[DRBD-user] DRBD over an existing filesystem

Lars Ellenberg Lars.Ellenberg at linbit.com
Fri Mar 26 15:56:39 CET 2004

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


/ 2004-03-26 15:23:14 +0100
\ Philipp Reisner:
> Maybe there is something wrong with -pre5's read_gc.pl, or 
> the metadata handling in -pre5. I will release -pre6 over
> the weekend.

Ok.
With CVS at least, read_gc.pl is just fine,
and the suggested approach WorksForMe ...

 From looking at the code in drbd_fs.c,
It still is impossible to *grow* the size if I have a la_size,
and I am not connected. This is ok, since it prevents the unwary from
shooting themselves.
BUT, this is at least a usability bug, if one cannot override ...

And, please initialize to default values uppon "drbdsetup down" !

Why?

 # wipeout metadata
 # read_gc.pl
 > state file corrupt at ./read_gc.pl line 39.
 # load drbd module
 # read_gc.pl
 > state file corrupt at ./read_gc.pl line 39.
 # drbdadm attach all
 # read_gc.pl
 >      r0 | 1/c |   1 |   1 |   1 |   1 | 0/s | 0/n |      0 KB
 # drbdsetup /dev/nb0 resize -d $[512-128]M
 # read_gc.pl
 >      r0 | 1/c |   1 |   1 |   1 |   1 | 0/s | 0/n | 393216 KB
 # drbdsetup /dev/nb0 resize -d 1
 # read_gc.pl
 >      r0 | 1/c |   1 |   1 |   1 |   1 | 0/s | 0/n |      1 KB
 # drbdsetup /dev/nb0 resize -d 370M
 # read_gc.pl
 >      r0 | 1/c |   1 |   1 |   1 |   1 | 0/s | 0/n |      1 KB
 # drbdadm down all
 # wipeout metadata
 # read_gc.pl
 > state file corrupt at ./read_gc.pl line 39.
 # drbdadm attach all
 # read_gc.pl
 >      r0 | 1/c |   1 |   1 |   1 |   1 | 0/s | 0/n |      1 KB

 doh!
 so the -> la_size member survived the down, and now pollutes metadata
 of a completely unrelated device!

 # drbdadm down all
 # wipeout metadata
 # unload module
 # reload module
 # drbdadm attach all
 # read_gc.pl
 >      r0 | 1/c |   1 |   1 |   1 |   1 | 0/s | 0/n |      0 KB




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