Atlas Canada Lightpath

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Atlas Canada Lightpath Data Transfer Trial
Corrie Kost, Steve McDonald (TRIUMF) Bryan Caron
(UofAlberta), Wade Hong (Carleton)
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Brownie 2.5 TeraByte RAID array

• 16 x 160 GB IDE disks (5400 rpm 2MB cache)
• hot swap capable
• Dual ultra160 SCSI interface to host
• Maximum transfer 65 MB/sec
• Triple hot swap power supplies
• CAN 15k
• Arrives July 8th 2002

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What to Do while waiting for server to arrive

• IBM PRO6850 Intellistation (Loan)
• Dual 2.2 GHz Xeons
• 2 PCI 64bit/66MHz
• 4 PCI 33bit/33MHz
• 1.5 GB RAMBUS
• Add 2 Promise Ultra100
• IDE controllers and 5 Disks
• Each disk on its own IDE controller for maximum
  IO
• Begin Linux Software RAID performance tests
  170/130 MB/sec Read/Write

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The Long Road to High Disk IO

• IBM cluster x330s RH7.2 disk io 15 MB/sec
  (slow??)
• expect 45 MB/sec for any modern single drive
• Need 2.4.18 Linux kernel to support gt1TB
  filesystems
• IBM cluster x330s RH7.3 disk io 3 MB/sec
• What is going on
• Red Hat modified serverworks driver broke DMA on
  x330s
• x330s ATA 100 drive, BUT controller is only
  UDMA 33
• Promise controllers capable of UDMA 100 but need
  latest kernel patches for 2.4.18 before drives
  recognise UDMA100
• Finally drives/controller both working at
  UDMA100 45MB/sec
• Linux software raid0 2 drives 90MB/sec, 3
  drives 125 MB/sec
• 4 drives 155MB/sec, 5 drives 175 MB/sec
• Now we are ready to start network transfers

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So what are we going to do?
did we
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• Demonstrate a manually provisioned e2e
  lightpath
• Transfer 1TB of ATLAS MC data generated in Canada
  from TRIUMF to CERN
• Test out 10GbE technology and channel bonding
• Establish a new benchmark for high performance
  disk to disk throughput over a large distance

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Comparative Results(TRIUMF to CERN)
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What is an e2e Lightpath

• Core design principle of CAnet 4
• Ultimately to give control of lightpath
  creation, teardown and routing to the end
  user
• Hence, Customer Empowered Networks
• Provides a flexible infrastructure for emerging
  grid applications

• Alas, can only do things manually today

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CAnet 4 Layer 1 Topology
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The Chicago Loopback

• Need to test TCP/IP and Tsunami protocols over
  long distances, arrange optical loop via
  StarLight
• ( TRIUMF-BCNET-Chicago-BCNET-TRIUMF )
• 91ms RTT
• TRIUMF - CERN RRT 200ms Told Damir, we really
  needed to have a double loopback
• No problem
• The loopback2 was setup a few days later
  (RTT193ms)
• (TRIUMF-BCNET-Chicago-BCNET-Chicago-BCNET-TRIUMF)

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TRIUMF Server SuperMicro P4DL6 (Dual Xeon
2GHz) 400 MHz front side bus 1 GB DDR2100
RAM Dual Channel Ultra 160 onboard
SCSI SysKonnect 9843 SX GbE 2 independent PCI
buses 6 PCI-X 64 bit/133 Mhz capable 3ware 7850
RAID controller 2 Promise Ultra 100 Tx2
controllers
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CERN Server SuperMicro P4DL6 (Dual Xeon 2GHz) 400
MHz front side bus 1 GB DDR2100 RAM Dual Channel
Ultra 160 onboard SCSI SysKonnect 9843 SX GbE 2
independent PCI buses 6 PCI-X 64 bit/133 Mhz
capable 2 3ware 7850 RAID controller
6 IDE drives on each 3-ware controllers RH7.3 on
13th drive connected to on-board IDE WD Caviar
120GB drives with 8Mbyte cache
RMC4D from HARDDATA
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TRIUMF Backup Server SuperMicro P4DL6 (Dual Xeon
1.8GHz) Supermicro 742I-420 17 4U Chassis 420W
Power Supply 400 MHz front side bus 1 GB
DDR2100 RAM Dual Channel Ultra 160 onboard
SCSI SysKonnect 9843 SX GbE 2 independent PCI
buses 6 PCI-X 64bit/133 MHz capable 2 Promise
Ultra 133 TX2 controllers 1 Promise Ultra
100 TX2 controller
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Back-to-back tests over 12,000km loopback using
designated servers
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Operating System

