On 11/15/18 5:40 AM, Niklas Hambüchen wrote:
On 2018-09-03 08:48, Guoqing Jiang wrote:
On 08/31/2018 05:18 PM, Guoqing Jiang wrote:
On 08/30/2018 10:32 AM, Niklas Hambüchen wrote:
Is it expected that raid1 turns into raid0 in this way when during a reboot an expected device is not present (e.g. because it is unplugged or was replaced)?
If yes, what is the idea behind that, and why doesn't it go into the normal degraded mode instead?
Is it possible to achieve that? I had hoped that I would be able to continue booting into a degraded system if a disk fails during a reboot (and then be notified of the degradation by mdadm as usual), but this isn't the case if an array comes back as raid0 and inactive after reboot.
Finally, if these topics are already explained somewhere, where can I read more about it?
Maybe we need to call do_md_run when assembling an array, need to investigate it.
It doesn't work, actually the array can be activated by "echo active > /sys/block/md0/md/array_state".
Thank you, this echo worked!
I just confirmed it on another machine.
It immediately brings the array back from the wrong "Raid Level : raid0" into the correct "raid1".
I also noticed that `mdadm --run /dev/md0` has the same effect.
But `mdadm --run --readonly /dev/md0` didn't, it says "/dev/md0 does not appear to be active".)
So remaining question is:
Why does the device appear as raid0 at all?
I would expect it to come back from reboot as a degraded raid1, because that's what it is (and mdadm seems to think so too as soon as you activate it).
Pls re-compile mdadm with this, and see if it works.
diff --git a/util.c b/util.c
index c26cf5f3f78b..bd00ebde06a9 100644
--- a/util.c
+++ b/util.c
@@ -1919,6 +1919,7 @@ int set_array_info(int mdfd, struct supertype *st,
struct mdinfo *info)
* and older kernels
*/
mdu_array_info_t inf;
+ struct mdinfo info1;
int rv;
if (st->ss->external)
@@ -1927,6 +1928,11 @@ int set_array_info(int mdfd, struct supertype
*st, struct mdinfo *info)
memset(&inf, 0, sizeof(inf));
inf.major_version = info->array.major_version;
inf.minor_version = info->array.minor_version;
+
+ /* set the correct level based on sb */
+ st->ss->getinfo_super(st, &info1, NULL);
+ inf.level = info1.array.level;
+
rv = md_set_array_info(mdfd, &inf);
return rv;
Thanks,
Guoqing
