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DO droplet slows down at peak times despite having loads of CPU and RAM capacity

Discussion in 'Virtual Private Server (VPS) hosting' started by MyWin, Oct 5, 2020.

  1. MyWin

    MyWin New Member

    Mar 13, 2019
    Local Time:
    11:36 AM
    This might be a silly question, but as my DO droplet with a xenforo forum slows down at peak times despite at most 25% of the CPUs or RAM being used (32gb ram / 16 dedicated cpus). Does this mean its a problem with DO and it's time to move? Or could it be an issue with my droplet that needs to be addressed? I've been reading the other threads here that aren't that good for DO, but most of the time the performance is great.

    It slows down often 8pm-10pm, which is the busiest time but probably the busiest time in the datacenter also.

    Stats for yesterday
  2. eva2000

    eva2000 Administrator Staff Member

    May 24, 2014
    Brisbane, Australia
    Local Time:
    9:36 PM
    Nginx 1.25.x
    MariaDB 10.x
    DigitalOcean in past has been consistently one of the slower VPS providers from tests at DigitalOcean - Linode - Vultr - Benchmarks - Upcloud - 13-Way VPS Server Benchmark Comparison Tests - Upcloud vs DigitalOcean vs Linode vs Vultr vs Hetzner. Maybe it's changed now?

    If running Centmin Mod 123.09beta01 or higher, you will have access to a cminfo top command which can also provide a summary of statistics - some of which are explained in info and linked articles below.

    FYI, CPU load optimal is 1.0 per cpu thread so 8 cpu thread normal = 8x1 = 8.0. 16 cpu server normal is 16x1 = 16.0

    so cpu load of 8 for
    • 2 cpu server = 8/2 = 4.0 load average
    • 4 cpu server = 8/4 = 2.0 load average
    • 8 cpu server = 8/8 = 1.0 load average
    When you type top command, hit number 1 to break down per cpu stats

    Centmin Mod is provided as is, so troubleshooting load issues is left to end user to do. However, there's many linux tools and scripts that can help you figure out what was causing the load issues and when.

    If you're providing info on this forum, more info might be helpful
    1. What version of Centmin Mod ? .08 stable or .09 beta ? If .09 beta when was it installed and when was last time you updated ?
    2. What's your VPS/Server hardware specifications ? cpu type ? memory available ? disk space ?
    3. Who's your web host ? Different hosts have different limits for server resource usage and some are more restrictive that others so it could just be their resource usage policy you tripped which may or may not be restrictive. If restrictive, then real solution would be finding a better web host. If not restrictive, then it's finding out what caused high cpu load.
    4. If running Centmin Mod 123.09beta01 or higher, you will have access to a cminfo top command which can also provide a summary of statistics - some of which are explained in info and linked articles below.
    Tools and commands you will want to read up on and learn for basic system admin tasks and troubleshooting.
    For example some commands which are also available automatically when you run cminfo top command
    Code (Text):
    top -bn1

    Code (Text):
    ps aufxw

    Code (Text):
    sar -q

    Code (Text):
    sar -r

    Code (Text):
    sar -q -f /var/log/sa/sa$(date +%d -d yesterday)

    Code (Text):
    sar -r -f /var/log/sa/sa$(date +%d -d yesterday)

    If you want to look at per process usage stats use pidstat run pidstat every 1 sec for 5 runs and sed is just to replace your main hostname with word hostname so mask your domain for posting on public places
    Code (Text):
    pidstat -durh 1 5 | sed -e "s|$(hostname)|hostname|g"

    Then in Centmin Mod 123.09beta01, you have access to cminfo sar commands for summary stats like
    Code (Text):
    cminfo top
    cminfo sar-cpu
    cminfo sar-mem
    cminfo phpstats

    For posting code you might want to use CODE tags for code How to use forum BBCODE code tags :)
  3. buik

    buik “The best traveler is one without a camera.”

    Apr 29, 2016
    Local Time:
    12:36 PM
    Time to move on.

    All VPS servers of all providers are limited. In case a specific VPS server requires too much computing power from her node. To prevent slowness on other VPS servers.

    So this is not a specific provider to blame but is unfortunately the disadvantage of a shared server.

    You have 16 cores available.
    Given the fact that most nodes have 2 cpus (example with EPIC 7601) with a total of 64 cores.

    Hundreds if not a thousand (small) VPS servers have to share all these part cores. That's why you notice slowness when your sites are busy but also the other sites that are on the same node, via the VPS server of your neighbor are quite busy, on busy hours.

    Then the provider, in cases like this, commonly uses CPU throttling and I/O limiting.

    I usually recommend a VPS server up to a maximum of 6 to 8 cores.
    After that it is advisable to consider a dedicated server.
    Where, just like a single-family detached home, you can use all resources.

    Because all available resources are only available to you.
  4. Colin

    Colin Premium Member Premium Member

    Oct 7, 2015
    Sheffield UK
    Local Time:
    11:36 AM
    MariaDB 10.1.#
    I am on Linode, I would get similar dips.

    check steal using glances or similar.

    I switched to Linodes version of ‘dedicated’ and not had a similar problem since.

    16 “core” 32gb of ram.

    slower CPU’s than shared, but better overall; apart from the cost bump.
    Last edited: Oct 11, 2020