Bug 204976 - zfs root fails to boot raidz1 raidz2 raidz3
Summary: zfs root fails to boot raidz1 raidz2 raidz3
Status: Open
Alias: None
Product: Base System
Classification: Unclassified
Component: kern (show other bugs)
Version: CURRENT
Hardware: Any Any
: --- Affects Many People
Assignee: freebsd-fs
Keywords: needs-qa
Depends on:
Reported: 2015-12-02 21:05 UTC by mikhail.rokhin
Modified: 2016-07-10 15:51 UTC (History)
3 users (show)

See Also:


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Description mikhail.rokhin 2015-12-02 21:05:32 UTC
RAIDZ1 failure:

FreeBSD/x86 boot
Default: zroot/ROOT/default:/boot/kernel/kernel
boot: ZFS: i/o error - all block copies unavailable
Invalid format

Can't find /boot/kernel/kernel

RAIDZ2 failure:

No. Boots fine.

RAIDZ3 failure:

No. Boots fine.

Stripe & Mirroring boot fine.

There's some error when changing from RAIDZx to Mirroring and choosing 2 disks - autoZFS fails to partition. Probably ZFS-sys counts all existing disk and fails due to uncleared disks left, misunderstanding 2 chosen and cleared vs. left with uncleared zroot from previous RAIDZx partitioning. So it turns out that ZFS counts & reads all disks, whatever quantity chosen in menu. It's failure misbehaviour. 

5x 16Gb disks via SAS lsilogic.

i386 - the same RAIDZ1 failure. ZFS shows very low speed (amd64 1000-5000 files/sec, i386 50-100 files/sec).

But three disks RAIDZ1 boots fine, 4 disks - boots fine.

Why do 5 or 9 or more disks lead to failure then?

RAIDZ2 and RAIDZ3 fails to boot when chosen 11 disks.
Comment 1 Fabian Keil 2015-12-04 13:51:38 UTC
I'm not sure I understand you correctly, but I would not expect
the installer to modify devices that weren't selected as install

I also would not expect the system to boot reliably if some
of the disks (that were not modified during the installation)
contain invalid boot code.

It could be argued that the installer should warn about the
issue but that's not really a ZFS-specific problem.

To get the attention from the people working on the installer
it might help to adjust the subject and to clarify the report.
Comment 2 Steven Hartland freebsd_committer 2016-07-10 15:51:35 UTC
If all of your disks arent accessible from your bios as bootable disks then when the loader comes to boot it will be missing disks hence in this situation it will to boot.