On 01/07/2013 04:33 PM, Bradley C. Kuszmaul wrote:
What is the largest data block size that I'm likely to run into with xfs?
I ask, since I'm doing hole punching, and I don't want to incur the I/O
required to zero unaligned boundaries. So I want to keep the holes I punch
sufficiently well aligned.
I think that you really need to worry about the block sizes below XFS - the
storage block size specifically. Upstream (and modern distros like
RHEL/SLES/etc) do work to export out alignment requirements and optimal IO sizes.
You can find them in /sys/block/sda/. Martin Peterson wrote up a good overview
of what we have in there: