15,883 research outputs found
Flexible allocation and space management in storage systems
In this dissertation, we examine some of the challenges faced by the emerging
networked storage systems. We focus on two main issues. Current file systems allocate
storage statically at the time of their creation. This results in many suboptimal
scenarios, for example: (a) space on the disk is not allocated well across multiple
file systems, (b) data is not organized well for typical access patterns. We propose
Virtual Allocation for flexible storage allocation. Virtual allocation separates storage
allocation from the file system. It employs an allocate-on-write strategy, which lets
applications fit into the actual usage of storage space without regard to the configured
file system size. This improves flexibility by allowing storage space to be shared across
different file systems. We present the design of virtual allocation and an evaluation
of it through benchmarks based on a prototype system on Linux.
Next, based on virtual allocation, we consider the problem of balancing locality and load in networked storage systems with multiple storage devices (or bricks).
Data distribution affects locality and load balance across the devices in a networked
storage system. We propose user-optimal data migration scheme which tries to balance locality and load balance in such networked storage systems. The presented
approach automatically and transparently manages migration of data blocks among
disks as data access patterns and loads change over time. We built a prototype system on Linux and present the design of user-optimal migration and an evaluation of
it through realistic experiments
Operating-system support for distributed multimedia
Multimedia applications place new demands upon processors, networks and operating systems. While some network designers, through ATM for example, have considered revolutionary approaches to supporting multimedia, the same cannot be said for operating systems designers. Most work is evolutionary in nature, attempting to identify additional features that can be added to existing systems to support multimedia. Here we describe the Pegasus project's attempt to build an integrated hardware and operating system environment from\ud
the ground up specifically targeted towards multimedia
Elevating commodity storage with the SALSA host translation layer
To satisfy increasing storage demands in both capacity and performance,
industry has turned to multiple storage technologies, including Flash SSDs and
SMR disks. These devices employ a translation layer that conceals the
idiosyncrasies of their mediums and enables random access. Device translation
layers are, however, inherently constrained: resources on the drive are scarce,
they cannot be adapted to application requirements, and lack visibility across
multiple devices. As a result, performance and durability of many storage
devices is severely degraded.
In this paper, we present SALSA: a translation layer that executes on the
host and allows unmodified applications to better utilize commodity storage.
SALSA supports a wide range of single- and multi-device optimizations and,
because is implemented in software, can adapt to specific workloads. We
describe SALSA's design, and demonstrate its significant benefits using
microbenchmarks and case studies based on three applications: MySQL, the Swift
object store, and a video server.Comment: Presented at 2018 IEEE 26th International Symposium on Modeling,
Analysis, and Simulation of Computer and Telecommunication Systems (MASCOTS
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