[DRBD-user] question regarding meta-data

Bernd Schubert bernd-schubert at web.de
Wed Oct 6 12:57:58 CEST 2004

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.


Hello,

> Could anyone tell me what the pros and cons of using 'internal'
> meta-data vs putting the meta-data on its own partition? I have read

I guess one of the reasons to have this option is for users upgrading from a 
previous drbd version (<0.7.0) to >= 0.7.0. 
E.g. people having a drbd-0.6 device will have a problem upgrading to 0.7.x 
since drbd now needs 128MB of metadata on the underlying device and so one 
would be forced to shrink the filesystem. As you might guess fs shrinking is 
always pretty dangerous. So setting up the meta data anywhere else might be 
the only solution in those cases.

> all the documentation (as far as I can see), but am not really sure
> which is more suitable. It mentions in the documentation that if you
> use meta-data internal, then you should 'shrink an existing filesystem
> first'. I'm not sure what this means. The main reason behind my question

see obove

> is whether one is easier to manage. For instance, if the primary crashes

Easier to manage are certainly internal metadata, except you are upgrading 
from a version <0.6.x

> and needs a rebuild, the documentation notes that you should 'remove any
> meta-data' before you attempt to sync it back from the acting primary.
> Is this option available with 'internal' meta-data?

Hmm, about some parts of documentation I sometimes don't care ;) The metadata 
make sure that only those parts are synchronized that differ, so I wouldn't 
delete it (with a very few exceptions where I don't trust the metadata 
anymore, e.g. when both nodes have been primary for some reasons).


Cheers,
	Bernd

-- 
Bernd Schubert
Physikalisch Chemisches Institut / Theoretische Chemie
Universität Heidelberg
INF 229
69120 Heidelberg
e-mail: bernd.schubert at pci.uni-heidelberg.de



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