<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=utf-8">
</head>
<body text="#000000" bgcolor="#FFFFFF">
<p>Folks,</p>
<p>Please find the minutes below and at
<a class="moz-txt-link-freetext" href="https://halldweb.jlab.org/wiki/index.php/GlueX_Offline_Meeting,_September_20,_2017#Minutes">https://halldweb.jlab.org/wiki/index.php/GlueX_Offline_Meeting,_September_20,_2017#Minutes</a>
.</p>
<p>_______________________</p>
<p>
</p>
<div id="globalWrapper">
<div id="column-content">
<div id="content" class="mw-body" role="main">
<h2 id="firstHeading" class="firstHeading" lang="en"><span
dir="auto">GlueX Offline Meeting, September 20, 2017, </span><span
class="mw-headline" id="Minutes">Minutes</span></h2>
<div id="bodyContent" class="mw-body-content">
<div id="mw-content-text" dir="ltr" class="mw-content-ltr"
lang="en">
<p>Present:
</p>
<ul>
<li> <b> CMU: </b> Curtis Meyer</li>
<li> <b> FSU: </b>: Brad Cannon, Sean Dobbs</li>
<li> <b> Glasgow: </b>: Peter Pauli</li>
<li> <b> JLab: </b>: Alex Austregesilo, Thomas
Britton, Eugene Chudakov, Sebastian Cole, Sergey
Furletov, Mark Ito (chair), David Lawrence, Justin
Stevens, Simon Taylor, Beni Zihlmann</li>
</ul>
<p>There is a <a rel="nofollow" class="external text"
href="https://bluejeans.com/s/M4QaP/">recording of
this meeting</a> on the BlueJeans site. Use your JLab
credentials to access it.
</p>
<h3><span class="mw-headline" id="Announcements">Announcements</span></h3>
<ol>
<li> <a rel="nofollow" class="external text"
href="https://mailman.jlab.org/pipermail/halld-offline/2017-September/002938.html">Automatic
updates of ccdb.sqlite on OASIS</a>. Mark started a
system to keep the CCDB up-to-date for grid jobs.
There are still a few authentication wrinkles to iron
out of the system.</li>
<li> <a rel="nofollow" class="external text"
href="https://halldweb.jlab.org/talks/2017/HDvis2/js/event.html">HDvis
progress</a>. Thomas summarized recent progress. See
the recording starting at 6:50 for the visuals.
<ul>
<li> Recent work has been on performance. Overall, a
factor of 3-5 in speed has been realized.</li>
<li> All of the BCAL modules were rendered before,
now just the hit ends are shown.</li>
<li> Only the hit bars of the TOF are shown.</li>
<li> The FCAL no longer appears cut in half when
viewed from certain angles.</li>
<li> There is a play/pause button now.</li>
<li> In the future, there will be a time-selecting
slider bar.</li>
</ul>
</li>
</ol>
<h3><span class="mw-headline"
id="Review_of_minutes_from_the_last_meeting">Review of
minutes from the last meeting</span></h3>
<p>We went over the <a
href="https://halldweb.jlab.org/wiki/index.php/GlueX_Offline_Meeting,_September_6,_2017#Minutes"
title="GlueX Offline Meeting, September 6, 2017">minutes
from September 6</a>; there was no significant
discussion.
</p>
<h3><span class="mw-headline"
id="Report_from_the_JLab_Computing_Steering_Committee_Meeting">Report
from the JLab Computing Steering Committee Meeting</span></h3>
<p>Chip Watson gave a summary of SciComp activities at the
meeting on August 23. See <a rel="nofollow"
class="external text"
href="https://halldweb.jlab.org/talks/2017/IT%20Steering%20Committee%20Sept%202017%20SciComp.pptx">his
slides</a> for the details. Some highlights directly
relevant for us:
</p>
<ul>
<li> A new work disk server is coming soon.</li>
<li> An <a rel="nofollow" class="external text"
href="http://www.nersc.gov/">NERSC</a> share has
been granted to explore using that facility to augment
computing capability beyond that of the JLab farm.</li>
</ul>
<p>Sean asked if SciComp was going to provide tools to
help use this new resource. Mark replied that the
SciComp is willing to commit manpower to development of
tools, but that has not started yet. Related to this
David reported that his Lab-Directed Research and
Development (LDRD) proposal has been approved. This
effort to develop a next-generation JANA also involves
bench-marking the new system at NERSC. He has been
awarded a share, independent of the one that Chip
announced. That effort will give Hall D some in-house
experience running on this new (to us) platform.
</p>
<h3><span class="mw-headline" id="Computing_Resources">Computing
Resources</span></h3>
<p>Alex brought up two important issues.
