outages, like from total hardware failure, are crazy rare and if you are in a major city, part swaps are normally just a few hours.
Add on to that the risk that the HA system itself might cause an outage and it gets harder to justify.
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My question is - do you have actual HA because you have two servers?
