DRBD

From DWIKI

Distributed Replicated Block Device


Links

See also: http://www.gluster.org/ and http://ceph.com/

Stacked resources

Support

Tools

drbdadm

drbd-overview

drbdsetup

Docs

Recovery

GFS on DRBD


Cheatsheet

Make device primary

drbdadm primary yourdeviceID

or

drbdsetup /dev/drbdX primary -o


Grow resource

On both nodes:

lvextend -L+10G /dev/DRBD/myresource

On one node:

drbdadm resize myresource


Check resource file

Editing files in /etc/drbd.d/ is a bad plan, to check syntax first:

drbdadm dump -c /tmp/test.res

FAQ

1: State change failed: (-2) Need access to UpToDate data

when you get that tryinng to make a node/resource primary, try

drbdadm primary drbdX --force

calculate metadata size

https://serverfault.com/questions/433999/calculating-drbd-meta-size


Cs=`blockdev --getsz /dev/foo`
Bs=`blockdev --getpbsz /dev/foo`

TODO finish this

'mydrbd' not defined in your config (for this host).

If drbdadm create-md throws this, 'this host' is the clue: it must match `hostname`


https://newbiedba.wordpress.com/2015/09/21/drbd-not-defined-in-your-config-for-this-host/

show resource sizes

lsblk

commands to show info

drbdmon
drbdtop


resolving split brain issues

diskless

You might try

drbdadm attach drbd0


sync is slow


On secondary:

drbdadm disk-options --c-plan-ahead=0 --resync-rate=50M drbd0and 

and to reset after sync:

drbdadm adjust drbd0

show configuration

drbdsetup show


show more info

drbdsetup show-gi <minor-number>

update network settings

drbdsetup net-options 10.0.0.1 10.0.0.2  --sndbuf-size=2M


mount: unknown filesystem type 'drbd'

Usually means your node is not primary. If you're sure you know what you're doing you can use

mount -t ext4 /dev/drbd1 /drbdmount

reload configuration

drbdadm adjust all


show configuration of resource

drbdsetup /dev/drbd0 show


resource unknown

First try

drbdadm up resourcename

Command 'drbdmeta 1 v08 /dev/drbd0 internal apply-al' terminated with exit code 20

Most likely split brain issue, check dmesg etc

wfconnection

Could be split brain situation

drbdadm -- --discard-my-data connect resource

Split brain issue

To force updating resource

drbdadm invalidate resource

cs:WFReportParams ro:Secondary/Unknown ds:UpToDate/DUnknown

connection is made, waiting for more