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Re: [lvs-users] MySQL HA - timeouts on "complex queries" ?

To: "LinuxVirtualServer.org users mailing list." <lvs-users@xxxxxxxxxxxxxxxxxxxxxx>
Subject: Re: [lvs-users] MySQL HA - timeouts on "complex queries" ?
From: Dan Yocum <yocum@xxxxxxxx>
Date: Thu, 11 Oct 2007 11:25:06 -0500
Hm.  I'm interested in the outcome of this discussion as I've got a 
similar setup with circular mysql replication but without the RR DNS.

Jessie - are you using any persistence for the mysql connections?  If 
so, how long?

Dan


Jessie wrote:
> Hi Joe,
> 
> 
> 
> On Oct 11, 2007, at 5:19 AM, Joseph Mack NA3T wrote:
> 
>> On Wed, 10 Oct 2007, Jessie wrote:
>>
>>> Hi everyone,
>>>
>>> I've tried two different approaches on LVS-DR to get a HA MySQL
>>> system going.
>>> * LVS-DR using two realserver definitions
>>> * LVS-DR using one realserver and one sorry server (per HOWTO)
>>>
>>> We have two MySQL 5 servers in master-master mode (copper & olive)
>>>
>>> We have two LVS-DR load balancers, (lb2 and lb3)
>>>
>>> Each LVS-DR has a vip hostname: (tea, soda)
>> I assume an "LVS-DR" is a director, but I don't know why you
>> have two VIPs.
> 
> 1 VIP per director
> 
> lb2 and lb3 are LVS-DR directors
> 
> on lb2 is a VIP called tea
> on lb3 is a VIP called soda
> 
> 
>>> lb2:
>>> tea:3306
>>>       copper (realserver)
>>>       olive (sorry server)
>>>
>>> lb3:
>>> soda:3306
>>>      olive (realserver)
>>>      copper (sorry server)
>>>
>>>
>>> 'mysql.example.org' has two DNS A records (tea,soda) and round robins
>>> which VIP/LB to hit.
>> so this isn't really an LVS then?
>>
> 
> 'mysql' is a DNS hostname that points to two VIPs on two LBs for HA
> 
> each VIP has a different Mysql-Server active (remember this is a  
> master-master replication)
> 
> 
> 
> 
>>> connecting to 'copper' is fine
>> directly? from where?
>>
> 
> 
> "The internet" (ie outside the director IP subnet)
> 
> 
> 
>>> connecting to 'olive' is fine
>>> connecting to 'tea' is NOT fine with the apps above, but manual mysql
>>> queries *seem* OK.
>>> connecting to 'soda' is NOT fine with the apps above, but manual
>>> mysql queries *seem* OK.
>>> connecting to 'mysql' is NOT fine with the apps above, but manual
>>> mysql queries *seem* OK.
>> have you shown that LVS is working by testing with a simple
>> service like telnet?
>>
> 
> 
> I have around 50 VIPs across two directors working. I can establish a  
> socket to the mysql server through LVS and perform simple
> mysql queries. I can do the same going directly to the realserver ip.  
> What fails are large/complex SQL queries THROUGH the director/VIP
> 
> 
> 
>>> I've tried using just one LVS-DR server and it didn't make
>>> any difference. I cannot produce any problems using LVS
>>> via a manual mysql query through LVS All production apps
>>> when pointed to an LVS host, will occasionally work, and
>>> other times just timeout.
>>>
>>> The firewall on all the systems looks clean
>> don't install firewall rules till you have the LVS working
>>
> 
> I turned it off -- no diff.
> 
> 
> 
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-- 
Dan Yocum
Fermilab  630.840.6509
yocum@xxxxxxxx, http://fermigrid.fnal.gov
Fermilab.  Just zeros and ones.


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