Email server, where is the bottleneck?

Discussion in 'Questions and Answers' started by libro22, May 17, 2017.

  1. libro22

    libro22 Member

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    If I'm to put up a server dedicated for emails (currently being used for IMAP and Roundcube), which bottleneck should I focus on? Is it CPU or memory? I'm thinking of getting a VPS first (both companies I'm checking out have SSDs, so I don't think I/O should be an issue). They just differ with Dedicated CPU vs Shared, and Higher vs Lower memory.
     
  2. CenTex Hosting

    CenTex Hosting Member Verified Provider

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    How many Emails are you talking about sending? If you are just sending normal use then no worries about bottleneck. Now if you are trying to send millions of emails at a time. There there are a few things to look at. first would be the host and do they allow mass mailing, 2 what is the mail rate limit per hour they have set.
     
    libro22 likes this.
  3. libro22

    libro22 Member

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    My current server is actually sending about 10k emails a month, valid transactional and regular emails. Active domain senders are around 10 with less than 10 active accounts each.

    I dont mind deliverability as I'm using mailchannels. Though I currently have local anti-spam processes and thinking of offloading this to a 3rd party anti spam.

    Current server is getting loads of 4-5 out of 16 CPUs (Dedicated Server) on regular work hours as active IMAP and roundcube processes are filling it up. This is what I'm concerned of if I move them to VPS with hopes of future expansion.
     
  4. Nick

    Nick Moderator Moderator

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    With those kinds of loads you may get away with having a VPS. Are those loads only during peak hours and if so, for how long? What's the server that you currently have?
     
    libro22 likes this.
  5. libro22

    libro22 Member

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    A pretty old L5520 :)

    Yep, I pretty much guessed that VPS would suffice. But I still don't know which resource IMAP and Roundcube use the most, is it CPU or memory? And where it would benefit more.
    I can't base it on my usage as my disks are pretty slow (and old) :(
     
  6. fm7

    fm7 Active Member

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    8 cores with hyperthreading ~10 "CPUs" and load 5 usually implies 5 cores 100% in use. You are using a lot of processing power that I guess VPS providers probably won't be happy to sustain. I suggest you to use PERF to learn about your actual requirement -- "load" is crapware.
     
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  7. libro22

    libro22 Member

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    I've checked my stats and my disks are the culprit for this, util is around 60-90 that's why I can't compare it on my end. It's also a cPanel server, performance is mixed. CPU utilization is actually on the low part why memory is more on MySQL.
     
  8. Jonathan

    Jonathan Woohoo Administrator Verified Provider

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    jonspw
    If you have a lot of IMAP boxes don't forget about disk I/O. Do you have hundreds of thousands of emails between all of the IMAP accounts?

    Regardless, email is always a good place to throw in an SSD.
     
    libro22 likes this.
  9. libro22

    libro22 Member

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    No, just a few thousands < 10k per mailbox, averages 2k maybe.

    Yep, I'm now considering that it's more of an I/O issue rather than CPU or memory, will figure out which provider is best for me.
     
  10. norival1992

    norival1992 New Member Verified Provider

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    There's a chance your email could be slow due to warming-up new IPs, ISP spam filters, or how your delivery throttling rules are configured
     
    River likes this.