<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2//EN"> <HTML> <HEAD> <TITLE>Re: [Linux-cluster] CS4 / U2/U3/U4/ problem about cluster_idgeneration</TITLE> </HEAD> <BODY>  If you stick to the numerical cluster I'd and just use a more robust hash alg you should be fine... -----Original Message----- From: Patrick Caulfield [<A HREF="mailto:pcaulfie@redhat.com">mailto:pcaulfie@redhat.com</A>] Sent: Mon Dec 11 02:42:24 2006 To: linux clustering Subject: Re: [Linux-cluster] CS4 / U2/U3/U4/ problem about cluster_idgeneration Alain Moulle wrote: > Hi > > There is a problem of unicity of cluster_id : > > I have a big configuration with lots of CS4 clusters in pairs. > The cluster_names are such as : > iocell1 for first pair > iocell2 for 2nd one > ... > > Naming is automatic as there are lots of HA node pairs. > > ok, now let's take the cluster iocell13 and iocell21 and the > algorythm in cnxman.c : > > static uint16_t generate_cluster_id(char *name) > { > int i; > int value = 0; > > for (i=0; i<strlen(name); i++) { > value <<= 1; > value += name[i]; > } > return value & 0xFFFF; > } > > For iocell13 : > [[[[[[["i"/0x69]*2+"o"/0x6f]*2+"c"/0x63]*2+"e"/0x65]*2+"l"/0x6c]*2+&qu > ot;l"/0x6c]*2+"1"/0x31]*2+"3"/0x33 == 0x6895 == 26773). > > and for iocell21: > [[[[[[["i"/0x69]*2+"o"/0x6f]*2+"c"/0x63]*2+"e"/0x65]*2+"l"/0x6c]*2+&qu > ot;l"/0x6c]*2+"2"/0x32]*2+"1"/0x31 == 0x6895 == 26773). > > so we have two identical cluster_id for two different cluster > (based on cluster names). > > So there is problem because a node denies/un-acks the joins since the same > "cluster-id" is claimed but with an other Cluster name also checked > > I've checked that algorythm has not been modified since U2 , and therefore > the problem remains for sure with U4. > > Any idea to solve it for sure ? Not really, sorry. It's unlikely to change in the future for RHEL4 because that would break backwards compatibility. -- patrick -- Linux-cluster mailing list Linux-cluster@redhat.com <A HREF="https://www.redhat.com/mailman/listinfo/linux-cluster">https://www.redhat.com/mailman/listinfo/linux-cluster</A> </BODY> </HTML>