The design and implementation of a log-structured file system
ACM Transactions on Computer Systems (TOCS)
Logical vs. physical file system backup
OSDI '99 Proceedings of the third symposium on Operating systems design and implementation
Exploiting Gray-Box Knowledge of Buffer-Cache Management
ATEC '02 Proceedings of the General Track of the annual conference on USENIX Annual Technical Conference
Virtualizing I/O Devices on VMware Workstation's Hosted Virtual Machine Monitor
Proceedings of the General Track: 2002 USENIX Annual Technical Conference
LOGICAL DISK: A SIMPLE NEW APPROACH TO IMPROVING FILE SYSTEM PERFORMANCE
LOGICAL DISK: A SIMPLE NEW APPROACH TO IMPROVING FILE SYSTEM PERFORMANCE
Xen and the art of virtualization
SOSP '03 Proceedings of the nineteenth ACM symposium on Operating systems principles
Semantically-Smart Disk Systems
FAST '03 Proceedings of the 2nd USENIX Conference on File and Storage Technologies
Data lifetime is a systems problem
Proceedings of the 11th workshop on ACM SIGOPS European workshop
Second-tier cache management using write hints
FAST'05 Proceedings of the 4th conference on USENIX Conference on File and Storage Technologies - Volume 4
Live migration of virtual machines
NSDI'05 Proceedings of the 2nd conference on Symposium on Networked Systems Design & Implementation - Volume 2
Self-securing storage: protecting data in compromised system
OSDI'00 Proceedings of the 4th conference on Symposium on Operating System Design & Implementation - Volume 4
Trading capacity for performance in a disk array
OSDI'00 Proceedings of the 4th conference on Symposium on Operating System Design & Implementation - Volume 4
OSDI'04 Proceedings of the 6th conference on Symposium on Opearting Systems Design & Implementation - Volume 6
Secure deletion of data from magnetic and solid-state memory
SSYM'96 Proceedings of the 6th conference on USENIX Security Symposium, Focusing on Applications of Cryptography - Volume 6
Karma: know-it-all replacement for a multilevel cache
FAST '07 Proceedings of the 5th USENIX conference on File and Storage Technologies
A user-mode port of the linux kernel
ALS'00 Proceedings of the 4th annual Linux Showcase & Conference - Volume 4
HotCloud'09 Proceedings of the 2009 conference on Hot topics in cloud computing
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The layered design of the Linux operating system hides the liveness of file system data from the underlying block layers. This lack of liveness information prevents the storage system from discarding blocks deleted by the file system, often resulting in poor utilization, security problems, inefficient caching, and migration overheads. In this paper, we define a generic "purge" operation that can be used by a file system to pass liveness information to the block layer with minimal changes in the layer interfaces, allowing the storage system to discard deleted data. We present three approaches for implementing such a purge operation: direct call, zero blocks, and flagged writes, each of which differs in their architectural complexity and potential performance overhead. We evaluate the feasibility of these techniques through a reference implementation of a dynamically resizable copy on write (COW) data store in User Mode Linux (UML). Performance results obtained from this reference implementation show that all these techniques can achieve significant storage savings with a reasonable execution time overhead. At the same time, our results indicate that while the direct call approach has the best performance, the zero block approach provides the best compromise in terms of performance overhead and its semantic and architectural simplicity. Overall, our results demonstrate that passing liveness information across the file system-block layer interface with minimal changes is not only feasible but practical.