upgrade_0.6.x_to_0.7.0.txt

DRBD upgrade instructions from 0.6.x to 0.7.0

* Since drbd-0.7.x is protocol incompatible to drbd-0.6.x you need
  to do an offline upgrade. I.e. no "rolling" upgrade possible.

  Make sure that the devices are in sync, make both sides secondary
  first and then stop DRBD on both nodes.

* In drbd-0.7.0 each DRBD resource needs 128MB of storage on
  some block device for its meta data. (With this /var/lib/drbd
  disappeared.)

  In order to do this upgrade you either need to

   A) shrink your filesystems on the DRBD devices by at least 128MB, or
   B) grow the backing_storage of the DRBD devices by at least 128MB, or
   C) have one separate block_device for all meta data

  A)
  ext2/ext3   resize2fs
  reiserfs    resize_reiserfs     
  xfs         xfsdump, xfsrestore ; xfs can only grow

  B)
  lvresize    in case you run DRBD on LVM
  (fdisk)     (Only do this if you know what you are doing.)

  C)
  The size of the meta-data device needs to be at least n*128MB,
  where n is the number of DRBD resources you want to use.

* Update your drbd.conf file:
  - Change it to the new syntax.
  - Remove the disk-size parameter from your drbd.conf
  - Add the meta-disk settings
  - Remove tl-size
  - Change sync-min & sync-max to sync { rate }
  - Add the al-extents setting

* Start DRBD on both nodes

* Tune the al-extents setting to balance the number of updates
  to the metadata per minute (see cat /proc/drbd number "al:") vs
  the expected resync time. 

* In case you are using heartbeat:
  - change datadisk to drbddisk in your haresources file
  - Add a Filesystem resource just after the drbddisk resorce
    E.g. Filesystem::/dev/nb0::/mnt/ha0::ext3
  - Remove the lines form /etc/fstab containing /dev/nbX