Does OTRS support Load Balancing?

[mustu]

Hi,

I've setup OTRS 3.0.10 on two physical servers. First server is the APP server which holds the OTRS application and Second server is our DB server. Database is also being replicated in a third backup database server.

Now, I want to introduce another APP server and load balance my requests on both servers. Unfortunately I'm not able to load balance my requests to both servers due to limitation in OTRS. The limitation I've found is that OTRS does keeps the LATEST generated ticket number in a text file on system /opt/otrs/var/log/TicketCounter.log. Even in case of failure of primary APP server I can't do the failover automatically. That's because on primary server the text file holds the latest ticket number let's suppose it's 200. The secondary server's TicketCounter.log won't have the sane value ofcourse. If I just put traffic on teh second server and the TicketCounter.log file have a value of 100 then it will corrupt my already existing tickets and will start tying create ticket with number 100 and so on.

So for an APP server failover I have documented that before even putting traffing on the secondary server I need to get the latest ticket value from the database [ select max(tn) from ticket; ] and put that value in the TicketCounter.log file and then put on the traffic.

Is there any solution ? Isn't OTRS developed with keeping load balancing in mind? Is there any way we can scale OTRS performance and availability by introducing multiple APP servers ?

[Andre Bauer]

You could try to replicate the OTRS filesystem via DRBD. http://www.drbd.org/users-guide/s-dual- ... -mode.html

[BIG_jan]

copy the file to an external server and change the sysconfig
Ticket::CounterLog - <OTRS_CONFIG_Home>/var/log/TicketCounter.log

set all servers to the same log and hope that they don't block eachother

[mustu]

Isn't there any way to fetch the Ticket::CounterLog value from DB instead of a text file on system?

[jojo]

no

[MichaelR]

I'm sure you could write some Perl that would fetch it from the DB instead...

[mustu]

can anyone verify that if we don't use the email feature to open ticket and only use customer.pl then the TicketCounter.log is not used?

[jojo]

Ticket Counter log will always used on new ticket creation

[mustu]

JoJo,

As I discussed in the thread (http://forums.otrs.org/viewtopic.php?f=53&t=13543) The Ticket Counter can be escaped by NOT using the Auto-Increment method. Like the DataChecksum method doesn't depends on that counter text file.

Do you believe in this way we have eliminated dependency on anything resident on file-system and can run two or more OTRS app servers parallel connected with a single database?

[jojo]

The Config.pm needs to be the same and the ZZZAuto.pm which is written by Sysconfig needs to be shared. Also Cron Jobs are only allowed to run on one system

[aliumair]

is it possible that i place the different number on TicketCounter.log, in one instance TicketCounter.log have value of 2000 and second instance TicketCounter.log have value of 3000, when 1st instance reach till 3000 then again i create a gap of 1000 value in both instance? is it have any side effects?

Actually we want load balancing with two App server but same DB server for both of them, if i use gap between ticket number of these two Apps. is it have any issue ??

Kindly guide me if any alternative solution is there....

Waiting for your response.

[jojo]

A gap won't work in the logfile.

You should have a fast shared filesystem which supports locking for this

[aliumair]

jojo thanks for replying, Can you explain me fast shared system how help me?? is there any reference material or any thing? please share steps with me, i really thankful to you.

[ferrosti]

jojo is talking about a network file system, like cifs or nfs. One needs to make sure that file locking applies through the file system, since only one process is allowed to write to the file.
You need to make sure that the network file system you choose supports native file locking.