Re: IO failures with SMR drives at latest kernel versions

[Hannes Reinecke <hare@suse.de>]

On 08/22/2015 07:23 PM, Anatol Pomozov wrote:
> Hi
> 
> On Fri, Aug 21, 2015 at 10:37 PM, Anatol Pomozov
> <anatol.pomozov@gmail.com> wrote:
>> Discs are from different batches and I was a bit surprised to see
>> identical failures at the same time. I was ready send the drives to
>> RMA but then I discovered this thread
>> https://bbs.archlinux.org/viewtopic.php?id=199351 A lot of people
>> report the same problem as mine. It was found that the problem appears
>> only starting from 3.19, with kernel 3.18 or Windows these drives work
>> fine. It is recommended to revert this change
>> 9162c6579bf90b3f5ddb7e3a6c6fa946c1b4cbeb "libata: Implement
>> ATA_DEV_ZAC" that seems fixes the issue.
> 
> I looked at this commit and it actually adds SMR support to SCSI
> layer. Reverting ATA_DEV_ZAC means going back to zones-unaware
> algorithms. It is suboptimal but still much better than IO failures
> and "BTRFS: lost page write due to I/O error on /dev/sdc" errors I see
> at my computer.
> 
> If this SMR support is considered as non-stable, can we at least get a
> kernel boot (or config) option that disables ZAC?
> 
Again: Has anybody actually _tested_ that reverting this patch fixes
this issue?
Or even a proper bisect?

Needless to say, my drives work without issues, so I can't really
reproduce this issue.

Which disks are these?

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		               zSeries & Storage
hare@suse.de			               +49 911 74053 688
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
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