[3dem] Falcon II uses only half of the 1Gb/s bandwidth.

Sargis Dallakyan sargis at nysbc.org
Tue Oct 16 18:02:08 PDT 2018

Just to break an ice on this topic, what kind of disk is on a PC that you are transferring the data to? It's been mentioned in one of the latest DDN videos<https://www.youtube.com/watch?v=NabTsYl_mIQ&list=PLohLhg8SlVmbG8W_TFIWQFFhg1LJ0-xf1> that no matter how big is your bandwidth, you'll be disk IO limited if your storage can't support enough IOPS (https://en.wikipedia.org/wiki/IOPS). Maybe getting an SSD might solve this bottleneck, if I understand the problem correctly.

Sargis Dallakyan, PhD - Systems Administrator
National Resource for Automated Molecular Microscopy
Simons Electron Microscopy Center
New York Structural Biology Center

Date: Tue, 16 Oct 2018 16:15:00 +0300
From: Eugene Pichkur <eugene.pichkur at gmail.com>
To: 3dem at ncmir.ucsd.edu
Subject: [3dem] Falcon II uses only half of the 1Gb/s bandwidth.
        <CAJJJP0=9cSHBRxKLOQkaYmqvg3X6Ym4iq-DT_oMCvNYERErr4w at mail.gmail.com>
Content-Type: text/plain; charset="utf-8"

Hello 3DEM community,

We've noticed that our Falcon II uses only half of the 1Gbps bandwidth to
transfer data from the Camera Support Rack to the Microscope PC (I've
attached a screenshot to illustrate the issue).

Microscope PC runs Windows 7 and we are able to get the full frame rate
(20fps) from the detector, however, it takes ~20s to transfer a typical
movie (40frames, 1.2GB) to the PC which is a very frustrating bottleneck.

Both Falcon II and Ceta are connected through the same 1Gb switch (HPE
OfficeConnect 1420 24G 2SFP), so my guess is that the bandwidth is split
50/50. However, during data collection only Falcon II is used which makes
this limitation pointless, not to mention that Falcon II and Ceta can't be
used simultaneously.

Does anyone have a workaround or any info on the topic?

Thanks in advance,
Eugene Pichkur

National Research Centre ?Kurchatov Institute?
Akademika Kurchatova, 1, Moscow, Russia, 123098
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