Question about multicore CPU

  • We are in the process of upgrading one of our production database servers from 2005 to 2008R2 along with the hardware upgrade.

    It's currently running on 4 x 2-core CPU just fine. There is a suggestion to buy 1 x 8-core CPU server in order to save the license cost (my understanding it would just require 1 CPU license). Is there any disadvantages performance wise to go with the 8-cores?

  • What is your current CPU utilization on average for that system? If you are running at anything above 40% utilization on average - you would need to add CPU's.

    If you are averaging less than that - you shouldn't have any problems with a single 8-core processor. However, make sure you are getting something that has more cache and is faster than the dual-core processors you currently have.

    Jeffrey Williams
    “We are all faced with a series of great opportunities brilliantly disguised as impossible situations.”

    ― Charles R. Swindoll

    How to post questions to get better answers faster
    Managing Transaction Logs

  • Current CPU utilization is averaging 30-35 %

  • You should be okay then - however, I would check with the business to see whether or not they anticipate any increased usage of the system over the next 3 to 5 years. If they do, you might as well go with 2 8-core processors now so you don't run into problems later.

    If you don't anticipate any significant increase in usage - you should be okay.

    Jeffrey Williams
    “We are all faced with a series of great opportunities brilliantly disguised as impossible situations.”

    ― Charles R. Swindoll

    How to post questions to get better answers faster
    Managing Transaction Logs

  • Thanks a lot, Jeff.

    One more CPU question. For SQL Server is it better to have more cache or faster speed?

    For example Xeon X5672 12 MB 3.2 GHz vs E7-2820 18 MB 2.0 GHz

  • vlad s (7/4/2011)


    Thanks a lot, Jeff.

    One more CPU question. For SQL Server is it better to have more cache or faster speed?

    For example Xeon X5672 12 MB 3.2 GHz vs E7-2820 18 MB 2.0 GHz

    Well, the typical answer is: it depends. It depends on how the system is used.

    I would make sure the new processors have at least the same as the old, and at least the same speed. If I was quoting this out, I would get the highest speed with the most cache that I could afford.

    Looking at the cost of the 8-core processors, it can get really expensive - real fast. I recently quoted out a processor upgrade for one of my clusters. Based upon an upcoming upgrade - the current system with 4 quad-core processors was just short of the recommended number of processors the vendor requires (their calculation put that at around 17 processors).

    Quoted out upgrading to 4 8-core processors for both nodes at just under $100K US. Way too expensive, so we went with slower processors - more cache and hex-core processors which totaled just over $20K.

    Jeffrey Williams
    “We are all faced with a series of great opportunities brilliantly disguised as impossible situations.”

    ― Charles R. Swindoll

    How to post questions to get better answers faster
    Managing Transaction Logs

  • Why did you shy away from the option with 16 cores? I'm assuming here that you could have quoted even cheaper than 20k!

  • Ninja's_RGR'us (7/4/2011)


    Why did you shy away from the option with 16 cores? I'm assuming here that you could have quoted even cheaper than 20k!

    Because we already had 16 cores (4 quad-core processors) and needed to get to a minimum of 17 based on the vendor calculation.

    It should be noted that before this upgrade we were averaging around 25% CPU utilization during business hours. Plenty of upgrade growth available, but the vendor wouldn't certify the system for their new version unless we exceeded the minimum CPU requirements.

    We could have gotten less expensive 8-core processors - which I did quote out also. However, for the cluster we were looking at a minimum of $50K to get the processors we would need for the system. There were slower 8-core processors available with less cache - but I didn't want to go that direction.

    We are scheduled to upgrade in August - but as of now, the CPU utilization is averaging less than 15% during peak usage. I expect after the upgrade that we will be back in the 20% average - and expected growth of the system over the next 3 to 5 years shouldn't require any upgrades to the hardware.

    Well, at least not for the CPU's - I can see us upgrading memory in a few years. That is, of course - based on current information. That could change tomorrow when I get into the office 🙂

    Jeffrey Williams
    “We are all faced with a series of great opportunities brilliantly disguised as impossible situations.”

    ― Charles R. Swindoll

    How to post questions to get better answers faster
    Managing Transaction Logs

  • It's hard to compare with existing one that is 4MB and 3GHz. I couldn't even find 8-core of this speed.

    If you had these options to replace existing one at a reasonable price:

    2 x X5672 (4C) 12 MB 3.2 GHz

    E7-2820 (8C) 18 MB 2.0 GHz

  • vlad s (7/4/2011)


    It's hard to compare with existing one that is 4MB and 3GHz. I couldn't even find 8-core of this speed.

    If you had these options to replace existing one at a reasonable price:

    2 x X5672 (4C) 12 MB 3.2 GHz

    E7-2820 (8C) 18 MB 2.0 GHz

    Well, this is where it comes down to how the system is used. Without knowing more, I really wouldn't be able to say for sure. I would probably lean more towards the faster processors, but then I would also have to consider the additional cost of licensing.

    If that is already factored in and considered - then the faster processors would be the choice. I really wouldn't want to go with slower processors, unless I was increasing the number of processors enough to feel comfortable with the slower speed or I was confident the slower processors wouldn't have a negative impact on the system overall.

    Jeffrey Williams
    “We are all faced with a series of great opportunities brilliantly disguised as impossible situations.”

    ― Charles R. Swindoll

    How to post questions to get better answers faster
    Managing Transaction Logs

  • How do you estimate the impact of a slower processor speed when you are dealing with mostly oltp env? Olap? Hybrid?

  • Ninja's_RGR'us (7/4/2011)


    How do you estimate the impact of a slower processor speed when you are dealing with mostly oltp env? Olap? Hybrid?

    Actually, I usually don't have to - because our vendor does all that testing for us and provides a minimum specification for us.

    It really comes down to being able to test and evaluate the system. Since that is not possible for most organization, my recommendation always comes down to getting the best you can for the budget you have for new systems.

    For upgrades, I usually recommend at least the same speed and cache - or as close as possible, again - for the budget you have.

    I wouldn't consider dropping from 3.0 to 2.0 on the speed, unless I was convinced that the slower speed would give me other benefits (e.g. more cache, more cores, etc...) and we were not having any other issues.

    Jeffrey Williams
    “We are all faced with a series of great opportunities brilliantly disguised as impossible situations.”

    ― Charles R. Swindoll

    How to post questions to get better answers faster
    Managing Transaction Logs

  • Jeff, Thanks a lot for being so helpful.

    Considering that we are going to triple the amount of RAM on a new box I’ll probably go with the fastest 8-core I could find:

    Xeon 8C E7-8837 2.67GHz/24MB

  • That looks good to me - good luck.

    Jeffrey Williams
    “We are all faced with a series of great opportunities brilliantly disguised as impossible situations.”

    ― Charles R. Swindoll

    How to post questions to get better answers faster
    Managing Transaction Logs

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