[BUGS] ZFS dis-integration

[Jan Mikkelsen]

Hi,

On 11/07/2010, at 3:42 AM, Andrew Sinclair wrote:

> it was either this, or be at the mercy of ZFS. If you do not limit
> yourself to just one aggregated drive interface, ZFS will complain
> when disks are reattached in the incorrect order. I have already tried
> multiple independent devices and ZFS has no way that I can see, to
> safely change device without a complete resilver. I just happened to
> be lucky that USB devices are numbered sequentially; not expecting end
> users to know this.

I glabel all the bare drives and then create zfs pools using the glabel names rather than the raw devices.  That way the underlying device name doesn't matter and you can move the drives around, add drives that change the device numbering, etc.

>>> and yes, I keep backups but upgrading is a pain as it is, with all the
>>> manual diff/merges one is required to do. If I were not stonewalled
>>> out of my own trade, I'd contribute a Subversion based /etc in the
>>> base install, at my own expense, with pleasure.
>> 
>> Can you explain more about how your proposed approach is an improvement
>> over mergemaster?  The underlying issue is that /etc contains files
>> with content depends on both the version of FreeBSD and the specific
>> host configuration.  Therefore any solution needs to support 3-way
>> merging - which is messy.

My approach to this problem is have a read-only /etc and then union mount a /cfg/etc filesystem for local changes. Some scripts to merge the system accounts and local accounts and you never need run mergemaster again.

That also simplifies upgrades: Have two partitions with all the "system stuff", to do an upgrade update the non-running partition, switch partitions and reboot. Quick, /etc changes are merged, and there is a simple rollback procedure.

Jan.