[mod_cluster-issues] [JBoss JIRA] (MODCLUSTER-636) When setting PersistSlots to On, EAP node can not rejoin mod_cluster due to java.lang.IllegalArgumentException

[Alex Cai (JIRA)]

    [ https://issues.jboss.org/browse/MODCLUSTER-636?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13507693#comment-13507693 ] 

Alex Cai commented on MODCLUSTER-636:
-------------------------------------

[~jfclere] We got the following feedback from customer regarding ThreadsPerChild:
--------
1. We know that ThreadsPerChild is changed frequently when using apache.
- Does it mean that we should not change the ThreadsPerChild value, if we use the PersistSlots On option.
- web server administrator said that there was a problem when only restarting the web server, and after tracking what he did, he modified the 00-mpm.conf file and confirmed that he restarted it.
- So, to reproduce, 00-mpm.conf was modified and tried to test, and reproduced more than a few times.

2. We modified the ThreadPerChild option to increase the number of threads per apache child process.
- It is set to a low value before the load test, and it is set to a high value in the load test.
- We also adjusted these options to reduce the number of child processes to find the appropriate values, and to increase the number of threads in each child process.
- If you set it to a value greater than or equal to 64, we know that it usually should be set the ThreadLimit and ThreadsPerChild values the same.
--------

- Does this match your ananlysis?
- Could you please share more details regarding why changing ThreadsPerChild with PersistSlots On will cause the problem? We will need to let customer understand the reason.

Thanks


> When setting PersistSlots to On, EAP node can not rejoin mod_cluster due to java.lang.IllegalArgumentException
> --------------------------------------------------------------------------------------------------------------
>
>                 Key: MODCLUSTER-636
>                 URL: https://issues.jboss.org/browse/MODCLUSTER-636
>             Project: mod_cluster
>          Issue Type: Bug
>          Components: Native (httpd modules)
>    Affects Versions: 1.3.5.Final
>         Environment: * JBCS httpd 2.4.23 SP2
> * mod_cluster: 1.3.5
> * EAP: 7.0.8
>            Reporter: Alex Cai
>            Assignee: Jean-Frederic Clere
>
> Customer set 'PersistSlots On' and sometimes the jboss eap node could not rejoing into mod_cluster due to java.lang.IllegalArgumentException
> When they got this exception, they have to delete every cache files then restart httpd and jboss for join correctly.
> Customer tried the below actions:
> 1) apache stop -> delet manager.* files in the mod_cluster directory -> apache start 
> - this action could cause http 503 error
> or
> 2) pre-backup the all files(normal files before issue) in the mod_cluster directory. when the issue occure, apache stop -> restore manager.* files from backuped files -> apache start
> - no http 503 error
> Please see the case for more details:
> https://access.redhat.com/support/cases/01986243



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