[Linux-cluster] Split-brain with DRBD active-active + RHCS
jayesh.shinde at netcore.co.in
Tue Mar 15 12:13:14 UTC 2011
Hi All ,
I don't have SAN with me , so I want to build the 2 node DRBD active
active for mysql & http resource ( i.e /dev/drbd2 & /dev/drbd3 in my
case) with RHCS .
I configured the require setup from
http://sourceware.org/cluster/wiki/DRBD_Cookbook and from DRDB links.
From last 1 week I am testing the same scenario in 2 XEN vms with
kenel 2.6.18-128.el5xen , Every thing is working fine , like mysql and
http services move from one server to other etc... But not working
correctly when it get fence ( i.e when n/w fail on of the node).
*I am facing the split-brain problem. * I search a lot in google and
mailling list but don't found the proper correct solution and suggestion.
For Fence testing I am doing following.
1) On node1 http service is running with /dev/drbd2
2) On node2 mysql service is runing with /dev/drbd3
At this movement the DRBD primary-primary status is working correctly.
3) Now On node2 When I stop n/w service manually by "service network
stop" then within 3-5 sec. node2 get fence properly and mysql service
get switch on node1 properly.
4) After fencing when node2 come up , then I am facing the DRBD
split-brain issue with node1 and node2.
My questions :--
1) Why DRBD Split brain is not coming when I reboot or shutdown or
destroy the machine by xm command
i.e "xm reboot <node1/node2>" OR xm shutdown
<node1/node2> OR xm destroy <node/node2>
2) Why the DRBD split brain issue come at the time of fencing node only ?
3) Is the combination of DRBD active-active + RHCS is stable ? and
Because one of the below mailling list I found it's workable solution
4) In fencing Is there any extra setting require for such combination ?
5) Do I need to use any custom fencing logic ?
6) Any one using such "*DRBD active-active + RHCS*" setup in Live
without split brain issue ?
Please guide and suggest on the same.
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