[Halld-offline] Software Meeting Minutes, November 26, 2019

Fri Nov 29 17:32:17 EST 2019

Please find the minutes here 
<https://halldweb.jlab.org/wiki/index.php/GlueX_Software_Meeting,_November_26,_2019#Minutes> 
and below.

    GlueX Software Meeting, November 26, 2019, Minutes

Present:

  * *CMU: * Naomi Jarvis
  * *JLab: * Thomas Britton, Mark Ito (chair), Igal Jaegle, David
    Lawrence, Keigo Mizutani, Justin Stevens, Simon Taylor, Beni Zihlmann

There is a recording of his meeting <https://bluejeans.com/s/TdSMk/> on 
the BlueJeans site. Use your JLab credentials to access it.

      Announcements

 1. New version set: version_4.11.0.xml
    <https://mailman.jlab.org/pipermail/halld-offline/2019-November/003819.html>
    The latest set of default version was released on November 19.
 2. *"atime" enabled on the work disk (/work/halld)*. Until yesterday,
    files on the work disk have not had their access times updated by
    the filesystem in order to boost performance. Yesterday atime
    updates were turned on on /work/halld. to be precise "relatime," a
    ZFS feature was enabled. Atimes less than 24 hours in the past are
    left alone. Having this feature will help us distinguish between old
    files that have been used recently and those that have gone unread
    for a long time.
 3. *Work disk still full*. The work disk is at 98% full see the plot
    below for recent history and follow this link
    <https://halldweb.jlab.org/disk_management/work_report.html> to see
    a report on work disk usage.

<https://halldweb.jlab.org/wiki/index.php/File:Work_disk_3.png>
Work Disk Usage

 1. *Mirrors of CCDB SQLite Files*. Thomas pointed out that there are
    still some MCWrapper users out there using old versions that are
    pointing their JLab Farm jobs to the SQLite files on the work disk.
    The work disk has a known pathology with file locking that causes
    these jobs to hang. He asked that those files be deleted.
      * David suggested that we remove some legacy magnetic field maps
        from the CCDB. They were kept in to allow old code to access
        them there, but that code is now many years old. Field maps are
        now accessed as a JANA Resource. Deleting them will save a lot
        of space in the database, and in particular in the SQLite files
        generated from MySQL, perhaps a factor of two or more. Mark will
        look into doing this.
      * Added in press: the deed was done. See this email message from
        Mark
        <https://mailman.jlab.org/pipermail/halld-offline/2019-November/003824.html>
        for more details.

      Review of Minutes from the Meeting on October 29

We went over the minutes 
<https://halldweb.jlab.org/wiki/index.php/GlueX_Software_Meeting,_October_29,_2019#Minutes>. 

Beni emphasized the issue of upgrading from Python 2 (P2) to Python 3 
(P3). [Added in press: he refers us to this link 
<https://sebastianraschka.com/Articles/2014_python_2_3_key_diff.html> on 
the subject].

  * We run with a mixture of the two, scattered all over the source code
    base.
  * David pointed out last time that conversion from P2 to P3 mostly
    consists of changing "print" statements.
  * He also told us that Python 2 official support ends in January 2020.
  * He has been using #!/usr/bin/python3 to identify scripts that are
    meant for the P3 interpreter.
  * And SCons uses P2 at present.
  * P2 vs. P3 differs from C++ vs. C++11 in that the compiler choice is
    made before building the entire code base and so builds fail with
    the wring choice. Whereas the interpreter choice is important only
    at run-time allowing for more flexibility. In addition, the choice
    of interpreter can be made explicitly on the command line, e.g.,
    |/path/to/python script.py|.

The clear path forward is still not visible.

      Review of the HDGeant4 Meeting on November 19

We went over the minutes 
<https://halldweb.jlab.org/wiki/index.php/HDGeant4_Meeting,_November_19,_2019#Minutes>. 
There were no significant comments beyond those already in the minutes.

      Accidental scaling factors in DSelectors

The scaling factors, produced by Beni and Richard Jones, that correct 
for less-than-100% duty factor of the machine are now available in the 
CCDB 
<https://mailman.jlab.org/pipermail/halld-offline/2019-October/003801.html> 
thanks to Sean Dobbs.

      New CentOS 7.7 Nodes on the JLab Farm

Beni brought up the subject of using the new nodes on the farm, 
announced on November 15 
<https://mailman.jlab.org/pipermail/jlab-scicomp-briefs/2019q4/000229.html> 
running with CentOS 7.7. He was not able to get a successful build on 
ifarm1802 (recently upgraded to 7.7); there was a problem with the MySQL 
libraries. Justin pointed out that if we get a public build going on 
these nodes we can use them for monitoring launches to avoid competition 
with other tasks. Mark will look into a build on this platform.

      New Translation Tables for Fall 2019

Justin reported that new translations tables are on the way. They 
incorporate the upgraded TOF, the GEM/TRD channels, and a few new 
DIRC-related channels.

      Using Google Groups for Email Forums

We briefly discussed some of the problem with using Google Groups for 
email discussions. There are many positive aspects which motivated the 
switch in the first place, but down-sides have been noted:

  * Use of non-google emails is a bit complicated and has limitations
    (in particular where authentication is needed).
  * The group use of a single account to own the groups, accessible to
    the entire Collaboration is running into occasional security
    measures from Google.
  * Authenticated web access from some universities (including CMU)
    using Google Suite is an on-going problem.

CLAS12 and the Geant4 Collaborations are moving to a product called 
Discourse <https://discourse.org/>. Trello <https://trello.com> was 
mentioned as another options. We probably would have to lobby, in 
concert with other groups at the lab, in order to get IT Division to pay 
for a site license for any of these products. This is not a crisis at 
this point, but it is something for us to think about.

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  * This page was last modified on 29 November 2019, at 17:29.

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