[CentOS] reboot - is there a timeout on filesystem flush?

[Les Mikesell]

On Tue, Jan 6, 2015 at 6:37 PM, Gary Greene <ggreene at minervanetworks.com> wrote:
>
>
> Almost every controller and drive out there now lies about what is and isn’t flushed to disk, making it nigh on impossible for the Kernel to reliably know 100% of the time that the data HAS been flushed to disk. This is part of the reason why it is always a Good Idea™ to have some sort of pause in the shut down to ensure that it IS flushed.
>
> This is also why server grade gear uses battery backed buffers, etc. which are supposed to allow drives to properly flush the data to disk. There is still a slim chance in these cases that the data still will not reach the platter before power off or reboot, especially in catastrophic cases.
>

This was a reboot from software, not a power drop.  Does that do
something to kill the disk cache if anything happened to still be
there?

-- 
   Les Mikesell
      lesmikesell at gmail.com