[DRBD-user] Dose drbd 0.8.0 and drbd 0.7.4 work together ?

Helmut Wollmersdorfer helmut.wollmersdorfer at gmx.at
Wed Jun 1 14:12:44 CEST 2005

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

Holger Wöhle wrote:

> We are using a two node cluster. 
> At the moment only one node is running SuSE 9.2 with drbd 0.7.4 in
> standalone mode.
> The inactive node runs SuSE 8.1 . Now we want to rebuild that one and think
> about SuSE 9.3 with drbd 0.8.0 .
> Does those two vesions work together ? Or may it be better to use SuSE 9.2
> too on the other node ?

If two versions of DRBD work together can easily be seen from API and 
PROTOCOL version.

# cat /proc/drbd
version: 0.7.10 (api:77/proto:74)

See http://www.drbd.org/releases.html
Note: "api" version denotes compatibility level to the user space tool 
drbdsetup. Identical "proto" number means these are compatible on the 
wire, so to upgrade you could connect two different releases with the 
same proto version.

Since drbd 0.7.0, two drbd releases with adjacent api versions will be 
able to talk with each other, which makes rolling upgrades (no service 
downtime) possible.

At http://svn.drbd.org/drbd/branches/drbd-0.7/ChangeLog you can see that
'proto:74' is the same from 0.7.0 to 0.7.11.

I don't know the 'proto' of 0.8.x, but I would guess it incompatible 
with 0.7.x, as 0.8.x introduces new features.

Besides 0.8.x is not released officially by DRBD developers.

Best choice would be 0.7.10 or 0.7.11 on both nodes. AFAIR 0.7.5 was the 
first version of 0.7.x worth the classification "very stable". Release 
of 0.7.10 happend at 31st Jan of 2005 and no serious bugs are known 
during 4 months - IMHO "rock solid".

Helmut Wollmersdorfer

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