The third mitigating feature the article forgot to mention is that tmpfs can get paged out to the swap partition. If you drop a large file there and forget it, it will all end up in the swap partition if applications are demanding more memory.
A deep dive into Debian 13 /tmp: What's new, and what to do if you don't like it
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Re: A deep dive into Debian 13 /tmp: What's new, and what to do if you don't like it
#12File is tmpfs will swap out if your system is under memory pressure. If that happens, reading the file back is DRAMATICALLY slower than if you had just stored the file on disk in the first place. This change is not going to speed things up for most users, it will slow things. Instead of caching important files, you waste memory on useless temporary files. Then the system swaps it out, so you can get cache back, and t…
Why is reading the data back from swap be slower at all -- much less "DRAMATICALLY" so -- than saving the data to disk and reading it back?
Re: A deep dive into Debian 13 /tmp: What's new, and what to do if you don't like it
#13File is tmpfs will swap out if your system is under memory pressure. If that happens, reading the file back is DRAMATICALLY slower than if you had just stored the file on disk in the first place. This change is not going to speed things up for most users, it will slow things. Instead of caching important files, you waste memory on useless temporary files. Then the system swaps it out, so you can get cache back, and t…
Most systems probably aren't having problems with insufficient RAM nowaday though, do they? And this will reduce wear on your SSD.
Also, you can easily disable it: https://www.debian.org/releases/trixie/release-notes/issues....
Re: A deep dive into Debian 13 /tmp: What's new, and what to do if you don't like it
#14The third mitigating feature the article forgot to mention is that tmpfs can get paged out to the swap partition. If you drop a large file there and forget it, it will all end up in the swap partition if applications are demanding more memory.
Which is a great reason to have a big swap file now.
Re: A deep dive into Debian 13 /tmp: What's new, and what to do if you don't like it
#15File is tmpfs will swap out if your system is under memory pressure. If that happens, reading the file back is DRAMATICALLY slower than if you had just stored the file on disk in the first place. This change is not going to speed things up for most users, it will slow things. Instead of caching important files, you waste memory on useless temporary files. Then the system swaps it out, so you can get cache back, and t…
Why is reading the data back from swap be slower at all -- much less "DRAMATICALLY" so -- than saving the data to disk and reading it back?
Because swapping back in happens 4kb at a time
Re: A deep dive into Debian 13 /tmp: What's new, and what to do if you don't like it
#16File is tmpfs will swap out if your system is under memory pressure. If that happens, reading the file back is DRAMATICALLY slower than if you had just stored the file on disk in the first place. This change is not going to speed things up for most users, it will slow things. Instead of caching important files, you waste memory on useless temporary files. Then the system swaps it out, so you can get cache back, and t…
Most systems probably aren't having problems with insufficient RAM nowaday though, do they? And this will reduce wear on your SSD. Also, you can easily disable it: https://www.debian.org/releases/trixie/release-notes/issues....
If you're running it in a VM you might not have all that luxurious RAM.
When my Linux VM starts swapping I have to either wait an hour or more to regain control, or just hard restart the VM.
Re: A deep dive into Debian 13 /tmp: What's new, and what to do if you don't like it
#17Using the example from the article, extracting an archive. Surely that use case is entity not possible using in-memory? What happens if you're dealing with a not-unreasonable 100gb archive?
Who runs around with 100gb+ of swap?!
Re: A deep dive into Debian 13 /tmp: What's new, and what to do if you don't like it
#18The third mitigating feature the article forgot to mention is that tmpfs can get paged out to the swap partition. If you drop a large file there and forget it, it will all end up in the swap partition if applications are demanding more memory.
Which is a great reason to have a big swap file now.
Note though that if you don't have swap now, and enable it, you introduce the risk of thrashing [1]
If you have swap already it doesn't matter, but I've encountered enough thrashing that I now disable swap on almost all servers I work with.
It's rare but when it happens the server usually becomes completely unresponsive, so you have to hard reset it. I'd rather that the application trying to use too much memory is killed by the oom manager and I can ssh in and fix that.
[1] https://docs.redhat.com/en/documentation/red_hat_enterprise_...
Re: A deep dive into Debian 13 /tmp: What's new, and what to do if you don't like it
#19The mentioned periodic clean up of tmp files is not enabled out-of-the-box in case of a upgrade from previous Debian versions, see https://www.debian.org/releases/trixie/release-notes/issues.... .
Re: A deep dive into Debian 13 /tmp: What's new, and what to do if you don't like it
#20Why this change? Writing to it will be faster than disk but idk if am is a precious commodity I’d rather it was just a part of the disk I was writing to.