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To the Terabyte and Beyond! Leveraging Pilot and Wireshark to Analyze Truly Massive Packet Traces June 17, 2010 Loris Degioanni CTO | CACE Technologies SHARK FEST ‘10 Stanford University June 14-17, 2010. Packet Aquisition. Capture Card. Dedicated card is essential
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To the Terabyte and Beyond! Leveraging Pilot and Wireshark to Analyze Truly Massive Packet Traces June 17, 2010 Loris Degioanni CTO | CACE Technologies SHARKFEST‘10 Stanford University June 14-17, 2010
Capture Card • Dedicated card is essential • No network stack overhead • Minimizes copies • Optimizes locality • Filtering capability in the card normally not really useful • Unless in some unusual conditions, the application wants to see everything • PCI bus is the only resource that card filtering optimizes • Any tap nowadays can do basic filtering • Small packets is the worst condition • CACE Turbocap • Hybrid between home-built and off the shelf • No unnecessary features (who needs filtering?) • Affordable price
CPU • Bottlenecks • CPU clock (expensive) • Number of CPUS (cheap) • Multi-threading hard to leverage when capturing and processing network packets • Network monitoring is intrinsically sequential • Locking is evil • Doing things more than once is better than locking • At 10Gbps, cache coherency is a big deal • Small packets is the worst condition
Disk • Bottlenecks • Single disk write speed • Number of spindles • Raid Controller • Big packets is the worst condition • Solid State? Not a good idea yet • Single disk performance is not really the bottleneck • Cost is an important factor when you build a system with tens of disks • Reliability not as proven as the old magnetic disks
I can capture a lot of packets. Now what? • Read of packets must be non-disruptive! • Even if I stop the capture process, since I was writing at full speed, reading the data is going to take around the same time of writing it • Read needs to be localized • I need high level visibility to reach the point I need Indexing
Standalone card vs. kit A network card nowadays is not enough to build a functional packet capture system.
Indexing • While capturing, on a Shark Appliance capture job • On a trace file, after the fact • Summary of the network traffic • Volume, talkers and protocol information • Coordinated with the packet store • “Netflow on steroids” • Designed to be extremely efficient in terms of disk usage • Coordinated with the packet store
Indexing Index file Time intervals Index entry Time index File Positions pcap file Packet