[DRBD-user] ZFS backed resource running diskless

Martyn Spencer mdsreg_linbit at microdata.co.uk
Tue Oct 24 11:07:20 CEST 2017

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


I am running drbd 9 (drbdmanage 0.99.11, drbd-9.0.9) on CentOS7 and have 
set up a zfs backed drbd device. Having restarted the servers, on one 
node it is now operating as diskless and primary. I noted in the logs 
that for some reason the zfs device was seen as busy when drbdmanage 
attempted to create the resource.

I have a couple of questions. Firstly, is it possible to cause 
drbdmanage to wait until the device becomes available before attempting 
to create the resource? I imagine this could be something that I have to 
have systemd manage? I imagine that ZFS was importing the pool at the 
time the resource was created. Secondly, how do I cause drbdmanage to 
switch from diskless mode once the zfs pool and zvol become available?

Many thanks in advance.

An extract from the log is below:

Oct 24 09:11:55 san-2 drbdmanaged[7946]: ERROR drbdadm/stdout: drbdsetup 
new-resource vm-data-01 0
Oct 24 09:11:55 san-2 drbdmanaged[7946]: ERROR drbdadm/stdout: drbdsetup 
new-minor vm-data-01 101 0
Oct 24 09:11:55 san-2 drbdmanaged[7946]: ERROR drbdadm/stdout: drbdsetup 
new-peer vm-data-01 1 --_name=san-1 --cram-hmac-alg=sha1 
--shared-secret=XXXXXXXXXXXXXXXX --max-epoch-size=8192 
--max-buffers=20000 --rcvbuf-size=2097152 --sndbuf-size=2097152
Oct 24 09:11:55 san-2 drbdmanaged[7946]: ERROR drbdadm/stdout: drbdsetup 
new-path vm-data-01 1 ipv4:192.168.254.131:7001 ipv4:192.168.254.130:7001
Oct 24 09:11:55 san-2 drbdmanaged[7946]: ERROR drbdadm/stdout: drbdsetup 
peer-device-options vm-data-01 1 0 --set-defaults --c-plan-ahead=7 
--c-min-rate=4000 --c-max-rate=9000 --c-fill-target=1000
Oct 24 09:11:55 san-2 drbdmanaged[7946]: ERROR drbdadm/stdout: drbdmeta 
101 v09 /dev/zvol/zfs0/vm-data-01_00 internal apply-al
Oct 24 09:11:55 san-2 drbdmanaged[7946]: ERROR drbdadm/stdout: Operation 
canceled.
Oct 24 09:11:55 san-2 drbdmanaged[7946]: ERROR drbdadm/stderr: New 
resource vm-data-01
Oct 24 09:11:55 san-2 drbdmanaged[7946]: ERROR drbdadm/stderr: New minor 
101 (vol:0)
Oct 24 09:11:55 san-2 drbdmanaged[7946]: ERROR drbdadm/stderr: 
open(/dev/zvol/zfs0/vm-data-01_00) failed: Device or resource busy




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