46 lines
1.4 KiB
Markdown
46 lines
1.4 KiB
Markdown
---
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title: When life gives you temp space - make lemonade !
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date: 2015-09-02 20:00:24
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tags: [cloud, azure, linux]
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---
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Some VPS providers, e.g. Azure provide you with 2 disk drives for
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your VPSes. One, of very limited size, system disk, and the other one,
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spacy but with not guarantees that the data survives reboot. Basically
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it means that you can have a small VPS, with a small amount of RAM but
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large temp disk space. Why this could be useful ? Imagine tasks with
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lots of mem requirements but that not need to be extra fast, where
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swapping is allowed. Like complex nightly builds. Here is a set of super
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simple scripts I've come up with to quickly boot up a system, and then
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in the background add a new swap file on the temp drive there. The temp
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drive is assumed to be under /mnt.
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```
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root@someazurehost:~# cat /etc/rc.local
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#!/bin/sh -e
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set -v
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# do not wait for swap to become online,
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# proceed with the boot further,
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# with swap being created in the background
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/etc/make_and_enable_swap &
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exit 0
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```
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```
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root@someazurehost:~# cat /etc/make_and_enable_swap
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#!/bin/sh
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set -e
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set -v
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# create new 2GB swap file
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dd if=/dev/zero of=/mnt/swap bs=1M count=2048
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chmod 0600 /mnt/swap
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mkswap /mnt/swap
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swapon /mnt/swap
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```
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Don't forget to make `/etc/make_and_enable_swap` executable !
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Do not add this swap file to fstab, as it is being read before rc.local,
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and this may certainly result in a boot failure, as the swap file would
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not be ready yet.
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