On 06/20/2012 01:55 PM, Chris Adams wrote:
Once upon a time, Brian Wheeler <bdwheele(a)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.
So the default is that I can use 2G in /tmp regardless of how much swap
is present if the system memory size is 4G? So the only way to get more
/tmp is to either mess with the max% or buy more ram?