On 16/06/2012 03:43, Serge wrote: > 2012/6/15 Jean-Christophe Dubacq wrote: > >>>> This is often seen as not a good move to have a user-writable directory >>>> on the system partition(s), since this provides for easy DOS >>> >>> DoS like what? /tmp on disk have a 5% safety limit available for system, >>> user can "DoS" only his own processes, and he can do that anyway. But >>> /tmp on tmpfs is even worse move, since it does not have 5% safety. >> >> 1) With 2TB disks, I certainly do not use 5% any more > > How is that? Isn't it a default value for 2TB disks any more? Or you mean > that you manually reduced it to e.g. 1%? Yes. That's the thing I do on most partitions (large ones). >> 2) Mysql, apache, postfix, all kind of vital systems, do not run as >> root. And if /tmp is full (and mounted on /), / is full (and so is >> /var). All kind of mayhem may happen there (I have seen it). > > You talk about mysql/apache/postfix, so I assume you mean a server. > And since it's about users filling /tmp I assume it's a multiuser server > (or rather at-least-one-user server). Then putting /tmp on tmpfs is a bad > idea there, because doing that will force users to use /var/tmp for large > files and will (not "can", but "will", since /var/tmp is not cleaned) > eventually fill /var partition, which is exactly what you need to prevent. Strangely enough, most users do not seem to know about /var/tmp. So, when they put large files, they tend to do that in (IMO better) other places: * $HOME/Desktop * $HOME * $HOME/Downloads * $HOME/theplaceIamworking which is better in terms of system management (except that it is also on NFS, and they suffer terrible pain because of that). Sincerly, -- Jean-Christophe Dubacq
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