Install DNS-Only on server with 512 MB of RAM fails. How to force it?

electric

• October 20, 2020 23:42

Hello, I am trying to install cpanel DNS-Only on a small VPS with only 512 MB of RAM. The installer fails with this message: [QUOTE] ( INFO): Checking RAM now... (ERROR): cPanel, L.L.C. requires a minimum of 768 MB of RAM for your operating system. (FATAL): Increase the server's total amount of RAM, and then reinstall cPanel & WHM.
Unfortunately, I am not able to allocate another 256 MB of RAM to this server. I tried using: sh latest-dnsonly --force
But that did not work. This server was previously running DNS-Only on CentOS 6 with 512MB of RAM with no problems. I am just trying to upgrade the server to CentOS 7... The server will be used as a very small nameserver for only a few zones. I will disable MySQL and other non-essential services after the install is finished, as it isn't needed. I'm confident that DNS-Only can run on 512MB since it already was running with no problems.... How can I get past this fatal check? Thanks!

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  ZenHostingTravis

  • October 21, 2020 08:20

  Hi @electric, I believe the ability to override RAM for DNS-Only is a feature request. There does seem to be some older non-cPanel documentation and guides which describes how to override the RAM requirement but I'd just recommend just upgrading.

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  cPanelLauren

  • October 21, 2020 16:37

  While you might be able to customize something, I can't provide you with any cPanel supported solution for this. It's below our system requirements which are there for a reason. I would also not be able to confirm that the server would run successfully on this little RAM.

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  electric

  • October 21, 2020 17:37

  [QUOTE] It's below our system requirements which are there for a reason
  The only reason I can think is that a swapfile will be required. (In our testing, the swapfile does not appear to be used for day-to-day zonefile serving.... it seems to only be used when upcp runs, yum updates, etc. so having a swapfile has very little impact on critical performance of serving DNS zones as fast as possible.) In case anyone is interested, we are running several DNS-Only (v90.0.15) nameserver with only 512MB of RAM and there are no problems at all. (To reduce memory usage, we disabled services not needed in the WHM-->Service Configuration-->Service Manager page: MySQL Server, APNSPush, Eximstats, ModSecLog, RecentAuthedMailIpTracker, and cPBandwd.) Here's one of our DNS-Only server's output from "top" and "free": top - 10:04:43 up 63 days, 8:15, 1 user, load average: 0.04, 0.01, 0.01 Tasks: 41 total, 1 running, 40 sleeping, 0 stopped, 0 zombie %Cpu(s): 1.0 us, 0.3 sy, 0.0 ni, 98.7 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st KiB Mem : 524288 total, 78368 free, 61024 used, 384896 buff/cache KiB Swap: 524288 total, 496176 free, 28112 used. 306142 avail Mem
[root@ns1 ~]# free -h total used free shared buff/cache available Mem: 512M 59M 76M 320K 375M 299M Swap: 512M 27M 484M
  This DNS-Only server handles around 40 zone lookups per second (according to dnstop) using PowerDNS. The VPS is allocated 1 CPU core E5-2620 @ 2GHz (no burst) with 20GB of SSD storage. As long as you're ok with a swapfile being necessary (for upcp, etc.)... there seems to be no problem to have only 512MB of RAM.

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