RFC: Suggesting ZFS "best practices" in FreeBSD

[Borja Marcos]

On Jan 23, 2013, at 3:30 PM, Ollivier Robert wrote:

> According to Freddie Cash on Tue, Jan 22, 2013 at 03:02:40PM -0800:
>> The ZFS metadata on disk allows you to move disks around in a system and
>> still import the pool, correct.
> 
> Even better, a few years ago before I enabled AHCI on my machine, the
> drives were named adX.  After I started using AHCI, the drives became adaY
> and it still booted fine.

Yes, that's right. As an example, yesterday I used the gnop kludge to have a SSD recognized as a 4K-sector drive. After a reboot, 
ZFS was able to locate the device even though the named gnop device had disappeared.

However, remember that the Murphy's field is enormously intense around anything that holds data, especially
if that data is important. Yes, it works, but it's better not to rely too much on error recovery mechanisms. And there is
at least one situation in which the dynamic renumbering causes trouble (failure + reboot) which is not so rare on 
high uptime machines with many disks.



Borja.