On 2017-11-13 09:56, Gene Heskett wrote:
On Monday 13 November 2017 07:19:45 Austin S. Hemmelgarn wrote:
On 2017-11-11 01:49, Jon LaBadie wrote:
Just a thought. My amanda server has seven hard drives
dedicated to saving amanda data. Only 2 are typically
used (holding and one vtape drive) during an amdump run.
Even then, the usage is only for about 3 hours.
So there is a lot of electricity and disk drive wear for
inactive drives.
Can todays drives be unmounted and powered down then
when needed, powered up and mounted again?
I'm not talking about system hibernation, the system
and its other drives still need to be active.
Back when 300GB was a big drive I had 2 of them in
external USB housings. They shut themselves down
on inactivity. When later accessed, there would
be about 5-10 seconds delay while the drive spun
up and things proceeded normally.
That would be a fine arrangement now if it could
be mimiced.
Aside from what Stefan mentioned (using hdparam to set the standby
timeout, check the man page for hdparam as the numbers are not exactly
sensible), you may consider looking into auto-mounting each of the
drives, as that can help eliminate things that would keep the drives
on-line (or make it more obvious that something is still using them).
I've investigated that, and I have amanda wrapped up in a script that
could do that, but ran into a showstopper I've long since forgotten
about. Al this was back in the time I was writing that wrapper, years
ago now. One of the show stoppers AIR was the fact that only root can
mount and unmount a drive, and my script runs as amanda.
While such a wrapper might work if you use sudo inside it (you can
configure sudo to allow root to run things as the amanda user without
needing a password, then run the wrapper as root), what I was trying to
refer to in a system-agnostic manner (since the exact mechanism is
different between different UNIX derivatives) was on-demand
auto-mounting, as provided by autofs on Linux or the auto-mount daemon
(amd) on BSD. When doing on-demand auto-mounting, you don't need a
wrapper at all, as the access attempt will trigger the mount, and then
the mount will time out after some period of inactivity and be unmounted
again. It's mostly used for network resources (possibly with special
auto-lookup mechanisms), as certain protocols (NFS in particular) tend
to have issues if the server goes down while a share is mounted
remotely, even if nothing is happening on that share, but it works just
as well for auto-mounting of local fixed or removable volumes that
aren't needed all the time (I use it for a handful of things on my
personal systems to minimize idle resource usage).
