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804 points jryio | 2 comments | | HN request time: 0.63s | source
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speedgoose ◴[] No.45661785[source]
Looking at the htop screenshot, I notice the lack of swap. You may want to enable earlyoom, so your whole server doesn't go down when a service goes bananas. The Linux Kernel OOM killer is often a bit too late to trigger.

You can also enable zram to compress ram, so you can over-provision like the pros'. A lot of long-running software leaks memory that compresses pretty well.

Here is how I do it on my Hetzner bare-metal servers using Ansible: https://gist.github.com/fungiboletus/794a265cc186e79cd5eb2fe... It also works on VMs.

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awesome_dude ◴[] No.45662628[source]
How do you get swap on a VPS?
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justsomehnguy ◴[] No.45663111[source]
Search "linux enable swap in a file"

    To enable a swap file in Linux, first create the swap file using a command like sudo dd if=/dev/zero of=/swapfile bs=1G count=1 for a 1GB file. Then, set it up with sudo mkswap /swapfile and activate it using sudo swapon /swapfile. To make it permanent, add /swapfile swap swap defaults 0 0 to your /etc/fstab file.
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collinmanderson ◴[] No.45663334[source]
Yes. I think might also need to chmod 600 /swapfile. I do this on all my VPS, especially helps for small VPS with only 1GB ram:

   fallocate -l 1G /swapfile
   chmod 600 /swapfile
   mkswap /swapfile
   swapon /swapfile
Works really well with no problems that I've seen. Really helps give a bit more of a buffer before applications get killed. Like others have said, with SSD the performance hit isn't too bad.
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1. awesome_dude ◴[] No.45664144[source]
IME SWAP has been explicitly disabled by the VPS providers.

Partly it's a money thing (they want to sell you RAM), partly it's so that the shared disk isn't getting thrashed by multiple VPS

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2. efreak ◴[] No.45666094[source]
Get better VPS then. Openvz and other kernel paravirtualization have limits, go for Xen or KVM instead (Xen has paravirtualization as well, but I'm not sure how much it's actually used). Full virtualization (implemented by Xen and KVM) do not allow you to prevent swap from being used.