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Configurable Security for Scavenged Storage Systems. Abdullah Gharaibeh with: Samer Al-Kiswany, Matei Ripeanu . NetSysLab The University of British Columbia. Introduction. Data Deluge Scientific applications (e.g., climate simulation, biological research) - PowerPoint PPT Presentation
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Configurable Security for Scavenged Storage Systems
NetSysLabThe University of British Columbia
Abdullah Gharaibeh
with: Samer Al-Kiswany, Matei Ripeanu
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Introduction
StorageSS ‘08
Data Deluge
Scientific applications (e.g., climate simulation, biological research)
Checkpointing (e.g., application and virtual machine checkpointing)
Scavenged storage provides a solution with good price/performance ratio
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Scavenged Storage?
Systems that opportunistically aggregate idle disk space and I/O bandwidth from participating workstations.
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Offers two main advantages:
high-throughput due to striping and component decoupling
low-cost solution as it is built atop of commodity resources
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Trust Assumptions in Distributed Storage Systems
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Completely trusted environment All system components and communication channels are trusted Hosted on dedicated clusters and are optimized for performance E.g., GoogleFS, Lustre
Untrusted environment System components and communication channels are untrusted Deployed over wide area networks E.g., Farsite, OceanStore
Partially trusted environment Includes a combination of trusted and untrusted components E.g., Plutus, MosaStore
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Our Goal
We aim to design and implement a security protocol in the context of a partially trusted environment, and to evaluate the associated overheads for different security levels.
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Our Environment
A partially trusted environment Trusted metadata service Untrusted storage nodes, clients and communication channels
An adversary can Modify and deploy a malicious client or storage node Spoof messages on communication channels
The system doesn’t need to provide stored data confidentiality As a tradeoff to simplicity and performance
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We conduct this study in the context of MosaStore scavenged storage system
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Outline
MosaStore Architecture
Security Requirements
Security Protocol
Evaluation
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MosaStore Architecture
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MosaStore Design Guidelines
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Component decoupling – to improve scalability
Lazy interaction – to enable high-performance
Statelessness – to minimize failure effects and recovery overhead
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Outline
MosaStore Architecture
Security Requirements
Security Protocol
Evaluation
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Requirements
Requirements related to security services
Authentication and authorization
Data and transport integrity
Accountability (i.e. assigning blame for integrity violations and data loss)
Requirements related to system characteristics
Acceptable performance degradation
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Security Protocol – Supporting mechanisms
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Public key cryptography
Used to manage trust and certification
Two types of certificates Machine certificates User certificate
Generic Security Services API (GSSAPI) Used to establish mutual authentication and security contexts
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Security protocol – write operation
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Outline
MosaStore Architecture
Security Requirements
Security Protocol
Evaluation
StorageSS ‘08
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Protocol Evaluation – Security Argument
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Authentication: offered by enforcing mutual authentication between communicating entities
Authorization: provided by an independent access control module consulted by the manager
Transport integrity: provided by sending all traffic within the security context resulted from the mutual authentication
Stored data integrity: maintained by having the manager to store per chunk hash
Accountability (i.e. responsibility for integrity violations): proved by using chunk receipts stored at the manager and having the client to sign each stored chunk
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Performance Evaluation
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Testbed:10 machinesEach machine has : Quad-core 2.33GHz Xeon processors, 4 GB RAM, connected at 1Gbps.
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Performance Evaluation
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1GB file split into 1MB chunks, one client and eight benefactors
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Performance Evaluation
StorageSS ‘08
1GB file split into 1MB chunks, one client and eight benefactors
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Performance Evaluation
StorageSS ‘08
1GB file split into 1MB chunks, one client and eight benefactors
Caching dramatically improves performanceLess than 17% degradation for the full solution
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File Size Impact
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Files are split into 1MB chunks, one client and eight benefactors
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Number of Benefactors Impact
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1 GB file split into 1MB chunks, one client
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Summary
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Design and implementation of a security protocol that operates in a partially trusted environment (only the management service is trusted)
Protocol evaluation demonstrates
Low performance degradation in small deployments
Close to original performance in deployments that offer more parallelism
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Thank you
netsyslab.ece.ubc.ca
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Security Protocol – Write Operation
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GSS-API
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Replication
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The manager sends a signed replicate command (contains the source benefactor B and its chunk receipt) to benefactor A the target for the new chunk replica.
Benefactor A copies the data from benefactor B and verify it against the chunk receipt
Benefactor A generates a chunk receipt and sends it back to the manager.