• Redhat 7.3 based Linux kernel 2.4.18-3
• Needed to support filesystems gt 1TB
• Upgrades and patches
• Patched to 2.4.18-10
• Intel Pro 10GbE Linux driver (early stable)
• SysKonnect 9843 SX Linux driver (latest)
• Ported Sylvain Ravots tcp tune patches

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Intel 10GbE Cards

• Intel kindly loaned us 2 of their Pro/10GbE LR
  server adapters cards despite the end of their
  Alpha program
• based on Intel 82597EX 10 Gigabit Ethernet
  Controller
• Note length of card!

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Extreme Networks
TRIUMF
CERN
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EXTREME NETWORK HARDWARE
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IDE Disk Arrays
CERN Receive Host
TRIUMF Send Host
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Disk Read/Write Performance

• TRIUMF send host
• 1 3ware 7850 and 2 Promise Ultra 100TX2 PCI
  controllers
• 12 WD 7200 rpm UDMA 100 120 GB hard drives (1.4
  TB)
• Tuned for optimal read performance (227/174 MB/s)
• CERN receive host
• 2 3ware 7850 64-bit/33 MHz PCI IDE controllers
• 12 WD 7200 rpm UDMA 100 120 GB hard drives (1.4
  TB)
• Tuned for optimal write performance (295/210 MB/s)

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THUNDER RAID DETAILS
raidstop /dev/mdo mkraid R /dev/md0 mkfs -t
ext3 /dev/md0 mount -t ext2 /dev/mdo /raid0
/root/raidtab raiddev /dev/md0
raid-level 0 nr-raid-disks 12
persistent-superblock 1 chunk-size
512 ?kbytes device /dev/sdc
raid-disk 0 device
/dev/sdd raid-disk 1 device
/dev/sde raid-disk 2
device /dev/sdf raid-disk
3 device /dev/sdg
raid-disk 4 device
/dev/sdh raid-disk 5 device
/dev/sdi raid-disk 6
device /dev/sdj raid-disk
7 device /dev/hde
raid-disk 8 device
/dev/hdg raid-disk 9 device
/dev/hdi raid-disk 10
device /dev/hdk raid-disk
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8 drives on 3-ware
4 drives on 2 Promise
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Black Magic

• We are novices in the art of optimizing system
  performance
• It is also time consuming
• We followed most conventional wisdom, much of
  which we dont yet fully understand

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Testing Methodologies

• Began testing with a variety of bandwidth
  characterization tools
• pipechar, pchar, ttcp, iperf, netpipe, pathcar,
  etc
• Evaluated high performance file transfer
  applications
• bbftp, bbcp, tsunami, pftp
• Developed scripts to automate and to scan
  parameter space for a number of the tools

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Disk I/O Black Magic

• min max read ahead on both systems
• sysctl -w vm.min-readahead127
• sysctl -w vm.max-readahead256
• bdflush on receive host
• sysctl -w vm.bdflush2 500 0 0 500 1000 60 20
  0
• or
• echo 2 500 0 0 500 1000 60 20 0
  gt/proc/sys/vm/bdflush
• bdflush on send host
• sysctl -w vm.bdflush30 500 0 0 500 3000 60 20
  0
• or
• echo 30 500 0 0 500 3000 60 20 0
  gt/proc/sys/vm/bdflush

