[DRBD-user] failure on offline shrinking

Chad Phillips thehunmonkgroup at gmail.com
Tue May 19 15:42:31 CEST 2009

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

On May 18, 2009, at 12:01 PM, Stefan Seifert wrote:

> On Thursday 14 May 2009 18:37:47 Chad Phillips wrote:
>> running the latest CentOS release of drbd (8.2.6), and tried to  
>> shrink
>> a DRBD device backed by LVM.  here's an abbreviated running log of
>> what i did with the error at the end:
> Just a question: why didn't you shrink the drbd device online? From  
> the
> description in the drbd user's guide that would seem much easier and  
> thus
> safer.

from my searching, it didn't seem safe to shrink an ext3 filesystem  
online, only to grow it.

the alternate procedure i used looked like the only choice to me.

however, re-reading the doc, it now seems like it wouldn't be  
necessary to shrink the filesystem online in order to shrink the drbd  
device online.

would this procedure have worked instead?

1. leave drbd running in primary/secondary
2. umount the filesystem
3. resize the filesystem offline
4. drbdadm -- --size=new-size resize resource
5. lvreduce the partition
6. remount the filesystem

if the above procedure would work, then i think the documentation in  
the 'Shrinking on-line' section should be reworded, as it's currently  
easy to misinterpret it to mean that the filesystem must also be  
shrunk online in order for drbd to be shrunk online.

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