Hi Shailendra and Steve,
Shailendra Tripathi wrote:
Your guess appears to be correct. md_ioctl returns nr which
is total number of disk in the array including the spare disks. However,
XFS function md_get_vol_stripe does not take spare disk into account. It
needs to subtract spare_disks as well.
However, md.spare_disks returned by the call returns spare + parity
(both). So, one way could be substract spare_disks directly. Otherwise,
the xfs should rely on md.raid_disks. This does not include spare_disks
and nr.disks should be changed for that.
When I run my program md_info on raid5 array with 5 devices and 2
spares, I get
[root@ga09 root]# ./a.out /dev/md11
Level 5, disks=7 spare_disks=3 raid_disks=5
Steve can you please compile the pasted program and run on your system
with md prepared. It takes /dev/md<no> as input.
In your case, you should get above line as:
Level 6, disks=11 spare disks=3 raid_disks=10
info.level = mddev->level;
info.size = mddev->size;
info.nr_disks = nr;
info.active_disks = active;
info.working_disks = working;
info.failed_disks = failed;
info.spare_disks = spare;
I'm not that au fait with RAID and md, but looking at what you wrote,
Shailendra, and the md code, instead of your suggestions
(what I think are your suggestions:) of:
(1) subtracting parity from md.raid_disk (instead of md.nr_disks)
where we work out parity by switching on md.level
(2) using directly: (md.nr_disks - md.spares);
that instead we could use:
(3) using directly: md.active_disks
*swidth = *sunit * md.active_disks;
I presume that active is the working non spares and non-parity.
Does that make sense?