2,667 research outputs found
RoBuSt: A Crash-Failure-Resistant Distributed Storage System
In this work we present the first distributed storage system that is provably
robust against crash failures issued by an adaptive adversary, i.e., for each
batch of requests the adversary can decide based on the entire system state
which servers will be unavailable for that batch of requests. Despite up to
crashed servers, with constant and
denoting the number of servers, our system can correctly process any batch of
lookup and write requests (with at most a polylogarithmic number of requests
issued at each non-crashed server) in at most a polylogarithmic number of
communication rounds, with at most polylogarithmic time and work at each server
and only a logarithmic storage overhead.
Our system is based on previous work by Eikel and Scheideler (SPAA 2013), who
presented IRIS, a distributed information system that is provably robust
against the same kind of crash failures. However, IRIS is only able to serve
lookup requests. Handling both lookup and write requests has turned out to
require major changes in the design of IRIS.Comment: Revised full versio
Autonomic Management in a Distributed Storage System
This thesis investigates the application of autonomic management to a
distributed storage system. Effects on performance and resource consumption
were measured in experiments, which were carried out in a local area test-bed.
The experiments were conducted with components of one specific distributed
storage system, but seek to be applicable to a wide range of such systems, in
particular those exposed to varying conditions. The perceived characteristics
of distributed storage systems depend on their configuration parameters and on
various dynamic conditions. For a given set of conditions, one specific
configuration may be better than another with respect to measures such as
resource consumption and performance. Here, configuration parameter values were
set dynamically and the results compared with a static configuration. It was
hypothesised that under non-changing conditions this would allow the system to
converge on a configuration that was more suitable than any that could be set a
priori. Furthermore, the system could react to a change in conditions by
adopting a more appropriate configuration. Autonomic management was applied to
the peer-to-peer (P2P) and data retrieval components of ASA, a distributed
storage system. The effects were measured experimentally for various workload
and churn patterns. The management policies and mechanisms were implemented
using a generic autonomic management framework developed during this work. The
experimental evaluations of autonomic management show promising results, and
suggest several future research topics. The findings of this thesis could be
exploited in building other distributed storage systems that focus on
harnessing storage on user workstations, since these are particularly likely to
be exposed to varying, unpredictable conditions.Comment: PhD Thesis, University of St Andrews, 2009. Supervisor: Graham Kirb
Redundancy and Aging of Efficient Multidimensional MDS-Parity Protected Distributed Storage Systems
The effect of redundancy on the aging of an efficient Maximum Distance
Separable (MDS) parity--protected distributed storage system that consists of
multidimensional arrays of storage units is explored. In light of the
experimental evidences and survey data, this paper develops generalized
expressions for the reliability of array storage systems based on more
realistic time to failure distributions such as Weibull. For instance, a
distributed disk array system is considered in which the array components are
disseminated across the network and are subject to independent failure rates.
Based on such, generalized closed form hazard rate expressions are derived.
These expressions are extended to estimate the asymptotical reliability
behavior of large scale storage networks equipped with MDS parity-based
protection. Unlike previous studies, a generic hazard rate function is assumed,
a generic MDS code for parity generation is used, and an evaluation of the
implications of adjustable redundancy level for an efficient distributed
storage system is presented. Results of this study are applicable to any
erasure correction code as long as it is accompanied with a suitable structure
and an appropriate encoding/decoding algorithm such that the MDS property is
maintained.Comment: 11 pages, 6 figures, Accepted for publication in IEEE Transactions on
Device and Materials Reliability (TDMR), Nov. 201
Cooperative Regenerating Codes for Distributed Storage Systems
When there are multiple node failures in a distributed storage system,
regenerating the failed storage nodes individually in a one-by-one manner is
suboptimal as far as repair-bandwidth minimization is concerned. If data
exchange among the newcomers is enabled, we can get a better tradeoff between
repair bandwidth and the storage per node. An explicit and optimal construction
of cooperative regenerating code is illustrated.Comment: 5 pages, 7 figures, to appear in Proc. IEEE ICC, 201
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