On Jul 30, 2012, at 12:25 PM, Tim Cook wrote:
> On Mon, Jul 30, 2012 at 12:44 PM, Richard Elling <richard.ell...@gmail.com> 
> wrote:
> On Jul 30, 2012, at 10:20 AM, Roy Sigurd Karlsbakk wrote:
>> ----- Opprinnelig melding -----
>>> On Mon, Jul 30, 2012 at 9:38 AM, Roy Sigurd Karlsbakk
>>> <r...@karlsbakk.net> wrote:
>>>>>> Also keep in mind that if you have an SLOG (ZIL on a separate
>>>>>> device), and then lose this SLOG (disk crash etc), you will
>>>>>> probably
>>>>>> lose the pool. So if you want/need SLOG, you probably want two of
>>>>>> them in a mirror…
>>>>> That's only true on older versions of ZFS. ZFSv19 (or 20?) includes
>>>>> the ability to import a pool with a failed/missing log device. You
>>>>> lose any data that is in the log and not in the pool, but the pool
>>>>> is
>>>>> importable.
>>>> Are you sure? I booted this v28 pool a couple of months back, and
>>>> found it didn't recognize its pool, apparently because of a missing
>>>> SLOG. It turned out the cache shelf was disconnected, after
>>>> re-connecting it, things worked as planned. I didn't try to force a
>>>> new import, though, but it didn't boot up normally, and told me it
>>>> couldn't import its pool due to lack of SLOG devices.
>>> Positive. :) I tested it with ZFSv28 on FreeBSD 9-STABLE a month or
>>> two ago. See the updated man page for zpool, especially the bit about
>>> "import -m". :)
>> On 151a2, man page just says 'use this or that mountpoint' with import -m, 
>> but the fact was zpool refused to import the pool at boot when 2 SLOG 
>> devices (mirrored) and 10 L2ARC devices were offline. Should OI/Illumos be 
>> able to boot cleanly without manual action with the SLOG devices gone?
> No. Missing slogs is a potential data-loss condition. Importing the pool 
> without
> slogs requires acceptance of the data-loss -- human interaction.
>  -- richard
> --
> ZFS Performance and Training
> richard.ell...@richardelling.com
> +1-760-896-4422
> I would think a flag to allow you to automatically continue with a disclaimer 
> might be warranted (default behavior obviously requiring human input). 

Disagree, the appropriate action is to boot as far as possible.
The pool will not be imported and will have the normal fault management
alerts generated.

For interactive use, the import will fail, and you can add the -m option.
 -- richard

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