[HEADS-UP] Rawhide: /tmp is now on tmpfs

Chris Adams cmadams at hiwaay.net
Wed Jun 20 17:55:40 UTC 2012


Once upon a time, Brian Wheeler <bdwheele at indiana.edu> said:
> So, how does this scenario work?
> 
> * The machine has 4G of RAM,
> * > 50% RAM is being used by actual software (firefox, eclipse, mail 
> client, etc), so the other < 50% is pagecache
> * The machine has 4G of swap, none of which is active.
> 
> So then a user drops a 8.5G DVD image into /tmp.
> 
> On a traditional /tmp-on-disk if it filled up then you'd get an ENOSPC 
> and user things can't write to disk, but the OS will be fine since 5% is 
> reserved for root.
> 
> With tmpfs the pagecache will fill up and start to overflow to 
> swap...until swap fills up. What happens then?

2G gets written and then -ENOSPC.  2G gets pushed to swap.

The default for tmpfs mounts is an fs that is sized to RAM/2.

-- 
Chris Adams <cmadams at hiwaay.net>
Systems and Network Administrator - HiWAAY Internet Services
I don't speak for anybody but myself - that's enough trouble.


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