ZFS confusion

Kaya Saman kayasaman at gmail.com
Mon Jan 27 12:39:31 UTC 2014

On 01/27/2014 12:12 PM, Trond Endrestøl wrote:
> On Mon, 27 Jan 2014 11:42-0000, Kaya Saman wrote:
>> Many thanks everyone (Trond, Dennis, Steve)!!
>> So RAIDz2 or 3 is going to be preferred per the advice given.
>> Now I just need to figure out how to make that work best with my current 5
>> block of disks....  perhaps wait for a while then add some more disks in the
>> mix then create the raidz(x) platform??
>> It would be really good if raidz could be expandable, ie by adding extra 'new'
>> disks into the same vdev.
> It's there!
> Try: zpool attach <pool_name> <existing_member> <new_member1> [new_member2 ...]

Yep, though of course as I'm just testing with temp files currently I 
was unable to make it work:

zpool attach test_pool /tmp/disk1 /tmp/disk6
cannot attach /tmp/disk6 to /tmp/disk1: can only attach to mirrors and 
top-level disks

This is ok though as my block of 5 disks arrive tomorrow with the 
chassis arriving either tomorrow or day after that.

Does 'attaching' create a hybrid raidz2/3 + 1 array or am I confusing again?

Being familiar with raid 1 and 0, I know that the attach command will 
simply mirror a disk:

zpool attach <pool> disk1 disk2

would create a raid1 mirror between the disks... is this the same 
principle or does the command function differently in raidz?

Just checking out the man page gives this:

      zpool attach [-f] pool device new_device

          Attaches new_device to an existing zpool device. The existing 
          cannot be part of a raidz configuration. If device is not 
          part of a mirrored configuration, device automatically transforms
          into a two-way mirror of device and new_device.  If device is 
part of
          a two-way mirror, attaching new_device creates a three-way mirror,
          and so on. In either case, new_device begins to resilver 

-- unless things have been updated since my FBSD version?



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