[Mageia-discuss] File systems ?

Mon Jun 4 12:39:18 CEST 2012

> On Friday 01 Jun 2012 17:22 my mailbox was graced by a message from David
+> W.
+> Hodgins who wrote:
+>> > I run a script based on df to check the total HD use on my box.
+>> > After installing Mageia 2 it gives impossible results, which I
+>> attribute
+>> > to DF now showing filesystems which I cannot find referenced in the
+>> File
+>> > Hierarchy Standard, like rootfs, devtmpfs or (several) tmpfs (mounted
+>> in
+>> > separate locations).
+>
+>> They are tmpfs filesystems, which by definition means they exist in ram
+>> only.
+>
+> I wonder how they can exist in RAM given the total size of the tmpfs
+> partitions is almost double the installed RAM of the computer.
+
+tmpfs partitions are always shared in memory, they only use in memory what
+is used. the available size is actually the maximum tmpfs partitions (in
+total) can allocate from memory (and standard this is 50% of RAM).
+
+this has been so for as long as tmpfs exists, which is decades really.
+
+cgroup is a new kernel feature that allows grouping of processes (Control
+Groups), killing the control group will kill all the processes in the
+group. and it can be used to set process limits for the whole group.
+