Hello. We are using the Redhat load balancing add-on that comes on RHEL
6. We want to have highly available MySQL; we have two co-master MySQL
servers that replicate to each other. MySQL says that that updates
should only come in to one of these at a time because of the possibility
that conflicting updates arrive at each server simultaneously. So we
want to use LVS to direct all traffic to one of the co-masters (call it
mysql01) except when it is down, in which case to direct all traffic to
the other one (call it mysql02).
We thought this requirement would be common enough to be addressable via
stock LVS capability. Our initial thought was to set the weight of
mysql01 to 1 and mysql02 to 0. However, new connections still went to
mysql02. We discovered
http://archive.linuxvirtualserver.org/html/lvs-users/2008-10/msg00101.html
and set the /etc/sysctl.conf parameters, also tried setting them via the
equivalent files in /proc/sys/net/ipv4/vs/, still connections went to
both servers even when we waited beyond the persistence timeout of 600s.
Because of this behavior, we are not able to test whether our approach
is sound to begin with; i.e., if mysql01 goes down will traffic be
redirected to mysql02 even though its weight is 0? We thought that if
it was the only machine up in its group the weight would not matter.
But would like to know if that assumption was accurate also.
Here's that section of our lvs.cf:
virtual MySQL {
active = 1
address = 192.168.185.115 eth0:6
vip_nmask = 255.255.255.0
fwmark = 3306
port = 3306
persistent = 600
use_regex = 0
load_monitor = none
scheduler = wlc
protocol = tcp
timeout = 6
reentry = 15
quiesce_server = 0
server MySQL01 {
address = 192.168.185.51
active = 1
port = 3306
weight = 1
}
server MySQL02 {
address = 192.168.185.52
active = 1
port = 3306
weight = 0
}
}
Would appreciate any advice. Thanks.
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