freebsd-questions Digest, Vol 531, Issue 6

[Scott Bennett]

     On Thu, 7 Aug 2014 10:33:09 +0200 (CEST) Trond Endrest?l
<Trond.Endrestol at fagskolen.gjovik.no> wrote:
>On Thu, 7 Aug 2014 03:16-0500, Scott Bennett wrote:
>>      On Wed, 6 Aug 2014 03:49:37 -0500 Andrew Berg
>> <aberg010 at my.hennepintech.edu> wrote:
>> >On 2014.08.06 02:32, Scott Bennett wrote:
>> >>
>> >> [much deleted  --SB]
>> >>
>> >> 	2) How does one start or stop a pool?
>> >That depends on what you mean by 'start' and 'stop'. I am guessing by what you
>> >described that you mean 'import' and 'export'. I'm not sure how to prevent
>> 
>>      Oh.  Okay.  At least there is some way to accomplish the same thing.
>> 
>> >automatic import for pools that were imported on the same system and not
>> >exported prior to shutdown, but I am sure it can be done. Resilvering does not
>> 
>>      Maybe someone else will say how it can be done.
>> 
>> >mercilessly thrash disks; standard reads and writes are given higher priority
>> >in the scheduler than resilver and scrub operations.
>> 
>>      If two pools use different partitions on a drive and both pools are
>> rebuilding those partitions at the same time, then how could ZFS *not*
>> be hammering the drive?
>
>Why would you place multiple pools on the very same drives?

     Because I need about 1/4 of my usable data space on those drives
to be encrypted and the other 3/4 to be unencrypted, I need (according
to another respondent) to build my raidzN pool from .eli components
and the rest from unencrypted components.
>
>The only real world example I can think of is having separately 
>mirrored boot and root pools using the same drives.

     See above.
>
>E.g., bootpool using ada0p2 and ada1p2 as its mirrors, and rootpool 
>using adap0p3 and ada1p3 as its mirrors, with ada0p1 and ada1p1 being 
>the gpt boot partitions, and possibly with swap partitions on ada0p4 
>and ada1p4.
>
     Those low-space-requiring uses are also good examples of why a
multiterabyte drive might need to be divided into different partitions
with only some of them dedicated to ZFS.  I had hoped to put some small
partitions in between the large ones for other uses, too.


                                  Scott Bennett, Comm. ASMELG, CFIAG
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