[mythtv-users] Manage recording storage group with btrfs subvolume

[David Hampton]

On Sun, 2021-01-10 at 19:21 +0800, James Linder wrote:
> 
> 
> > On 10 Jan 2021, at 6:06 pm, Mike Perkins <
> > mikep at randomtraveller.org.uk> wrote:
> > 
> > On 10/01/2021 02:27, Richard Shaw wrote:
> > > I'm looking at moving to a 4 drive raid1 array (and perhaps
> > > converting to
> > > raid5 later) btrfs array. Most of the space will be used for
> > > media but I
> > > want to keep 1TB for recordings.
> > > The problem is that btrfs will share free space among subvolumes
> > > by default
> > > and I don't know if there is  a quota method that will limit free
> > > space
> > > reporting so that the backend will expire recordings properly
> > > like on a
> > > dedicated filesystem.
> > > Anyone else run into this and have a solution?
> > I run my "raid" volumes under LVM. That way I can allocate discrete
> > volumes[1] to each function and the free space is not shared
> > between them.
> > 
> > [1] Each volume can them be formatted a different way as required.
> 
> Richard why would you not partiton your disks *exactly* as you want,
> rather than what your vendor (suse ??) decided what was good for most
> people. When I looked I decided that btrfs was not what I wanted on
> my myth server

For an opposite viewpoint, I've been running a four drive btrfs raid-6
setup for about a decade as my recordings storage volume, and have been
very happy with it. I only have the one subvolume though, so I've never
looked at the quota support.

David