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A Case for an Open Source Data Repository. Archana Ganapathi Department of EECS, UC Berkeley (archanag@cs.berkeley.edu). Why do we study failure data?. Understand cause->effect relationship between configurations and system behavior

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A case for an open source data repository

A Case for an Open Source Data Repository

Archana Ganapathi

Department of EECS, UC Berkeley

(archanag@cs.berkeley.edu)


Why do we study failure data
Why do we study failure data?

  • Understand cause->effect relationship between configurations and system behavior

  • Still don’t have a complete understanding of failures in systems

    • Can’t worry about fixing problems if we don’t understand them in the first place

  • Gauge behavioral changes over time

  • Need realistic workload/faultload data to test/evaluate systems

  • Success stories…people have benefited from failure data analysis


Crash data collection success stories
Crash data collection success stories

  • Berkeley EECS

  • BOINC

  • 2 Unnamed Companies



Definitions
Definitions

  • Crash

    • Event caused by a problem in the operating system(OS) or application(app)

    • Requires OS or app restart.

  • Application Crash

    • A crash occurring at user-level, caused by one or more components (.exe/.dll files)

    • Requires an application restart.

  • Application Hang

    • An application crash caused as a result of the user terminating a process that is potentially deadlocked or running an infinite loop.

    • Component (.exe/.dll file routing) causing the loop/deadlock cannot be identified (yet)

  • OS Crash

    • A crash occurring at kernel-level, caused by memory corruption, bad drivers or faulty system-level routines.

    • Blue-screen-generating crashes require a machine reboot

    • Windows explorer crashes require restarting the explorer process.

  • Bluescreen

    • An OS crash that produces a user-visible blue screen followed by a non-optional machine reboot.


Procedure
Procedure

  • Collect crash dumps from two different sources

    • UC Berkeley EECS department

    • BOINC volunteers

  • Filter data/form crash clusters to avoid double-counting

    • Account for shared resources, dependent processes, system instability, user retry

  • Parse/Interpret crash dumps using Debugging tools for Windows

  • Study both application crash behavior and operating systems crashes

    • Supplement crash data with usage data




Usage crashes per day of week
Usage/Crashes per day of week

  • EECS department users use their EECS computers Monday through Friday.

  • Few users use computers on weekends.

  • Crashes do not occur uniformly across the five days of the working week.


Usage crashes per hour of day
Usage/Crashes per hour of day

  • Most people work during the typical hours of 9am to 5pm.

  • Our data set involves users of various affiliations to the department, hence the wider spectrum of work schedules



Automatic clustering experiment for categorizing apps
Automatic Clustering Experiment for Categorizing Apps

  • Augment the crash data with information about usage patterns and program dependencies

  • Feed data into the k-means and agglomerative clustering algorithms to determine which applications are behaviorally related.

  • We determined that we did not have enough data to derive a method to categorize applications in our data set

    • Need several instances of every (application, component, error code) combo

  • As a last resort, we chose to categorize apps based on categorization based on application functionality






Boinc http winerror cs berkeley edu crashcollection
BOINC http://winerror.cs.berkeley.edu/crashcollection/

  • Berkeley Open Infrastructure for Network Computing

  • Users download boinc client app

  • Crash dumps are scraped/sent to boinc servers

  • Currently 791 accounts created for crash collection + resource management

    • 492 users for crash collection


Os crashes
OS Crashes

  • Driver faults

    • asynchronous events

    • code must follow kernel programming etiquette

    • exceedingly difficult to debug

  • Memory corruption

    • Hardware problems (e.g. non-ECC mem)

    • Software-related

    • 47 of these in our dataset so far…don’t have tools to analyze these in detail




Summary of crash analysis
Summary of crash analysis crashes)

  • Application crashes are caused by both faulty non-robust dll files as well as impatient users

  • OS crashes are predominantly caused by poorly-written device driver code

  • Commonly used core components are blamed for most crashes

    • need to improve reliability of these components


Practical techniques to reduce crashes
Practical techniques to reduce crashes crashes)

  • Software-Based Fault Isolation

  • Nooks

  • Separate protection level for drivers

  • Move driver code to user libraries

  • Virtual Machine for each unsafe/distrusted app


Lessons from crash data study
Lessons from crash data study crashes)

  • Clearly people want to know what’s wrong and how to fix it

  • The more feedback we give, the more data sets we receive

  • ...but it’s not as easy as it sounds


What kinds of data should we collect
What kinds of data should we collect? crashes)

  • Failure data

  • Configuration information

  • Logs of normal behavior

  • Usage data

  • Performance logs

  • Annotations of data

  • Collect data for Individual Machines + Services


Why are people afraid of sharing data
Why are people afraid of sharing data? crashes)

  • Fear of public humiliation (reverse engineering what user was doing)

  • Revealing problems within their organization

  • Fear of competitors using data against them

  • Revealing loopholes through which malware can easily propagate.

  • Revealing dependability problems in third party products (MS)


Non technical challenges to getting data
Non-technical challenges to getting data crashes)

  • Collecting (useful) data is tedious

    • What information is “necessary and sufficient” to understand data trends?

  • Privacy concerns

    • Especially with usage data

  • Finding the person with access to data

    • No central location that can be queried for data

  • Legal agreements take a long time to draft

    • Researchers are more willing to share data than lawyers

  • Publicity


Technical solution
Technical solution crashes)

  • Amortize the cost of data collection by building an open source repository

  • Provide a set of tools to cleanse and mine the data


What tools should we implement
What tools should we implement? crashes)

  • Collect

    • BOINC

    • Instrumentation (MS, Pinpoint)

    • Pre-aggregated data from companies

  • Anonymize/Preprocess

    • Pre-written anonymization tools

    • Company-specific privacy requirements

      • Hash values of certain fields

      • Drop irrelevent fields

      • Mask part of data


Tools cont d
Tools cont’d crashes)

  • Store

    • Open-source repository schema

    • Common log format/ data descriptor headers

    • Tools to convert log metadata to common format to cross-link data tables

    • Sample queries: data mining ~ asking questions about data as it is

  • Analyze/Experiment

    • SLT algorithms

    • Visualization

    • Stream processing

    • Other tools (eg. WinDbg)


Thoughts on collection anonymization
Thoughts on Collection/Anonymization crashes)

  • Defining necessary and sufficient

    • Bad example: Cannot correlate crashes if we getting rid of all user/machine names

    • Good example: Hash user/machine names

  • Default: hide if not necessary?

  • What would it take for you not to invoke the legal dept?


Thoughts on storage analysis
Thoughts on Storage/Analysis crashes)

  • Use time/data source as primary key?

  • How domain-specific should the common format be?

  • Management logistics…

  • Access control…


Acronym suggestions
Acronym Suggestions??? crashes)

Open Source (Failure) Data Repository