Mirror pool drives keep reverting to HFS

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Mirror pool drives keep reverting to HFS

Postby Sharko » Sat Aug 04, 2018 9:30 am

So, this has happened twice now: I create a mirror pool, export it, shut down the external dual disk enclosure, restart the external dual disk enclosure... and the HFS disks come back and show up on the desktop (and, obviously, I can't import the pool any longer). Here is the annotated terminal session, it's very simple:

Code: Select all
sh-3.2# zpool import ELITE
cannot import 'ELITE': no such pool available

<I see two HFS volumes on the desktop, so I eject them and create a new pool with the command below>

sh-3.2# zpool create -f -o ashift=12 -O casesensitivity=insensitive -O normalization=formD ELITE  mirror disk11s2 disk10s2
sh-3.2# zpool export ELITE
Running process: '/usr/sbin/diskutil' 'unmount' '/Volumes/ELITE'
Unmount successful for /Volumes/ELITE
sh-3.2#

<I power off the external enclosure>
<I power on the external enclosure>
<the two HFS disks show up again>
 


Details: running 1.7.2 zfs under El Capitan 10.11.6, up to date with all security patches. Other World Computing dual disk Elite enclosure set up as JBOD. Two 4 TB disks. Connected via the ESATA interface. Any suggestions on what I'm doing wrong?

DiskUtilityEliteDisk.jpg
Screenshot of disk utiility showing one of the disks.
DiskUtilityEliteDisk.jpg (49.49 KiB) Viewed 367 times
Sharko
 
Posts: 70
Joined: Thu May 12, 2016 12:19 pm

Re: Mirror pool drives keep reverting to HFS

Postby tangles » Sun Aug 05, 2018 3:58 am

Assuming you don't want to use these two disks with any other filesystem, don't create your pool using slices…

The "s2" bit on the end of disk11s2 is probably what's causing it… I never do this...

Remove the s2 and give the whole disk to ZFS.

Also, to prepare your drives:
Code: Select all
sudo umountDisk force /dev/diskn ; sudo dd if=/dev/zero of=/dev/rdiskn bs=1024 count=5120000

where "n" is the disk in question.

then go create your pool.
Last edited by tangles on Mon Aug 06, 2018 4:18 am, edited 1 time in total.
tangles
 
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Re: Mirror pool drives keep reverting to HFS

Postby Sharko » Sun Aug 05, 2018 7:37 pm

tangles, thanks for the response. I can try getting rid of the slices. However, I don't understand the purpose of the dd command you listed; it looks like it is simply doing a buffered read from disk n to a raw write of disk n, the same disk... what is the purpose of that? I could understand it if you were suggesting to use dd to obliterate the lowest blocks of the disk, but I don't think that is what you're suggesting here, or is it?

By the way, the slices were just the remnant of my earlier attempt to create an encrypted mirrored pool using the Filevault method earlier. They were HFS partitions that were originally Filevault encrypted, and when I blew that away I just tried using the slices.
Sharko
 
Posts: 70
Joined: Thu May 12, 2016 12:19 pm

Re: Mirror pool drives keep reverting to HFS

Postby tangles » Mon Aug 06, 2018 4:19 am

my bad,
changed it to /dev/zero
now it should make sense…
it's just a command to write zeros at the start of the disk to wipe out any trace of existing partition maps etc.
tangles
 
Posts: 133
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