# glabel messages about secondary GPT header



## Tsuroerusu (Apr 12, 2011)

I have recently turned my former workstation into a ZFS-based storage server. I have FreeBSD installed on a ZFS mirror on two 250 GB drives with the AHCI driver loaded. Both drives are labeled using glabel (ada0 is labeled as _disk01_ and ada1 is labeled as _disk02_).

The drives are GPT partitioned, I followed this guide with regard to the partitioning:
http://www.wirednoize.net/freebsd/index.php?FreeBSD 8.2 Release amd64 pure ZFS install

The zpool consists of disk01p2 and disk02p2.

The labels work fine, and the system seems fine.

When the system boots, and when certain commands relating to the disks are run (Last time I saw this was when I did a _zpool scrub_) I see the following message:


```
GEOM: ada0: the secondary GPT header is not in the last LBA.
GEOM: ada1: the secondary GPT header is not in the last LBA.
```

I have done the installation several times over because I wanted to get a good feel for it, this final time I used glabel as well, and as I would expect, the disk size reported by _gpart show_ was "one" (Not sure what the unit was) less when showing label/disk01 than ada0.

I found the following article written in Russian: http://bu7cher.blogspot.com/2011/03/freebsd-gmirror-gpt-ufs.html
I read it using Google Translate and it seems to indicate that the above is more or a less a safe mismatch as far as I can tell, however not something I wanna rely on (Google Translate is definitely not perfect) ...

Therefore, my question is, can I safely ignore this note from GEOM?


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## butcher (Apr 14, 2011)

It depends on what displays *gpart show* on your system. You can ignore these messages if you use GPT that was created on label/disk01 and label/disk02.


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## Tsuroerusu (Apr 14, 2011)

This is what *gpart show* shows:


```
sol# gpart show
=>       34  490350604  label/disk01  GPT  (234G)
         34        128             1  freebsd-boot  (64K)
        162  490350476             2  freebsd-zfs  (234G)

=>       34  490350604  label/disk02  GPT  (234G)
         34        128             1  freebsd-boot  (64K)
        162  490350476             2  freebsd-zfs  (234G)
```


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## butcher (Apr 14, 2011)

It seems good. You should keep in mind that your backup GPT header is not in the last LBA and it is enough to have partition table backup to be able recover it. You can create backup with *gpart backup* command.


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## Tsuroerusu (Apr 14, 2011)

butcher said:
			
		

> It seems good. You should keep in mind that your backup GPT header is not in the last LBA and it is enough to have partition table backup to be able recover it. You can create backup with `gpart backup` command.



Awesome, thanks a lot, I appreciate it! :e


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