I've run a number of tests on the Paris servers (following from complaints from a British ISP complaining of slower access times from Paris than from Florida). They show that: * We have no connectivity/bandwidth problems (we shoot up to 100 megabits/s to major French ISPs, which is the limitation brought by our Ethernet uplink; not so long ago the same was true of the Florida cluster). * Under light loads, the machines give pages 3x faster than the Florida cluster (.24s vs .67s; that's to be expected, there's a 100ms RTT to Florida that cannot be avoided, for instance) * The machines are WAY TOO SLOW under heavy load. They are Celeron 600s, slower than my old laptop!
So essentially, there's no problem with the hosting and networking. It's just that the machines don't follow the load.
-- DM
Tests under light load:
* PARIS SERVERS / 20 SIMULTANEOUS CLIENTS $ siege -c 20 http://fr.wikipedia.org/wiki/Accueil ** siege 2.62 ** Preparing 20 concurrent users for battle. The server is now under siege... Lifting the server siege... done. Transactions: 638 hits Availability: 100.00 % Elapsed time: 23.52 secs Data transferred: 37.13 MB Response time: 0.24 secs Transaction rate: 27.13 trans/sec Throughput: 1.58 MB/sec Concurrency: 6.50 Successful transactions: 638 Failed transactions: 0 Longest transaction: 3.20 Shortest transaction: 0.07
* FLORIDA SERVERS / 20 SIMULTANEOUS CLIENTS $ siege -c 20 http://de.wikipedia.org/wiki/Hauptseite ** siege 2.62 ** Preparing 20 concurrent users for battle. The server is now under siege... Lifting the server siege... done. Transactions: 918 hits Availability: 100.00 % Elapsed time: 54.11 secs Data transferred: 28.94 MB Response time: 0.67 secs Transaction rate: 16.97 trans/sec Throughput: 0.53 MB/sec Concurrency: 11.29 Successful transactions: 918 Failed transactions: 0 Longest transaction: 3.68 Shortest transaction: 0.57
So it's 3x faster to fetch a page from a not much loaded Paris cluster than from Florida, which is probably nice for French users.
Tests under higher load: * PARIS SERVERS [chloe] / 100 SIMULTANEOUS CLIENTS $ siege -c 100 http://fr.wikipedia.org/wiki/Accueil ** siege 2.62 ** Preparing 100 concurrent users for battle. The server is now under siege... Lifting the server siege... done. Transactions: 6163 hits Availability: 100.00 % Elapsed time: 87.62 secs Data transferred: 360.31 MB Response time: 0.90 secs Transaction rate: 70.34 trans/sec Throughput: 4.11 MB/sec Concurrency: 63.09 Successful transactions: 6163 Failed transactions: 0 Longest transaction: 9.80 Shortest transaction: 0.12
Note the sharp increase in response time. CPU is 80-95% on chloe under such tests.
$ siege -c 200 http://fr.wikipedia.org/wiki/Accueil ** siege 2.62 ** Preparing 200 concurrent users for battle. The server is now under siege... Lifting the server siege... done. Transactions: 5257 hits Availability: 100.00 % Elapsed time: 60.64 secs Data transferred: 307.35 MB Response time: 1.74 secs Transaction rate: 86.69 trans/sec Throughput: 5.07 MB/sec Concurrency: 150.46 Successful transactions: 5257 Failed transactions: 0 Longest transaction: 34.87 Shortest transaction: 0.24
* FLORIDA [www11], HIGH LOAD $ siege -c 200 http://de.wikipedia.org/wiki/Hauptseite ** siege 2.62 ** Preparing 200 concurrent users for battle. The server is now under siege... Lifting the server siege... done. Transactions: 7111 hits Availability: 100.00 % Elapsed time: 47.08 secs Data transferred: 222.15 MB Response time: 0.81 secs Transaction rate: 151.04 trans/sec Throughput: 4.72 MB/sec Concurrency: 122.22 Successful transactions: 7111 Failed transactions: 0 Longest transaction: 10.71 Shortest transaction: 0.57
* FLORIDA, EVEN HIGHER LOAD $ siege -c 500 http://de.wikipedia.org/wiki/Hauptseite ** siege 2.62 ** Preparing 500 concurrent users for battle. The server is now under siege... Lifting the server siege... done. Transactions: 12160 hits Availability: 100.00 % Elapsed time: 45.41 secs Data transferred: 379.88 MB Response time: 1.33 secs Transaction rate: 267.78 trans/sec Throughput: 8.37 MB/sec Concurrency: 354.86 Successful transactions: 12160 Failed transactions: 0 Longest transaction: 15.02 Shortest transaction: 0.68
* FLORIDA, EVEN HIGHER LOAD $ siege -c 600 http://de.wikipedia.org/wiki/Hauptseite ** siege 2.62 ** Preparing 600 concurrent users for battle. The server is now under siege... Lifting the server siege... done. Transactions: 9504 hits Availability: 100.00 % Elapsed time: 38.13 secs Data transferred: 296.91 MB Response time: 1.79 secs Transaction rate: 249.25 trans/sec Throughput: 7.79 MB/sec Concurrency: 445.22 Successful transactions: 9504 Failed transactions: 0 Longest transaction: 15.89 Shortest transaction: 0.71
wikitech-l@lists.wikimedia.org