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Misc. Tuning and other tips
/sbin/elvtune r 512 /dev/sdc (same for other
11 disks) /sbin/elvtune w 1024 /dev/sdc (same
for other 11 disks) -r sets the max latency
that the I/O scheduler will provide on each
read -w sets the max latency that the I/O
scheduler will provide on each write
When the /raid disk refuses to dismount! Works
for kernels 2.4.11 or later. umount -l /raid
(then mount umount)
lazy
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Disk I/O Black Magic

• Disk I/O elevators (minimal impact noticed)
• /sbin/elvtune
• Allows some control of latency vs throughput
• Read_latency set to 512 (default 8192)
• Write_latency set to 1024 (default 16384)
• atime
• Disables updating the last time a file has been
  accessed (typically for file servers)
• mount t ext2 o noatime /dev/md0 /raid
• Typically, ext3 writes?90Mbytes/sec while for
  ext2 writes 190Mbytes/sec
• Reads minimally affected. We always used ext2

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Disk I/O Black Magic

• IRQ Affinity
• root_at_thunder root more /proc/interrupts
• CPU0 CPU1
• 0 15723114 0 IO-APIC-edge timer
• 1 12 0 IO-APIC-edge
  keyboard
• 2 0 0 XT-PIC
  cascade
• 8 1 0 IO-APIC-edge rtc
• 10 0 0 IO-APIC-level
  usb-ohci
• 14 22 0 IO-APIC-edge ide0
• 15 227234 2 IO-APIC-edge ide1
• 16 126 0 IO-APIC-level
  aic7xxx
• 17 16 0 IO-APIC-level
  aic7xxx
• 18 91 0 IO-APIC-level ide4,
  ide5, 3ware Storage Controller
• 20 14 0 IO-APIC-level ide2,
  ide3
• 22 2296662 0 IO-APIC-level
  SysKonnect SK-98xx
• 24 2 0 IO-APIC-level eth3
• 26 2296673 0 IO-APIC-level
  SysKonnect SK-98xx
• 30 26640812 0 IO-APIC-level eth0
• NMI 0 0

Need to have PROCESS Affinity - but this requires
2.5 kernel
echo 1 gt/proc/irq/18/smp_affinity
? use CPU0 echo 2 gt/proc/irq/18/smp_affinity
? use CPU1 echo 3
gt/proc/irq/18/smp_affinity
? use either cat /proc/irq/prof_cpu_mask
gt/proc/irq/18/smp_affinity ? reset to default
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TCP Black Magic

• Typically suggested TCP and net buffer tuning
• sysctl -w net.ipv4.tcp_rmem"4096 4194304
  4194304"
• sysctl -w net.ipv4.tcp_wmem"4096 4194304
  4194304"
• sysctl -w net.ipv4.tcp_mem"4194304 4194304
  4194304"
• sysctl -w net.core.rmem_default65535
• sysctl -w net.core.rmem_max8388608
• sysctl -w net.core.wmem_default65535
• sysctl -w net.core.wmem_max8388608

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TCP Black Magic

• Sylvain Ravots tcp tune patch parameters
• sysctl -w net.ipv4.tcp_tune115 115 0
• Linux 2.4 retentive TCP
• Caches TCP control information for a destination
  for 10 mins
• To avoid caching
• sysctl -w net.ipv4.route.flush1

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We are live continent to continent!

• e2e lightpath up and running Friday Sept 20 2145
  CET

traceroute to cern-10g (192.168.2.2), 30 hops
max, 38 byte packets 1 cern-10g (192.168.2.2)
161.780 ms 161.760 ms 161.754 ms
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BBFTP Transfer

• Vancouver ONS
• ons-van01(enet_15/1)
• Vancouver ONS
• ons-van01(enet_15/2)

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BBFTP Transfer

• Chicago ONS
• GigE Port 1
• Chicago ONS
• GigE Port 2

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Tsunami Transfer

• Vancouver ONS
• ons-van01(enet_15/1)
• Vancouver ONS
• ons-van01(enet_15/2)

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Tsunami Transfer

• Chicago ONS
• GigE Port 1
• Chicago ONS
• GigE Port 2

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Sunday Nite Summaries
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Exceeding 1Gbit/sec ( using tsunami)
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What does it mean for TRIUMFin the long TERM

