[DRBD-user] Resizing without active peer

Lars Ellenberg lars.ellenberg at linbit.com
Wed Sep 10 18:47:40 CEST 2008

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

On Tue, Sep 09, 2008 at 11:51:24AM +0200, Michael Rhyner wrote:
> Hello drbd users
> I use DRBD, but have one storage system at the moment, it's planned to  
> add the peer later, so we set up our logical volumes alrady on top of  
> DRBD. We use a stacked setup, means underlying EVMS - DRBD - EVMS.
> Now we would like to enlarge the DRBD space of resource "r2" by  
> enlarging the underlaying EVMS volume.
> cat /proc/drbd shows this:
>  2: cs:WFConnection st:Primary/Unknown ds:UpToDate/DUnknown C r---
>     ns:0 nr:0 dw:40807895 dr:12598 al:10086 bm:6253 lo:0 pe:0 ua:0 ap:0
> 	resync: used:0/61 hits:0 misses:0 starving:0 dirty:0 changed:0
> 	act_log: used:0/3833 hits:40796120 misses:10124 starving:0 dirty:38  
> changed:10086
> So we resize the underyling EVMS volume from 100 GB to 150 GB, then  
> execute this command: drbdadm resize r2
> As assumed, the drbd disk device shows still only 100 GB within EVMS.
> I know that connection state should be "Connected", but is there a  
> possibility to circumvent this situation and nevertheless enlarge the  
> volume on-line, because I don't have a peer yet, and therefore I  
> wouldn't risk to render something inconsistent.

should work if you first "disconnect".
I expect a "drbdadm resize" to pickup the new device size
on a "StandAlone" node as well.

as long as it has never seen the peer so far,
it should even propagate the new size to upper layers,
so the stacked EVMS should notice.

if drbd has ever seen its peer, it has stored the peers lower level
device size, so it will refuse to grow larger than that for obvious
reasons, unless you connect it to the peer, and the peer confirms
that it could handle a larger device size now.

: Lars Ellenberg                
: LINBIT HA-Solutions GmbH
: DRBD®/HA support and consulting    http://www.linbit.com

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