[DRBD-user] Is it a Split Brain situation or something else?

Paul O'Rorke paul at tracker-software.com
Tue Apr 10 22:16:56 CEST 2018


Hi list,

I have a number of stacked resources replicating from 2 hosts to a 
common third host.  There are three resources 'stuck' waiting for a 
connection with a state "Inconsistent".  I have tried discarding the 
data on this third node and reconnecting with *drbdadm connect 
--discard-my-data* but I'm not having any luck.

I even (lv)removed the backing device, (lv)created a new volume, said 
yes to remove the existing drbd meta-data:

root at trk-kvm-03:/etc/drbd.d# lvcreate -L 300G -n winserv-data trk-kvm-03-vg
WARNING: drbd signature detected on /dev/trk-kvm-03-vg/winserv-data at 
offset 322122543164. Wipe it? [y/n]: yes
   Wiping drbd signature on /dev/trk-kvm-03-vg/winserv-data.
   Logical volume "winserv-data" created.

and ran drbdadm create-md to create new meta-data.

root at trk-kvm-03:/etc/drbd.d# drbdadm create-md fileserver-data-U
md_offset 322122543104
al_offset 322122510336
bm_offset 322112679936

Found some data

  ==> This might destroy existing data! <==

Do you want to proceed?
[need to type 'yes' to confirm] yes

initializing activity log
NOT initializing bitmap
Writing meta data...
New drbd meta data block successfully created.
success

I have 12 resources being replicated to this host and I am seeing this 
on three of them.

root at trk-kvm-03:~# drbdadm connect --discard-my-data fileserver-data-U

root at trk-kvm-03:/etc/drbd.d# drbd-overview
  20:fileserver-data-U/0    WFConnection Secondary/Unknown 
Inconsistent/DUnknown
  30:svn-U/0                Connected    Secondary/Primary 
UpToDate/UpToDate
  40:MySQL-Slave-R-U/0      Connected    Secondary/Primary 
UpToDate/UpToDate
  60:rt44-U/0               Connected    Secondary/Primary 
UpToDate/UpToDate
  70:sharepoint_server-U/0  Connected    Secondary/Primary 
UpToDate/UpToDate
  80:techwiki-U/0           Connected    Secondary/Primary 
UpToDate/UpToDate
  90:sdkHelp-U/0            WFConnection Secondary/Unknown 
UpToDate/DUnknown
100:sql-srv-2014-U/0       Connected    Secondary/Primary UpToDate/UpToDate
101:fileserver-U/0         Connected    Secondary/Primary UpToDate/UpToDate
110:informer-U/0           Connected    Secondary/Primary UpToDate/UpToDate
120:convirt-U/0            Connected    Secondary/Primary UpToDate/UpToDate
130:user_uploads-U/0       WFConnection Secondary/Unknown UpToDate/DUnknown

This third node, connected using protocol A, is intended for disaster 
recovery only so none of these resources should ever have been the 
primary so I am leaning away from a split-brain however the symptoms 
appear to me to be like a split brain.  I'm not seeing anything related 
to split-brain in the logs.

The resources are UpToDate on the primaries:

