----- Original Message -----
From: "Justin T. Gibbs"
...
> One issue I did spot in your patch is that you currently expose
> zfs_max_auto_ashift as a sysctl but don't clamp its value which would
> cause problems should a user configure values > 13.
I would expect the zio pipeline to simply insert an ashift aligned thunking
buffer for these operations, but I haven't tried going past an ashift of 13 in
my tests. If it is an issue, it seems the restriction should be based on
logical access size, not optimal access size.
Yes with your methodology you'll only see the issue if zfs_max_auto_ashift
and physical_ashift are both > 13, but this can be the case for example
on a RAID controller with large stripsize.
I'm not sure I follow. logical_ashift is available in our latest code, as is
the
physical_ashift. But even without the logical_ashift, why doesn't the zio
pipeline properly thunk zio_phys_read() access based on the configured ashift?
When I looked at it, which was a long time ago now so please excuse me if
I'm a little rusty on the details, zio_phys_read() was working more luck than
judgement as the offsets passed in where calculated from a valid start +
increment
based on the size of a structure within vdev_label_offset() with no ashift
logic applied that I cound find.
The result was pools created with large ashift's where unstable when I
tested.
Regards
Steve
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