Monday, 30 April 2007

You're only supposed to blow the bloody doors off!

Apart from the Spring HEPiX 2007 meeting last week (which was excellent BTW - I'll do a proper writeup soon) I have been pushing on with Transfer tests. Rather than risk stressing the RAL CASTOR service too much while we work on improving the individual T2 sites, Chris Brew (RAL T2) was v helpful and we've been using their dCache pool (lots of beefy disk servers and some spare capacity) to push out to the T2 sites.

I have knocked up a simple "template" based script for performing the tests now so that I can run serveral sites serially automatically. This means I can set up a screen session to do all sites within a T2 then come back later and look at logs. What we've discovered is that we can set the glite-transfer-cheannel settings much more aggressively than we have been.

Some Examples
* GLA to RALT2 1TB transferred in 3:09:29, Bandwidth = 703.63 Mb/s
* RALT2 to GLA 618G transferred in 2:11:48, Bandwidth = 625.13 Mb/s

As CMS were also doing tests from the T1, we managed to saturate the 1G connection at Imperial College. Whoops. However we also set a new record for HEP Throughput at that site (previous record was ~800Gb/s overnight)