Upgrade to 9.0: How to convert zpool from adX to adaX?

[Martin Birgmeier]

On 01/05/12 10:35, Volodymyr Kostyrko wrote:
> 05.01.2012 09:59, Martin Birgmeier wrote:
>> In 9.0, if I keep kern.cam.ada.legacy_aliases=1, there will be two paths
>> to each device, one through adX, the other through adaX. Which one will
>> zfs use, and show with 'zpool status'?
>
> You are partially incorrect here:
> [torn] ~> ls -la /dev | grep ad
> lrwxr-xr-x   1 root  wheel            4  5 jan 08:22 ad6@ -> ada0
> lrwxr-xr-x   1 root  wheel            5  5 jan 08:22 ad6a@ -> ada0a
> lrwxr-xr-x   1 root  wheel            5  5 jan 08:22 ad6b@ -> ada0b
> lrwxr-xr-x   1 root  wheel            5  5 jan 08:22 ad6d@ -> ada0d
> lrwxr-xr-x   1 root  wheel            5  5 jan 08:22 ad6e@ -> ada0e
> lrwxr-xr-x   1 root  wheel            5  5 jan 08:22 ad6f@ -> ada0f
> lrwxr-xr-x   1 root  wheel           13  5 jan 08:22 ad6f.journal@ -> 
> ada0f.journal
> crw-r-----   1 root  operator    0,  64  5 jan 08:22 ada0
> crw-r-----   1 root  operator    0,  66  5 jan 08:23 ada0a
> crw-r-----   1 root  operator    0,  68  5 jan 08:22 ada0b
> crw-r-----   1 root  operator    0,  70  5 jan 08:23 ada0d
> crw-r-----   1 root  operator    0,  72  5 jan 08:23 ada0e
> crw-r-----   1 root  operator    0,  74  5 jan 08:22 ada0f
> crw-r-----   1 root  operator    0,  79  5 jan 08:23 ada0f.journal
>
>> Also, I understand that I will have to wire down the various ATA CAMs to
>> obtain the old numbering. How can I do this? Again, which path would zfs
>> use if I did not wire down the ATA CAMs? Will I have half of my devices
>> go through adX and the other through adaX, or will zfs even believe that
>> it has a multipath connectivity to each device?
>
> Not at all, ad6 would be a symlink to correct ada device, I haven't 
> yet changed the fstab on this machine and it reads:
>
> # Device                Mountpoint      FStype  Options         Dump 
> Pass#
> /dev/ad6b               none            swap    sw              0       0
> /dev/ad6a               /               ufs     rw              1       1
> /dev/ad6e               /tmp            ufs     rw              2       2
> /dev/ad6f.journal               /usr            ufs     rw,async 
>         2       2
> /dev/ad6d               /var            ufs     rw              2       2
> /dev/cd0                /cdrom          cd9660  ro,noauto       0       0
>
Sigh... I get only half the answers, and these are not so helpful either.

First of all, I *am* correct in saying that there are two paths to the 
same device, because the purpose of a (sym-)link precisely is to have an 
alternate path to the same object in the filesystem. So if someone tells 
me that zfs somehow (how?) excludes devices reached through symlinks, 
*that* would be an information I would find useful.

Second, the whole purpose of the kern.cam.ada.legacy_aliases is to have 
backwards compatibility for fstab etc by installing symlinks in /dev. I 
know this very well but want to prepare for the day when I want to get 
rid of the necessity for this compatibility.

Third, I have now asked twice how to wire the ATA CAM devices, without 
anybody even referring to that question. Well, I guess I'll have to find 
that out myself.

I do appreciate all answers, even more so as I perfectly understand they 
are *free* answers, and maybe the above is even helpful to someone else 
(and does not confuse them instead), but I'd appreciate it even more if 
they were real answers.

Regards,

Martin