• Established a relationship with a grid of
  people for future networking projects
• Upgraded WAN connection from 100Mbit to
• 4 x 1GB Ethernet connections directly to BCNET
• Canarie educational/research network
• Westgrid GRID computing
• Commercial Internet
• Spare (research development)
• Recognition that TRIUMF has the expertise and the
  Network connectivity for large scale and high
  speed data transfers necessary for upcoming
  scientific programs, ATLAS, WESTGRID, etc

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Lessons Learned 1

• Linux software RAID faster than most conventional
  SCSI and IDE hardware RAID based systems.
• One controller for each drive, more disk spindles
  the better
• More than 2 Promises / machine possible
  (100/133Mhz)
• Unless programs are multi-threaded or kernel
  permits process locking, Dual CPU will not give
  best performance.
• Single 2.8 GHz is likely to outperform Dual 2.0
  GHz, for a single purpose machine like our
  fileservers.
• More memory the better

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Misc. comments

• No hardware failure even for the 50 disks!
• Largest file transferred 114 Gbytes (Sep 24)
• Tar, compressing, etc take longer than transfer
• Deleting files can take a lot of time
• Low cost of project - 20,000 with most of that
  recycled

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?220Mbytes/sec
175Mbytes/sec
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Acknowledgements

• Canarie
• Bill St. Arnaud, Rene Hatem, Damir Pobric, Thomas
  Tam, Jun Jian
• Atlas Canada
• Mike Vetterli, Randall Sobie, Jim Pinfold, Pekka
  Sinervo, Gerald Oakham, Bob Orr, Michel Lefebrve,
  Richard Keeler
• HEPnet Canada
• Dean Karlen
• TRIUMF
• Renee Poutissou, Konstantin Olchanski,
  Mike Vetterli (SFU /
  Westgrid),
• BCNET
• Mike Hrybyk, Marilyn Hay, Dennis OReilly, Don
  McWilliams

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Acknowledgements

• Extreme Networks
• Amyn Pirmohamed, Steven Flowers, John Casselman,
  Darrell Clarke, Rob Bazinet, Damaris Soellner
• Intel Corporation
• Hugues Morin, Caroline Larson, Peter Molnar,
  Harrison Li, Layne Flake, Jesse Brandeburg

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Acknowledgements

• Indiana University
• Mark Meiss, Stephen Wallace
• Caltech
• Sylvain Ravot, Harvey Neuman
• CERN
• Olivier Martin, Paolo Moroni, Martin Fluckiger,
  Stanley Cannon, J.P Martin-Flatin
• SURFnet/Universiteit van Amsterdam
• Pieter de Boer, Dennis Paus, Erik.Radius,
  Erik-Jan.Bos, Leon Gommans, Bert Andree, Cees de
  Laat

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Acknowledgements

• Yotta Yotta
• Geoff Hayward, Reg Joseph, Ying Xie, E. Siu
• BCIT
• Bill Rutherford
• Jalaam
• Loki Jorgensen
• Netera
• Gary Finley

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ATLAS Canada
Alberta
SFU
Montreal
Victoria
UBC
Carleton
York
TRIUMF
Toronto
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LHC Data Grid Hierarchy
CERN/Outside Resource Ratio 12Tier0/(?
Tier1)/(? Tier2) 111
PByte/sec
100-400 MBytes/sec
Online System
Experiment
CERN 700k SI95 1 PB Disk Tape Robot
Tier 0 1
HPSS
2.5 Gbps
Tier 1
FNAL 200k SI95 600 TB
IN2P3 Center
INFN Center
RAL Center
2.5 Gbps
Tier 2
2.5 Gbps
Tier 3
Institute 0.25TIPS
Institute
Institute
Institute
Physicists work on analysis channels Each
institute has 10 physicists working on one or
more channels
0.11 Gbps
Physics data cache
Tier 4
Workstations
Slide courtesy H. Newman (Caltech)
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The ATLAS Experiment
Canada
Canada