[DRBD-user] taking a drbd device back to md

Yan Seiner yan at seiner.com
Wed Feb 3 13:24:07 CET 2010

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

Mike Lovell wrote:
> Yan Seiner wrote:
>> I have a drbd device that I want to convert back to the underlying md 
>> device.  Is there some way to do that in place?  Or do I have to move 
>> all of the data off the device and reformat?
>> And how do I reformat the device to remove all of the drbd info?
> i don't think you have to do anything to be able to use the underlying 
> md device except stopping drbd and unloading the kernel modules. once 
> drbd is off, you should be able to mount and use any filesystems you 
> have on the md device without any changes.
> i wouldn't bother trying to remove the drbd metadata because it is 
> using a small portion of the disk. i haven't done it before and it 
> sounds kind of risky. iirc, it is only a couple megabytes of space for 
> hundreds of gigabytes of capacity. this is going to gain so little 
> space back i wouldn't risk it. i would just stop drbd, remove the 
> disks from drbd.conf, and use the device normally.

Exactly correct.  Being paranoid, I backed up the entire partition, then 
rebooted the machine making sure drbd would not start.  I could access 
the data with no problem.

This does beg a question, though.

I start drbd and then run fsck on the drbd device.  It would be faster 
to run fsck on the underlying file system, and then start drbd.  That 
would make life easier as one could do all the file operations before 
even starting the network at boot.

Is this advisable?



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