On Fri, 23 Mar 2007, Peter Rabbitson wrote:

dean gaudet wrote:

quoted

On Thu, 22 Mar 2007, Peter Rabbitson wrote:

quoted

dean gaudet wrote:

quoted

On Thu, 22 Mar 2007, Peter Rabbitson wrote:

quoted

Hi,
How does one determine the XFS sunit and swidth sizes for a software
raid10
with 3 copies?

mkfs.xfs uses the GET_ARRAY_INFO ioctl to get the data it needs from
software raid and select an appropriate sunit/swidth...

although i'm not sure i agree entirely with its choice for raid10:

So do I, especially as it makes no checks for the amount of copies (3 in
my
case, not 2).

quoted

it probably doesn't matter.

This was essentially my question. For an array -pf3 -c1024 I get swidth =
4 *
sunit = 4MiB. Is it about right and does it matter at all?

how many drives?

Sorry. 4 drives, 3 far copies (so any 2 drives can fail), 1M chunk.

my mind continues to be blown by linux raid10.

so that's like raid1 on 4 disks except the copies are offset by 1/4th of 
the disk?

i think swidth = 4*sunit is the right config then -- 'cause a read of 4MiB 
will stride all 4 disks...

-dean