[DRBD-user] drbd and mkfs.gfs -j 3

Lars Ellenberg lars.ellenberg at linbit.com
Thu Aug 21 17:37:20 CEST 2008

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

On Thu, Aug 21, 2008 at 05:59:47PM +0300, Alex wrote:
> Hello drbd experts,
> I have drbd-8.2.6 working fine in dual-primary mode, mirroring 2 nodes.
> According to drbd howto 
> (http://www.drbd.org/users-guide-emb/s-gfs-create.html) i saw that since DRBD 
> does not support more than two nodes i can't format /dev/drbd0 using more 
> then 2 journals (2 nodes): mkfs -t gfs -p lock_dlm -j 2 /dev/drbd0 and MOUNT 
> IT on more then 2 nodes.
> Now, supposing that:
> - i have 4 machines grouped two by two in order to get two different drbd 
> devices /dev/drbd0 and /dev/drbd1
> - i am exporting /dev/drbd0 and /dev/drbd1 using iSCSI to the 5th macine
> - on the 5th machine, i am using lvm to join /dev/drbd{0,1} in one volume
> pvcreate /dev/drbd0 /dev/drbd1
> vgcreate myvg /dev/drbd0 /dev/drbd1
> lvcreate ... mylv myvg -> will result logical volume /dev/myvg/mylv
> Let say that /dev/myvg/mylv is exported now to another 3 nodes (again, via 
> iscsi for example).
> Question:
> Can i use now mkfs.gfs -p lock_dlm -j 3 /dev/myvg/mylv in order to have GFS on 
> top WITH 3 JOURNALS and of course to write on it from those 3 MACHINES AT THE 
> SAME TIME? If not, is any other way to achieve -j 3 ...?

keep it simple.  how about

 [as many iSCSI initiator clients as you want,          ]
 [ all accessing the same iSCSI target formatted as GFS ]
 |                                                      |
 |    iSCSI target cluster (SAN replacement)            | 
 |     in "simple" "standard" failover configuration    |
 | [drbd node a]-=-=-replication link-=-=-[drbd node b] |

: Lars Ellenberg                
: LINBIT HA-Solutions GmbH
: DRBD®/HA support and consulting    http://www.linbit.com

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