And yet I have this output from /proc/mdstat:
md1 : active raid1 sdb3[1] sda3[0]
288567164 blocks super 1.1 [2/2] [UU]
bitmap: 3/3 pages [12KB], 65536KB chunk
It is very strange. the responsiveness on small file i/o tends to
support the notion that this mirror really has a 64MB chunk size. This
is practically an order of magnitude larger than what is prudent. The
iowait on simple things like a sync or writing out small files seems
to support what mdstat is reporting. Of course, I'd like to change
this but how to do so without breaking the RAID or risking data is not
obvious.
--Jeff
On Wed, Mar 27, 2013 at 9:01 AM, Roy Sigurd Karlsbakk <roy@xxxxxxxxxxxxx> wrote:
> From the manual
>
> -c, --chunk=
> Specify chunk size of kibibytes. The default when creating an array is 512KB. To ensure compatibility with ear‐
> lier versions, the default when Building and array with no persistent metadata is 64KB. This is only meaningful
> for RAID0, RAID4, RAID5, RAID6, and RAID10.
>
> meaning - chunk size isn't relevant to a mirror
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