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Re: [EP-tech] Shifting eprints 3.4.3 from RHEL7 to RHEL8

Hi Jens,

I have recently deployed EPrints 3.4.3 on Rocky Linux 8, which is basically the same as RHEL 8.  The only serious issue I found, which may be Rocky Linux 8 specific because it uses MariaDB 10.3 rather than MySQL, is that it by default it enforces that fields that are defined as not null (e.g. eprint_fields.pl field has allow_null=>0) cannot have a default value of null, which EPrints sets as the default value for almost all fields whatever the field setting for allow_null.  I think only bespoke fields may have allow_null set to 0, so generally this will not be a problem.  If you do have bespoke fields with allow_null=>0.  Here is the GitHub issue that contains the patches for fixing this (EPrints 3.4.4 will have these fixes, when released):

https://github.com/eprints/eprints3.4/issues/196

Beyond that,  I cannot remember finding any EPrints specific problems (i.e. where the code is broken, deprecated, etc.) but there were a few things that I needed to do differently to RHEL/Centos 7.

1. There were some missing OS packages (i.e. RPMs) that were not in standard RHEL 8 repositories or EPEL.  See https://wiki.eprints.org/w/Installing_EPrints_on_RHEL/Fedora/CentOS#RHEL_.2F_CentOS_.2F_Rocky_8 for more details.

2. Apache/httpd uses MPM event rather than MPM prefork by default.  This meant that modfifying my Apache performance tuning.  This entailed updating directives like StartServers, ServerLimit, KeepAliveTimeout and adding directives used by event but not prefork (i.e. various thread directives).  EPrints use to have issues running using MPM event rather than MPM prefork but I have not found any problems yet.  However, I have only been running one production repository for just over a month on Rocky Linux 8.  Below is the current performance tuning I am using for a 4GB  2 CPU core VM.  It is probably not perfect but it made a significant improvement to performance after I deployed it.

<IfModule mpm_event_module>
    KeepAlive On
    MaxKeepAliveRequests 250
    KeepAliveTimeout 3

    ThreadsPerChild 12
    ServerLimit 12
    MaxRequestWorkers 144

    StartServers 4
    MinSpareThreads 48
    MaxSpareThreads 144

    MaxConnectionsPerChild 100
</IfModule>

3. Installing ffmpeg if you need to manage video files (e.g. produce different video formats) is a bit more difficult than for to RHEL 7.  However, there are plenty of guides online for installing ffmpeg on RHEL 8.

Regards

David Newman


On 23/05/2022 9:08 am, Jens Witzel via Eprints-tech wrote:
CAUTION: This e-mail originated outside the University of Southampton.

Dear EP-Tech Group

 

Does anyone here have experience with the transition from RHEL7 to RHEL8 and the consequences of the new security policy in combination with Eprints3.4? What pitfalls are to be expected?

 

Every hint is welcome
Thanks
Jens

 

--
Jens Witzel
Zentrale Informatik
Universität Zürich
Stampfenbachstrasse 73
CH-8006 Zürich

mail:  jens.witzel@uzh.ch
phone: +41 44 63 56777
http://www.zi.uzh.ch

 


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