# FreeBSD/XEN - Upgrading to 12.0-release-p9 failed: ZFS: i/o error - all block copies unavailable. Also: what is my boot disk?



## Veeny (Aug 11, 2019)

Hi there!

I run a virtual Freebsd box (using XEN) on a cloud server (Gandi). Of course, I have not access to the hypervisor itself.

Yesterday, I tried to upgrade from 12.0-RELEASE-p3 to p9. Failed with the above message. Apparently the zfs boot driver has changed between p3 and p9.
Okay, booted on kernel.old (which is not easy with only a KVM), and then figured out I had to use gpart(1) to upgrade to boot code.
However, I'm faced with a head-scratching conundrum: what is my boot disk and how to access it?

Two ZFS disks are installed on xbd0 and xbd2 with xbd0 being the root disk. However _gpart list_ doesn't want to play with these, and only recognises an xbd25 device, in which it detects two slices:


```
Gandi > gpart show xbd0
gpart: No such geom: xbd0.

Gandi > gpart show xbd25
=>      8  3315696  xbd25  GPT  (1.6G)
        8       56         - free -  (28K)
       64  3295101      1  freebsd-swap  (1.6G)
  3295165        3         - free -  (1.5K)
  3295168    20480      2  ms-basic-data  (10M)
  3315648       56         - free -  (28K)
```

Trying to write a new bootcode on xbd25p1 failed. I mean, gpart worked alright, but the subsequent boot failed with the same error. Where am I supposed to write the new bootloader? The man pages are not very informative.

Thanks a bunch!


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## SirDice (Aug 12, 2019)

Veeny said:


> Trying to write a new bootcode on xbd25p1 failed.


p1 is your freebsd-swap partition. 

You don't appear to have a freebsd-boot partition. Maybe the ms-basic-data partition is actually an efi partition and it boots from there?


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## Veeny (Aug 12, 2019)

SirDice said:


> p1 is your freebsd-swap partition.
> 
> You don't appear to have a freebsd-boot partition. Maybe the ms-basic-data partition is actually an efi partition and it boots from there?


Yeah, I should try. I didn't already because I imagined I had somehow missed something obvious. But since nothing seems to be sticking out, I'll go on with your suggestion. Thanks a lot.


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## Veeny (Aug 16, 2019)

It didn't work. I sent a message to the support team. I hope they will come up with something meaningful.
Thanks again.


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