Ed – Lanc UKLight
Overview
 Alternate Protocol Work
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Outline of Objectives
Hardware
Disk Testing
Basic Network Testing
File Transfer Testing
Further Work
 Network Utilisation Monitoring
Outline Objectives
 Investigate the use of an alternate (in this
case UDT) protocol to maximise the
potential of an optical circuit
 Utilise this protocol in such a was as to be
of practicable use to users of the grid.
Hardware
 Servers :
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Dual Xeon 3.2GHz dual core
2 GB RAM
Dual PCI-X bus
2 x Gigabit Ethernet
LSI Megaraid 300x8 SATA II Raid controller
6 x 74GB 8MB cache WD Raptor SATA disks
1 x 80GB 8MB cache WD SATA system disk
Disk Testing
 Tested using bonnie++ using 4.5 times the
physical RAM for the file size to avoid
caching in RAM.
 Multiple Configurations
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Raid 0 with write caching enabled
Raid 0 with write caching disabled
Raid 5 with write caching enabled
Raid 5 with write caching disabled
System Disk
Disk Testing Results
Ext3 Write
Speed / CPU
Load
Ext3 Read
Speed / CPU
Load
XFS Write
Speed / CPU
Load
XFS Read
Speed / CPU
Load
System Disk
320 Mb/s
(20%)
336 MB/s
(10%)
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Raid 0 (write
caching
disabled)
1544 Mb/s
(96%)
1304 MB/s
(33%)
2160 Mb/s
(63%)
1304 Mb/s
(34%)
Raid 0 (write
caching
enabled)
1143 Mb/s
(70%)
1221 Mb/s
(30%)
1184 Mb/s
(33%)
1124 Mb/s
(28%)
Raid 5 (write
caching
disabled)
90 Mb/s
(6%)
363 Mb/s
(10%)
97 Mb/s
(3%)
348 Mb/s
(10%)
Raid 5 (write
caching
enabled)
905 Mb/s
(60%)
1222 Mb/s
(30%)
1001 Mb/s
(30%)
1216 Mb/s
(30%)
Basic Network Testing
 Tested using :
 iperf – for both TCP and UDP
 UDT “iperf like” test application
 Tests were performed with default kernel
settings and then after “tuning”
 BDP for this link should be :
 BDP = Bandwidth (MB/s) * RTT (seconds)
 BDP = (1 * 1024 / 8) * (0.3 / 1000)
 BDP = 0.0384 MB (39.32KB)
Basic Network Test results
Protocol
Throughput Before
Tuning
Throughput After
Tuning
TCP
650 Mb/s *
940 Mb/s
UDP
957 Mb/s
957 Mb/s
UDT
950 Mb/s
950 Mb/s
* Default window sizes for iperf are :
• Server : 85.3 KB
• Client : 16 KB
It was possible to achieve higher rates by requesting a larger window
size on the server (940 Mb/s can be achieved with a window size of
150KB)
File Transfer Tests
 Tested using :
 ftp
 GridFTP
 UDT file copy test application
 Again tests were carried out before and
after kernel tuning
File Transfer Test Results
Transfer
Program
Throughput Before
Tuning
Throughput After
Tuning
ftp
565 Mb/s
820 Mb/s
GridFTP
570 Mb/s
850 Mb/s
UDT test
application
460 Mb/s
935 Mb/s
Further Work
 The Basic Network tests and the File
transfer tests need to be re-performed
once the UKLight link between Lancaster
and Edinburgh is fully functional
 Integration of UDT into a functional
GridFTP server and client
Network Utilisation Monitoring
 Currently have 2 method of viewing utilisation
 “Weathermap” webpage
 Gridportal real time monitor
 Raw data is currently collected using MRTG
 Future work
 Moving away from MRTG to rrd to reduce the time
between measurements
 Publishing results using a web service (perfsonar)
 Adding functionality to allow the monitoring of file
transfers.