[Halld-online] Online Meeting minutes

[David Lawrence]

Hi All,

  Minutes from today’s online meeting have been posted at the following link and are copied below.

https://halldweb.jlab.org/wiki/index.php/OWG_Meeting_13-Jul-2016 <https://halldweb.jlab.org/wiki/index.php/OWG_Meeting_13-Jul-2016>

Regards,
-David


Minutes[edit <https://halldweb.jlab.org/wiki/index.php?title=OWG_Meeting_13-Jul-2016&action=edit&section=6>]

Attendees: David L. (chair), Eugene C., Chip W., Sandy P., Graham H., Dave A., Bryan M., Vardan G., Carl T., Beni Z., Curtis M., Sergey F., Sean D., Mark I.
Announcements[edit <https://halldweb.jlab.org/wiki/index.php?title=OWG_Meeting_13-Jul-2016&action=edit&section=7>]

8 new farm nodes might be here around mid-August
IB switch has now been ordered
* Lots of cables ordered with it. Need to check on cabinet space for when they are delivered (David L. volunteered)
RAID Capacity[edit <https://halldweb.jlab.org/wiki/index.php?title=OWG_Meeting_13-Jul-2016&action=edit&section=8>]

Chip suggested we purchase a system similar to what the CC has recently been purchasing.
This consists of large a large chassis that can hold 44 disks split on 2 backplanes.
Computer is in separate housing with RAID controller connected via cable to disk backplane
System can be run "active-active" where two servers can control both backplanes simultaneously
This provides automatic failover where full disk is still available(at reduced rate) if one server node dies
Consensus that we should go for Chip's "shoestring" option where we buy single server and single chassis with 6TB disks to give us ~135TB additional, usable space
Chip will check with vendor who recently won contract and procurement to see if we can get this through them
Worst case scenario: system is spec'd and put out for bids with short time scale. In either case, we should expect to have the new disk sometime in Sept.
Cost expected to be in $20k range
Tape Library Reconfiguration[edit <https://halldweb.jlab.org/wiki/index.php?title=OWG_Meeting_13-Jul-2016&action=edit&section=9>]
Computer center floor plan will be reconfigured to run at 45 degree angle to current configuration.
Contract constraints currently have this in the middle of the Spring run
Initial schedule has this for one week in first half of March. Vendor though may want to shift it by several weeks. Clarity of schedule will improve as we get closer to activity
Staging disk capacity is plenty for storing several days worth of data at high rate (800MB/s)
Option available to make 2nd copy on another part of staging disk while tape library unavailable.
Possible to use our 72 hour contingency capacity to store 2nd copy for safety though we'd have to delete the 2nd copy if the contingency required activation.
Eugene noted that accelerator cost ~$4-$5 million / week so we have strong interest in ensuring redundancy so that no beam data is lost.
DAQ[edit <https://halldweb.jlab.org/wiki/index.php?title=OWG_Meeting_13-Jul-2016&action=edit&section=10>]

CODA 3.0.6 has been tested and shown to work, though no stress/performance testing done in Hall-D yet
Both ET and direct connection tested and working
f125 Busy mechanism not performance tested in Hall-D
Sergey F. and Cody D. will need to schedule time and coordinate with Alex S. who is currently testing f250 firmware using TS
Jinflux system is now integrated into CODA 3.0.6 and can be accessed via web
(http://claraweb.jlab.org:3000 <http://claraweb.jlab.org:3000/>)
Full java API is available. Could be used to transfer EPICS values on current run conditions to display for easy offsite viewing of current run conditions.
L3 Status[edit <https://halldweb.jlab.org/wiki/index.php?title=OWG_Meeting_13-Jul-2016&action=edit&section=11>]

From Spring 2016 data, roughly 1/4 of L1 events are reconstructable
Original design goal was for 200kHz event rate
Currently approved experiments have maximum of 100kHz
Eugene predicts we will run at 150kHz and L3 will be able to knock that down to about 60kHz to disk
Dave A. noted that with current event size, that will mean 1.6GB/s which will require 2 event streams
Beni suggested we could reduce event size by cutting out-of-time hits when reforming single events
David L. noted that we may also be able to make some gains by dropping Trigger Time or other redundant data that appears in multiple places within the same event.
Quote of the day:
David L. : "That number was just pulled out of the air"
Dave A. : "Better there than from somewhere else."

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