[DRBD-user] Bug? GI UUIDs differ by 1

Roland Kammerer roland.kammerer at linbit.com
Mon Nov 2 13:21:07 CET 2015

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


On Mon, Nov 02, 2015 at 01:00:03PM +0100, Veit Wahlich wrote:
> Hi,
> 
> I am observing a quite strage behaviour:
> 
> The generation identifier UUIDs on my nodes differ although the volumes
> are connected and reported in-sync (in fact they are really in-sync, I
> ran a verify).
> 
> Regarding to https://drbd.linbit.com/users-guide/s-gi.html this should
> not happen.
> 
> I find it quite odd that the differences in UUID was always only 1 so
> far:
> 
> Here GIs from node A:
> 
> [root at nodea:~]# drbdadm get-gi all
> 749E0550B4C8120C:0000000000000000:B36328481DC19155:B36228481DC19155:1:1:0:1:0:0:0
> CA23BF5B6198E2A2:0000000000000000:37EC37F7420D2057:37EB37F7420D2057:1:1:0:1:0:0:0
> AD2A6DB42BD2E1E6:0000000000000000:8FF18D07624D26DA:8FF08D07624D26DA:1:1:0:1:0:0:0
> 
> [root at nodeb:~]# drbdadm get-gi all
> 749E0550B4C8120C:0000000000000000:B36328481DC19154:B36228481DC19155:1:1:0:1:0:0:0
> CA23BF5B6198E2A2:0000000000000000:37EC37F7420D2056:37EB37F7420D2057:1:1:0:1:0:0:0
> AD2A6DB42BD2E1E7:0000000000000000:8FF18D07624D26DA:8FF08D07624D26DA:1:1:1:1:0:0:0
> 
> Here for the 3rd volume, the currend GI UUID differs by 1.
> For the 1st and 2nd volume, the younger history GI UUID differs by 1.
> 
> Is this in any way an expected behaviour?

Hi,

it is expected behavior, don't worry, everything is fine. The lowest bit
is used to encode the role (1 == primary, 0 == secondary IIRC).

Regards, rck



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