Linux Ate My RAM (opens in new tab)

(linuxatemyram.com)

3 pointsIA215y ago5 comments

5 comments

4 comments · 1 top-level

joshspankit5y ago· 3 in thread

> The only reason anyone ever wants to disable disk caching is because they think it takes memory away from their applications, which it doesn't!

Wildly disagree!

I regularly want to disable disk caching when I want to be able to drop power or disconnect a drive without drive corruption.

With smaller “microcontrollers” running linux, their power could drop at any moment. With external drives, I might want to pull the drive the second it’s done transferring a file. Caches get in the way in both cases.

IcePic5y ago

There are different types, which I think is buffers vs cache in top. The read caches would be fine but the delayed writes in ram are quite another thing.

The one that eats your ram (the reason for the site to exist) would mostly be the read caches.

Out_of_Characte5y ago

enabling or disabling disk cache doesn't prevent the write hole when experiencing sudden power loss. in transit writes are still lost and have to be atomically accounted for. disk caches only increase the amount of data that is or isn't synced with disk.

joshspankit5y ago

With sudden power loss, the difference is that any single write may be in the cache for longer than the time it would have taken to write it. In the case of no cache with a power loss there is only a single possible failure: power loss during write. With cache that expands to two possible failures: Power loss during write from cache, and power loss with unwritten data in the cache.

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