[DRBD-user] Resize with external meta data ?

Lars Ellenberg lars.ellenberg at linbit.com
Fri Jun 5 11:28:03 CEST 2009


On Fri, Jun 05, 2009 at 11:12:37AM +0200, Robert wrote:
> Hello,
> 
> while going through "Re: [DRBD-user] online shrinking errors / Centos5 
> drbd 8.3.1    from    Testing", I was asking myself:
> 
> How is meta data in general handled with resize ?
> 
> Lets assume device like shown in the graphics (where d1/2/3 are data 
> areas and m is the meta part).
> 
> 1) internal meta data
> 
> [ d1 | d2 | d3 | m ]
> 
> 1a) grow
> 
> Is the meta data moved to the end of the device ?
> [ d1 | d2 | d3 | d4 | m ]

yes.

> 1b) shrink
> 
> Is the meta data moved forward to device ?
> [ d1 | d2 | m ]

no.

> Or is meta data truncated ?  (this is the correct one, seems to be 
> answered by the e-Mail)
> [ d1 | d2 |    | m ]

yes.


> 2) external meta data
> (assuming the meta data device "just as large as it needs to be" 
> according to 
> http://www.drbd.org/users-guide/ch-internals.html#s-external-meta-data)
> 
> [ d1 | d2 | d3 ]  [ m ]
> 
> 2a) grow
> 
> Do I have to resize the meta device before resize of the device ?
> Is meta data automatically resized ?

if there is room enough in [m], you are fine.
if there is not enough room, drbd resize should only resize the
usable storage area to the maximum [m] can currently handle.

> 2b) shrink
> 
> Same questions as above

no further steps necessary.

> It would be great if this would be outlined in the admin guide.

-- 
: Lars Ellenberg
: LINBIT | Your Way to High Availability
: DRBD/HA support and consulting http://www.linbit.com

DRBD® and LINBIT® are registered trademarks of LINBIT, Austria.
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