[lustre-discuss] interrupted tar archive of an mdt ldiskfs

[John White]

Wow, I don’t see anything indicating that in the manual…  That’s quite worrying.  So in the end, a block level migration is likely safer here?

> On Jul 13, 2015, at 11:25 AM, Colin Faber <colin.faber at seagate.com> wrote:
> 
> On, 2.x systems an object index database is utilized to track inode <-> FID mapping. When you perform the traditional backup/restore this OI database becomes out of sync (because inodes numbers change).
> 
> You'll need to restore the OI after your backup, on early 2.x systems the only way this was possible was with the migrator tool from Xyratex. On later revisions this functionality was baked into the lfsck tool.
> 
> -cf
> 
> 
> On Mon, Jul 13, 2015 at 12:20 PM, John White <jwhite at lbl.gov> wrote:
> Yea, I’m benchmarking rsync right now, it doesn’t seem much faster than the initial tar was at all.
> 
> Can you elaborate on the risk on 2.x systems?..
> 
> > On Jul 13, 2015, at 11:17 AM, Colin Faber <colin.faber at seagate.com> wrote:
> >
> > modern rsync with ea support may work, but I'm not sure you're going to have much gains here as it's going to want to compare the inodes as well, so you're still stuck scanning all of them again.
> >
> > That said, it's worth a shot, and keep in mind this is risky on 2.x systems.
> >
> > -cf
> >
> >
> > On Mon, Jul 13, 2015 at 11:23 AM, John White <jwhite at lbl.gov> wrote:
> > So I was migrating an MDT from one array to another with a tar pipe using the flags recommended in the manual.  Got something like 92M out of 120M done when a coworker inadvertently rebooted the node that was doing the tar.  Is there any way to resume this action?  I know tar doesn’t have a resume function, but can a sufficiently modern rsync handle the EAs and such?  Luckily we still have the source in tact, but I’d *really* like to get this migration done during the downtime we have right now...
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