Re: Cheap NAS
On Thu 20 Oct 2022 at 15:32:20 (+0100), Tixy wrote:
> On Thu, 2022-10-20 at 17:41 +0700, Max Nikulin wrote:
> > On 17/10/2022 22:50, Tixy wrote:
> > > # Set spindown time for disk
> > > if NAS1=`findmnt -n -o SOURCE /nas1/main`; then /sbin/hdparm -S120 $NAS1; fi
> > >
> > > Rather than hard code the disk as /dev/sdc I use 'findmnt' to get the
> > > disk name from the point it's mounted at (/nas1/main in this case).
> >
> > Are there known problems with using e.g. WWN (/dev/disk/by-id/... in
> > /etc/hdparm.conf) for per-disk configuration?
>
> I didn't know of /dev/disk/by-id/wwn-* file or of /etc/hdparm.conf
> until I just googled that, that looks like they would be designed for
> the task. Assuming however that you can rely on udev (?) having already
> created those paths before hdparm is run. (I seem to remember having
> had race conditions related to those paths in the past.)
>From your post, I don't know how you're running hdparm.
But AFAICT, if you run hdparm from udev, you'll see that udev sets up
the symlinks at /lib/udev/rules.d/60-persistent-storage.rules and
runs hdparm at /lib/udev/rules.d/85-hdparm.rules so in this case, you
shouldn't get a race.
> In my case, I spread out wear by rotating disks through different uses:
> main NAS drive, nearline backup mirror of that, and offline backup. So
> I decided rather than mount by UUID or similar, I'd mount by filesystem
> label instead, then I could just relabel the disks when I rotated them.
>
> Of course, having just written that, I realise I don't need findmnt and
> can just use the label in /dev/disk/by-label/ (again, assuming they
> exist in time).
Cheers,
David.
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