A seperate ZFS question

Paul Macdonald paul at ifdnrg.com
Fri Apr 28 21:19:39 UTC 2017

On 28/04/2017 15:51, Steve O'Hara-Smith wrote:
> On Fri, 28 Apr 2017 15:52:59 +0200 (CEST)
> Trond Endrestøl <Trond.Endrestol at fagskolen.gjovik.no> wrote:
>> On Fri, 28 Apr 2017 14:14+0100, Paul Macdonald wrote:
>>> I fat fingered adding a cache drive and was unable to remove the SSD
>>> cache drive (ada2)
>> First, you have gpt/zfs0 and ada1p3 in a mirrored configuration. Next,
>> you have ada2 striped (RAID 0) to the first pair of mirrors. This is a
>> very weird "RAID 1 + 0" combo. Guess what will happen when you lose
>> ada2!
>> Maybe you should describe what you wanted to happen in the first
>> place.
> 	He did, ada2 is supposed to be a cache drive, now it's a stripe.
>> I suggest you make good backups of this pool, destroy it, recreate it
>> properly, and restore the missing data.
> 	Agreed, you can't undo adding a stripe.

all this so far i knew,

It's an entirely unwanted config, and i'll likely just migrate either 
the data or the jails to another box, but  i'd hoped to understand what 
the config  meant under ZFS:

As i understand from comments,  i have effectively created a mis-sized 
RAID0 (stripe) between a SATA mirror set and a single SSD,

i'm now very glad i didn't just unplug the SSD drive and instead added a 
2nd SSD  for the actual cache

So i guess i have until the SSD fails (or presumably until the SSD 
reaches its capacity to fix this)

thanks to all for the comments/guidance


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