Re: ceph and rsync

[Alessandro Brega <alessandro.brega1@xxxxxxxxx>]

2016-12-16 10:19 GMT+01:00 Wido den Hollander <wido@xxxxxxxx>:

> Op 16 december 2016 om 9:49 schreef Alessandro Brega <alessandro.brega1@xxxxxxxxx>:
>
>
> 2016-12-16 9:33 GMT+01:00 Wido den Hollander <wido@xxxxxxxx>:
>
> >

> > > Op 16 december 2016 om 9:26 schreef Alessandro Brega <
> > alessandro.brega1@xxxxxxxxx>:
> > >
> > >
> > > Hi guys,
> > >
> > > I'm running a ceph cluster using 0.94.9-1trusty release on XFS for RBD
> > > only. I'd like to replace some SSDs because they are close to their TBW.
> > >
> > > I know I can simply shutdown the OSD, replace the SSD, restart the OSD
> > and
> > > ceph will take care of the rest. However I don't want to do it this way,
> > > because it leaves my cluster for the time of the rebalance/ backfilling
> > in
> > > a degraded state.
> > >
> > > I'm thinking about this process:
> > > 1. keep old OSD running
> > > 2. copy all data from current OSD folder to new OSD folder (using rsync)
> > > 3. shutdown old OSD
> > > 4. redo step 3 to update to the latest changes
> > > 5. restart OSD with new folder
> > >
> > > Are there any issues with this approach? Do I need any special rsync
> > flags
> > > (rsync -avPHAX --delete-during)?
> > >
> >
> > Indeed X for transferring xattrs, but also make sure that the partitions
> > are GPT with the proper GUIDs.
> >
> > I would never go for this approach in a running setup. Since it's a SSD
> > cluster I wouldn't worry about the rebalance and just have Ceph do the work
> > for you.
> >
> >

> Why not - if it's completely safe. It's much faster (local copy), doesn't
> put load on the network (local copy), much safer (2-3 minutes instead of
> 1-2 hours degraded time (2TB SSD)), and it's really simple (2 rsync
> commands). Thank you.
>

I wouldn't say it is completely safe, hence my remark. If you copy, indeed make sure you copy all the xattrs, but also make sure the partitions tables match.

That way it should work, but it's not a 100% guarantee.

Ok, thanks!  Can a ceph dev confirm? I do not want to loose any data ;)

Alessandro

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