[DRBD-user] DRBD Primary/Primary and iscsi multipathing

Jakov Sosic jakov.sosic at srce.hr
Thu Aug 13 15:40:03 CEST 2009

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


I've googled around, and I just can't find many information about
Primary/Primary setup and iscsi export of drbd device. I found some
information about possible corruption, but still nothing with hard

Problem in my case with Primary/Slave and HeartBeat is that after
failover, all iscsi sessions are lost, and that results in failed
mounts on client side. Also, on some of the volumes there are XEN
machines which makes it even more problematic. With Primary/Primary,
failover works on the client side via multipathing and clients just
don't notice the fail of one of the DRBD nodes (except the multipathing
layer, offcourse). Multipathd tries to connect to iscsi target every
polling_interval, which is also great in my case. When failed node goes
up, then iSCSI target daemon doesn't start automatically except setup
is fully synced, and in Primary/Primary mode. That way I'm protected
against split brain.

I really don't see any benefits, but just problems, with Primary/Slave
in my case (all the drives are exported via iscsi). So, only doubt I
have is the lack of this kind of setups around, and off course, that
one voice of possible corruption.

Thank you.

|    Jakov Sosic    |    ICQ: 28410271    |   PGP: 0x965CAE2D   |
| start fighting cancer -> http://www.worldcommunitygrid.org/   |

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