Re: I/O topology fixes for big physical block size

Eric Sandeen
2010-09-30T17:07:09Z

On 09/30/2010 11:30 AM, Ted Ts'o wrote:
> On Tue, Sep 28, 2010 at 04:36:42PM -0500, Eric Sandeen wrote:
>> Ok, then it sounds like mkfs.ext4's refusal to make fs blocksize less
>> than device physical sectorsize without -F is broken, and that should
>> be removed. I'd say issue a warning in the case but if there's a 16k
>> physical device maybe there's no point in warning either?
>
> If the device physical sectorsize is that big, should we perhaps use
> that as a hint to align writes to that blocks aligned with that
> physical sectorsize? Right now we use the optimal I/O size, but if
> the optimal I/O size is not specified and the physical sectorsize is,

I can't keep track of all the parameters, is it ever true that optimal
I/O size isn't specified?

> say, 16k or 32k, maybe we should use to calculate for
> s_raid_stripe_width?

Perhaps, though really ext4 still doesn't do -that- much with the value,
anyway...

-Eric