</p>
<h4><span class="mw-headline" id="Analysis_of_REST_Files">Analysis
of REST Files</span></h4>
<p>Alex reported that there are a lot of jobs on the farm
these days from individual GlueX collaborators running
over REST files. There are no production launches in
progress, so at present they do not cause conflict, but
there is potential for conflict in the future. We should
encourage use of the clusters at collaboration
institutions for these tasks, like is being done at CMU
and IU.
</p>
<p>Sean pointed out that the analysis launches have been
the most efficient way to go through the REST data in a
way that benefits the greatest number of individual
analyses. After some discussion we decided to institute
monthly analysis launches, more if there is a pressing
demand, to go through the REST data. [Added in press:
launches will be on the last Friday of every month. The
next one will therefore be on Friday, September 29. Mark
your calendar.]
</p>
<h4><span class="mw-headline" id="Cache_Disk_Space">Cache
Disk Space</span></h4>
<p>Alex reported that the pin quota on our cache disk has
been reduced recently by SciComp, down to 160 TB from
350 TB[?]. This has caused REST data to be deleted. The
lack of spinning REST data has in turn slowed the
progress of the individual-collaborator jobs, mentioned
in the previous section, due to jobs having to wait on
tape retrieval of input files.
</p>
<p>Mark reminded us that in our original plans we had a
rough guess of disk space needed for reconstructed data
of 500 TB. The plan was to put the data on work where we
can control when data goes on the disk and when it comes
off. Now that we have the pinning mechanism, the cache
disk seems a much more natural place since all of the
data is on tape and the cache disk is a partial mirror
of tape. And in fact we probably underestimated the
amount needed. Intermediate term, 1 PB seems a more
reasonable number. Although near-term, disk space is
budget limited, we should think about upping our
request.
</p>
<p>Other points:
</p>
<ul>
<li> Alex told us that the REST data for Spring 17 alone
is 120 TB. Spring 16 is not much smaller than that.
Spring 17 REST nearly saturates the current pin quota
which is already maxed out with analysis launch
products.</li>
<li> When raw data is processed, those files are charged
against our pin quota. We cannot unpin them when the
jobs finish; that is under control of the farm system.
At certain points in time this can be a large amount
of data.</li>
<li> When unpinned data are deleted, it is done on the
basis of modification time (time since the file was
put on disk) and not access time (time since the file
was last read). It would be more efficient if access
time could be used. Frequently used files could hang
around, eliminating the need to re-fetch them from
tape.</li>
</ul>
<p>This discussion highlighted the need for a more
detailed analysis of disk requirements. We should review
previous estimates and understand changes called for now
that we have real experience. Justin pointed out that we
are planning another reconstruction pass on the raw data
in a few weeks (with corrected FCAL calibration, updated
CDC dE/dx calculations, updated TOF timing constants,
etc.) and we should look ahead to what that will
require.
</p>
<h3><span class="mw-headline"
id="Review_of_recent_pull_requests">Review of recent
pull requests</span></h3>
<p>We went over the <a rel="nofollow" class="external
text"
href="https://github.com/JeffersonLab/sim-recon/pulls?q=is%3Aopen+is%3Apr">the
pull requests</a> since the last meeting.
</p>
<p>Richard Jones checked in a change that simulates
Cerenkov radiation in the FCAL light guides. David
reminded us that he has seen this effect for particles
that pass through the lead glass. He also noted that now
that it is in the simulation, there needs to be an
effort to incorporate it in mcsmear as an effective
contribution to the "energy" for these particles.
</p>
<h3><span class="mw-headline"
id="Review_of_recent_discussion_on_the_GlueX_Software_Help_List">Review
of recent discussion on the GlueX Software Help List</span></h3>
<p>We looked at the <a rel="nofollow" class="external
text"
href="https://groups.google.com/forum/#%21forum/gluex-software">list</a>.
There was no significant discussion.
</p>
<h3><span class="mw-headline" id="Action_Item_Review">Action
Item Review</span></h3>
<ol>
<li> Institute a monthly Analysis Launch. (Alex)</li>
<li> Review and update the disk resource estimate.
(Mark)</li>
<li> Incorporate light-guide-induced Cerenkov radiation
in mcsmear. (TBA)</li>
</ol>
</div>
<div class="printfooter">
Retrieved from "<a dir="ltr"
href="https://halldweb.jlab.org/wiki/index.php?title=GlueX_Offline_Meeting,_September_20,_2017&oldid=83723">https://halldweb.jlab.org/wiki/index.php?title=GlueX_Offline_Meeting,_September_20,_2017&oldid=83723</a>"</div>
</div>
</div>
</div>
<div id="footer" role="contentinfo">
<ul id="f-list">
<li id="lastmod"> This page was last modified on 20 September
2017, at 20:36.</li>
</ul>
</div>
</div>
</body>
</html>