freebsd stable - Mar 2017 - moutnroot failing on zpools in Azure after upgrade from 10 to 11 due to lack of waiting for da0

> So, the kernel attempted to mount the root even before vmbus was attached
and,
> thus, before storvsc appeared and informed the kernel that it might be
holding
> the root.
> How ZFS was supposed to know that vmbus is ever going to appear?
> To me this sounds more like a problem with the Hyper-V drivers.
I am currently running with the patch which waits for a number fo 
seconds and retries the mount, and that appears t fix it. However I dont 
really like rnning a patched OS. How would I set about reporting this to 
Microsoft and getting it fixed, or getting the timeoutpatch commited ? 
Preferably both, as the timeout patch is generally a useful thing to 
have working for ZFS I think.

-pete.

On 16/03/2017 13:18, Pete French wrote:
> 
>> So, the kernel attempted to mount the root even before vmbus was
attached and,
>> thus, before storvsc appeared and informed the kernel that it might be
holding
>> the root.
>> How ZFS was supposed to know that vmbus is ever going to appear?
>> To me this sounds more like a problem with the Hyper-V drivers.
> 
> I am currently running with the patch which waits for a number fo seconds
and
> retries the mount, and that appears t fix it. However I dont really like
rnning
> a patched OS. How would I set about reporting this to Microsoft and getting
it
> fixed, or getting the timeoutpatch commited ? Preferably both, as the
timeout
> patch is generally a useful thing to have working for ZFS I think.
I don't like the delay and retry approach at all.
Imagine that you told the kernel that you want to mount your root from a ZFS
pool which is on a USB driver which you have already thrown out.  Should the
kernel just keep waiting for that pool to appear?

Microsoft provides support for FreeBSD Hyper-V drivers.
Please try to discuss this problem on virtualization@ or with sephe@ directly.


-- 
Andriy Gapon