[Lustre-discuss] clean unmounting of OST with external journal

[Samuel Aparicio]

i just confirmed this is what is happening: the minor number changes after a network/driver reload. I will have to look into the mechanics to see if this can be made fixed.

... don't see a journal_dev option in mount.lustre although the path to the device is hardcoded at mkfs time ...
is the hardcoded path made use of .. it looks as if it's the superblock hint.

Professor Samuel Aparicio BM BCh PhD FRCPath
Nan and Lorraine Robertson Chair UBC/BC Cancer Agency


On Mar 6, 2011, at 6:44 PM, Oleg Drokin wrote:

> Hello!
> 
> On Mar 6, 2011, at 8:43 PM, Samuel Aparicio wrote:
>> now an attempt to re-mount the OST fails with 
>> LDISKFS-fs (md14): failed to open journal device unknown-block(152,225): -6
>> 
>> an e2fsck fixes this external superblock 
>> 
>> [root at OST2 ~]# e2fsck -j /dev/etherd/e9.24p1 /dev/md14
>> e2fsck 1.41.10.sun2 (24-Feb-2010)
>> Superblock hint for external superblock should be 0x409802.  Fix<y>? yes
> 
> Hm, to me it sounds like after you restarted the network and reimport AoE,
> then it created the device with different minor/major.
> I believe that the path to the journal is stored in superblock or some such, not just the "hint" on how to find the journal.
> (hint is just major:minor).
> (-6 is "No such device or address", I wonder where does that come from inside of the kernel)
> 
>> 
>> the subsequent OST is marked clean and can be re-mounted.
>> 
>> I am not sure why this is happening. The external raid partitions of relevance are all presented under the same /dev/ device when they are stopped/re-started.
>> any ideas?
> 
> Did you check that device major,minor pair is the same every time?
> 
> I guess you can use journal_dev mount option to point ldiskfs at the proper journal device.
> 
> Bye,
>    Oleg