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0 pointswtallis0y ago0 comments

CI containers should probably run entirely from tmpfs.

0 comments

Can tmpfs be backed by persistent storage? Most of the recent stuff I've worked on is a little too big to fit in memory handily. Ideally about 20GiB of scratch space for 4-8GiB of working memory would be ideal.

I've had good success with machines that have NVMe storage (especially on cloud providers) but you still are paying the cost of fsync there even if it's a lot faster

wtallisOP0y ago

tmpfs is backed by swap space, in the sense that it will overflow to use swap capacity but will not become persistent (since the lack of persistence is a feature).

candiddevmike0y ago

We built EtchaOS for this use case--small, immutable, in memory variants of Fedora, Debian, Ubuntu, etc bundled with Docker. It makes a great CI runner for GitHub Actions, and plays nicely with caching:

https://etcha.dev/etchaos/

jacobwg0y ago

We're having some success with doing this at the block level (e.g. in-memory writeback cache).

yjftsjthsd-h0y ago

Why do it at the block level (instead of tmpfs)? Or do you mean that you're doing actual real persistent disks that just have a lot of cache sitting in front of them?

jacobwg0y ago

The block level has two advantages: (1) you can accelerate access to everything on the whole disk (like even OS packages) and (2) everything appears as one device to the OS, meaning that build tools that want to do things like hardlink files in global caches still work without any issue.

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nijave0y ago

I've had good success with machines that have NVMe storage (especially on cloud providers) but you still are paying the cost of fsync there even if it's a lot faster

wtallisOP0y ago

tmpfs is backed by swap space, in the sense that it will overflow to use swap capacity but will not become persistent (since the lack of persistence is a feature).

candiddevmike0y ago

https://etcha.dev/etchaos/

jacobwg0y ago

We're having some success with doing this at the block level (e.g. in-memory writeback cache).

yjftsjthsd-h0y ago

Why do it at the block level (instead of tmpfs)? Or do you mean that you're doing actual real persistent disks that just have a lot of cache sitting in front of them?

jacobwg0y ago

j / k navigate · click thread line to collapse