Frontier T0 Squids overload of August 7th, 2014



A set of workflows related to Cosmics data was set to run in the Agile Infrastructure at CERN (T2_CH_CERN_AI), which utilices the T0 squids cmst0frontier{1,2} as specified in its site-local-config.xml. An overview of the spill-over activity from the squids onto the central Launchpads can be seen below:

Given the completeness of a squid log and the sheer amount of queries a Frontier squid usually undergoes, the statistics to be reported in this document focus on specific time spans, over which the logs are aggregated in order to extract the most relevant patterns. The chosen time spans (CET time zone) at the time of this writing were:

  1. Just before Noon: From 11:00 AM to 12:00 PM
  2. Early Evening: From 6:00 PM to 7:00 PM

Situation under heavy load: Just before Noon

Since on this day the site-local-config.xml included the clause for the backup proxies cmsbpfrontier{1,2}, the traffic statistics for the T0 squids and the backup proxies are compared.

Machines Hits Size
T0 squids

The biggest shares of the load (measured by data transferred) per Frontier ID (which traces the kind of job that made the Frontier query) is shown below:

Query type Frontier ID Share [%]
PromptProd wmagent_PromptReco_Run224187_MinimumBias 87.94
wmagent_PromptReco_Run224409_Cosmics 3.52
wmagent_PromptReco_Run224413_MinimumBias 1.69
wmagent_PromptReco_Run224259_MinimumBias 1.62
wmagent_PromptReco_Run224471_Cosmics 1.56
Others 3.68
FrontierProd CMSSW_7_0_1 40.98
wmagent_jbadillo_ACDC_BTV-Fall13dr-00210_T1_US_FNAL_MSS_00084_v0_castor_tsg_140806_141814_7313 36.20
wmagent_alahiff_BTV-Spring14dr-00120_T1_US_FNAL_MSS_00120_v0_castor_140806_132554_7742 4.35
CMSSW_7_2_X_2014-08-07-0200 3.52
CMSSW_7_2_DEVEL_X_2014-08-07-0200 2.37
Others 12.58

Regarding the origin regions of the queries, here is the distribution of them (again, measured by data transferred)

IP range PromptProd Share [%] FrontierProd Share [%]
128.*.*.* 77.92 91.25
188.*.*.* 21.79 7.97
137.*.*.* 0.28 0.78 0.01 0.00

Info It is interesting to note that for the PromptProd queries, a significant share of them were issued from Wigner (IP 188.*), whereas most of the FrontierProd queries where from Meyrin (the other IP ranges)

Situation under normal load: Early Evening

In writing -- LuisLinares - 08 Aug 2014

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Topic revision: r4 - 2014-08-08 - LuisLinares
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