[Lustre-discuss] Force read-only ost mount

[Zachary Beebleson]

Is there a way to manually mount an ost read-only? I tried 'mount -t 
lustre -o ro ost_device mountpoint', but got a

mount.lustre: mount /dev/data1recov/ost1 at /mnt/os1brecov failed: 
Transport endpoint is not connected

I know if lustre detects a serious enough problem, ldiskfs error say, it 
will remount the ost read-only, but I would like to manually force this.

A raid logical volume on an oss has some problems and I'm trying to 
transfer one of two osts to another oss (I believe this is possible by 
umounting lustre from all servers/clients, executing a 'tunefs.lustre 
--writeconf' on all lustre servers and the related devices, and 
remounting --- with the copied ost replacing the problematic one). In 
order to minimize downtime, I would like to work with a static ost image 
-- so I can transfer a faithful copy back, after I repair the raid 
problem. I did deactivate the ost device on the mds, but I'm worried about 
changes to files that live on the ost (I wasn't planning on creating 
another image).

Thanks,
Zach