drbd diskless mode

I am still scratching my head over this one--that it is actually possible.  Sure I ran diskless stuff like iSCSI with special hardware cards before, but drbd?

I detached the disk and then turned the resource into active.  So basically the node, without a disk, is talking to a node, with a disk, and pretending that the disk is local:

[root@drb6 tmp]# drbdadm status
r0 role:Primary
  disk:Diskless
  drb5 role:Secondary
    peer-disk:UpToDate

[root@drb6 tmp]# df
Filesystem          1K-blocks    Used Available Use% Mounted on
/dev/drbd0            1014612   33860    964368   4% /mnt/tmp


On this node, /dev/drbd0 has no disk backing store for drbd0.  drbd0 is for all practical purposes a normal block device.

That is amazing...


jondz