[OmniOS-discuss] panic: bd_strategy after new loader installed

[Paul B. Henson]

On Sun, Jun 04, 2017 at 05:15:58PM +0200, Andries Annema wrote:

> Can someone please clarify this matter? Does this boot problem apply 
> only to Advanced Format SAS drives or also to their SATA counterparts? 

I'm guessing here, so take it for what it's not worth ;). But I'm pretty
sure it would apply to disks in general.

> And what does the "native" mean: is that "4kB physical AND 4kB logical 
> block size" as opposed to "4kB physical with 512B logical block size"?

At this point I'm thinking the loader is only broken for disks that have
a *logical* sector size of 4k, as opposed to those that have a physical
sector size of 4k but still maintain a logical sector size of 512b.

> It looks to me that the T10-thingy (as can only be used on SAS-drives, 
> right?) changes the block size to something other than 512/4096 bytes 
> which, in turn, is not recognized by the new loader.

I'm not sure if that's because it's an oddball size or just because it's
not 512 bytes. Those might still be broken even once they fix it for 4k
sectors.

> More specific to my use case, if I may: I am running WD Red SATA drives 
> (4TB and 6TB, WDxxEFRX) which report "512 byte logical / 4096 physical" 
> block size. Would it be a death sentence when I upgrade my r151014's to 
> 022 before this loader bug has been resolved?

Dan said he upgraded his system with WD red drives with no issues, we're
still waiting to hear back from him to confirm that. I was initially
surprised that nobody would have caught a loader issue with 4k drives,
as they're been around forever in technology terms, my system with WD
reds was build almost 9 years ago.

On the other hand, drives that both have physical 4k sectors *and*
report logical 4k sectors are much less common AFAIK. I'm betting
*those* are the ones that the loader doesn't support. Which makes sense,
as the bug report indicates that the loader assumes sectors are 512b,
and 4k physical/512b logical drives can still be read by the bios in
512b chunks. As opposed to 4k logical sector drives, which can't be.
 
> With such a seemingly high risk of a non-booting system after upgrade, 
> one cannot get too much clarification beforehand, I'd say. Any help is 
> much appreciated.

You don't *have* to switch to loader as part of the upgrade. You can
stick with trusty old grub for now and then migrate to loader later once
this is all sorted out. That's probably what I'm going to do for now.

The warning I added to the wiki should probably be narrowed to warn just
people with 4k physical sector drives, but it doesn't hurt anything to
wait to migrate to loader (unless you're a BE maniac) so pending news
from a more authoritive source I think I'll let it be better safe than
sorry for now.