root at trk-kvm-01:/etc/drbd.d# drbd-overview
   1:fileserver/0               Connected Primary/Secondary 
UpToDate/UpToDate *fileserver        vda virtio
   2:fileserver-data/0          Connected Primary/Secondary 
UpToDate/UpToDate *fileserver        vdb virtio
   3:svn/0                      Connected Secondary/Primary 
UpToDate/UpToDate _svn               vda virtio
   4:MySQL-Slave-R/0            Connected Secondary/Primary 
UpToDate/UpToDate _MySQL-Slave-R     vda virtio
   5:prtg-srv/0                 Connected Secondary/Primary 
UpToDate/UpToDate _prtg-srv          vdb virtio
   6:rt44/0                     Connected Primary/Secondary 
UpToDate/UpToDate *RT44              vda virtio
   7:sharepoint_server/0        Connected Primary/Secondary 
UpToDate/UpToDate *sharepoint_server hda ide
   8:techwiki/0                 Connected Secondary/Primary 
UpToDate/UpToDate _techwiki          vda virtio
   9:sdkHelp/0                  Connected Secondary/Primary 
UpToDate/UpToDate _sdkHelp           vda virtio
  10:sql-srv-2014/0             Connected Primary/Secondary 
UpToDate/UpToDate *sql-srv-2014      vda virtio
  11:informer/0                 Connected Secondary/Primary 
UpToDate/UpToDate _informer          vda virtio
  12:convirt/0                  Connected Primary/Secondary 
UpToDate/UpToDate _convirt           vda virtio
  13:user_uploads/0             Connected Secondary/Primary 
UpToDate/UpToDate _user_uploads      vda virtio
  20:fileserver-data-U/0   ^^2  WFConnection Primary/Unknown   
UpToDate/DUnknown
  60:rt44-U/0              ^^6  Connected Primary/Secondary 
UpToDate/UpToDate
  70:sharepoint_server-U/0 ^^7  Connected Primary/Secondary 
UpToDate/UpToDate
100:sql-srv-2014-U/0      ^^10 Connected Primary/Secondary 
UpToDate/UpToDate
101:fileserver-U/0        ^^1  Connected Primary/Secondary 
UpToDate/UpToDate
120:convirt-U/0           ^^12 Connected Primary/Secondary 
UpToDate/UpToDate

root at trk-kvm-02:~/qemu# drbd-overview
   1:fileserver/0             Connected    Secondary/Primary 
UpToDate/UpToDate _fileserver        vda virtio
   2:fileserver-data/0        Connected    Secondary/Primary 
UpToDate/UpToDate _fileserver        vdb virtio
   3:svn/0                    Connected    Primary/Secondary 
UpToDate/UpToDate *svn               vda virtio
   4:MySQL-Slave-R/0          Connected    Primary/Secondary 
UpToDate/UpToDate *MySQL-Slave-R     vda virtio
   5:prtg-srv/0               Connected    Primary/Secondary 
UpToDate/UpToDate
   6:rt44/0                   Connected    Secondary/Primary 
UpToDate/UpToDate _RT44              vda virtio
   7:sharepoint_server/0      Connected    Secondary/Primary 
UpToDate/UpToDate _sharepoint_server hda ide
   8:techwiki/0               Connected    Primary/Secondary 
UpToDate/UpToDate *techwiki          vda virtio
   9:sdkHelp/0                Connected    Primary/Secondary 
UpToDate/UpToDate *sdkHelp           vda virtio
  10:sql-srv-2014/0           Connected    Secondary/Primary 
UpToDate/UpToDate _sql-srv-2014      vda virtio
  11:informer/0               Connected    Primary/Secondary 
UpToDate/UpToDate *informer          vda virtio
  12:convirt/0                Connected    Secondary/Primary 
UpToDate/UpToDate _convirt           vda virtio
  13:user_uploads/0           Connected    Primary/Secondary 
UpToDate/UpToDate *user_uploads      vda virtio
  30:svn-U/0             ^^3  Connected    Primary/Secondary 
UpToDate/UpToDate
  40:MySQL-Slave-R-U/0   ^^4  Connected    Primary/Secondary 
UpToDate/UpToDate
  80:techwiki-U/0        ^^8  Connected    Primary/Secondary 
UpToDate/UpToDate
  90:sdkHelp-U/0         ^^9  WFConnection Primary/Unknown 
UpToDate/DUnknown
110:informer-U/0        ^^11 Connected    Primary/Secondary 
UpToDate/UpToDate
130:user_uploads-U/0    ^^13 WFConnection Primary/Unknown UpToDate/DUnknown

I  am keen to get these three resources replicating.  Any suggestions 
what I'm missing?

regards
-- 

*Paul O'Rorke*
*Tracker Software Products (Canada) Limited *
www.tracker-software.com <http://www.tracker-software.com/>
Tel: +1 (250) 324 1621
Fax: +1 (250) 324 1623

<http://www.tracker-software.com/>

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