[Discuss] ZFS for an Encrypted External Disk: My Experience and Notes

[dsr at randomstring.org (Dan Ritter)]

Rich Pieri wrote: 
> On Wed, 27 Jul 2022 16:13:31 -0400
> markw at mohawksoft.com wrote:
> 
> > A stripe over two mirrors is not as reliable as RAID6. If you have 4
> > drives arranged in two mirrors, each mirror can only survive the loss
> > of one drive. So, your system, if it loses 2 drives, has a 33.33%
> > chance of losing half its data.
> 
> If I cared that much about fault tolerance then I'd be running one
> 4-way mirror instead of two 2-way mirrors. As is, if I lose two drives
> out of the four before I can replace and resilver one, all I'm really
> out is the most recent backups of my daily drivers and the time needed
> to restore my backups which are kept on auxiliary storage.

I'm starting to think that an optimal desktop arrangement might be:

NVMe SSD with ZFS on root, zpool 1.
SATA SSD in a second zpool, used only to receive ZFS from the other disk.

The NVMe is fast and relatively expensive, but if it dies, you
still have a pretty fast copy from a few hours ago, which has
had much less written to it and will thus have a longer
lifetime.

-dsr-