[DRBD-user] drbd and lvm

Lars Ellenberg Lars.Ellenberg at linbit.com
Sat Mar 20 00:42:43 CET 2004


/ 2004-03-19 17:04:33 -0500
\ Todd Denniston:
> Lars Ellenberg wrote:
> > 0.7 needs 128MB stable storage for persistant bitmap and metadata
> > per device, either at the end of the lower level device, or within
> > some other dedicated block device.
> > 
> > You can have all your DRBDs share one dedicated partition for the
> > metadata, provided it is large enough.
> Question: does it need to be a raw partition or can it just be space inside
> one of the file systems on a DRBD device?

As I said, you can have it at the end of the lower level device.
Not "within the filesystem", but on the same "lower level device"
as the file system.
We plan to have the option to store meta data within some file
later somewhen... but for now it is directly on the device.

> on my system I have one partition that is used for the /var/lib/nfs stuff and
> perhaps in the future some NIS files but on the whole I am realizing I made it
> way bigger than needed for just nfs.
> /dev/nb0              3.7G   33M  3.5G   1% /nfsstate
> lets see 7 DRBD devices * 128MB =~896MB... yep enough space but is it the
> right type?

You can resize the file system on each drbd: shrink by 128MB+ ... 
then at the very end of the device you have unused (by the
filesystem) space, where drbd 0.7 can save its bitmap and stuff.

> Also, after changing to 0.7.? on both nodes will we need to restore from a
> backup or, will the physical partition content layout be the same?

No, you won't need a full restore cycle.
The first part of the device (or the whole device, if you choose
to save the meta data somewhere else) will remain transparent.

	Lars Ellenberg



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