12 April 2017

Beware the Kraken! What happens when you start plotting transfer rates.

FTS transfers  are how the WLCG moves alot of its data. I decided decided to look at what the instantaneous rates within the transfers were.Lines in the log files appear as:

I decided to plot the value of the instantaneous rate with respect to how often this value appeared. Plotting this for 2/18 FTS servers at RAL for ~1month of transfers gives:  

This has been described as a Kraken, the hand of Freddie Kruger, a sea anemone or a leafless tree's branches blowing in the wind . Please leave comments on your own suggestion!!

I also decided to look at the subset of data for FTS transfers to the new CEPH storage at the RAL Tier1 and saw this:

My first thought is that it is similar to the Cinderella castle by Disney.
https://www.pinterest.com/explore/disney-castle-silhouette/ :)

10 April 2017

First look at IPV4/6 Dual mesh perfSonar results for the RAL-LCG2 Tier1

We now have the RAL-LCG2 perfSONAR production hosts dual stacked. I though I would have a look at difference between IPv4 and IPv6 values for throughput rates and round trip times from traceroute  measurements. I first decided to look at the bandwidth measurements between pairs of hosts, and got the following plot:

So I then decided to look at what we get if we compare the ratio of throughput measurements and compare it to the ratio of the round trip times of the traceroute measurements:

03 April 2017

Current storage scope within GridPP

With a new project year upon us, I decided to review which site's storage support is used used by the WLCG VOs, what SRMs are used and the file systems used. On that last part , we now don't just have filesystems but also object stores with the usage of CEPH. Other filesystems are XFS, ZFS, HDFS, Spectrum Scale (or the artist formerly known as GPFS), and Lustre.

In terms of Storage elements/systems we have DPM, dCache, Castor, classic SE, stand alone xrootd, and stand alone gsiftp services. When it comes to the regional T2s and who they are used by, the following helps.

I thought about embedding SE system into the font used for each site, but thought that was too much overlay of information.