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

[Samuel Aparicio]

I notice the following behaviour on a test system while setting up init.d scripts to allow clean shutdown and re-start of an OSS (lustre 1.8.4)

format an OST with an external journal. The external journal is located on a raid10 array connected to one of the network interfaces (aoe).

the OST was tested in a filesystem and appears to operate normally.
I can cleanly mount and unmount the OST with mount / umount

however the following sequence leads to an unmountable filesystem on startup

sync
umount  the OST
sync (again for certainty)
stop the internal and external raid arrays
stop network interface

restart network interface
bring up the internal and external raid arrays

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

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?

the workaround is maybe to put an e2fsck into the startup scripts (maybe not a bad idea?) but seems like a kludge.



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