Efficient Management of Idleness in Storage Systems 1 (2009)
Ningfang Mi, Alma Riska, Qi Zhang, Evgenia Smirni, Erik Riedel
Various activities that intend to enhance performance, reliability, and availability of storage systems are scheduled with low priority and served during storage system idle times. Under such...
Performance-Guided Load (Un)Balancing under Autocorrelated Flows (2009)
Qi Zhang, Ningfang Mi, Student Member, Alma Riska, Evgenia Smirni
Abstract—Size-based policies have been shown in the literature to effectively balance load and improve performance in cluster environments. Size-based policies assign jobs to servers based on the...
Performance-Guided Load (Un)Balancing under Autocorrelated Flows (2009)
Qi Zhang, Ningfang Mi, Student Member, Alma Riska, Evgenia Smirni
Abstract—Size-based policies have been shown in the literature to effectively balance the load and improve performance in cluster environments. Size-based policies assign jobs to servers based on...
Enhancing Data Availability through Background Activities (2009)
Ningfang Mi, Alma Riska, Evgenia Smirni, Erik Riedel
Latent sector errors in disk drives affect only a few data sectors and are often not detected till the affected data is accessed again. They may cause data loss if the storage system is operating...
Enhancing Data Availability in Disk Drives through Background Activities* (2009)
Alma Riska, Evgenia Smimi, Erik Riedel
Latent sector errors in disk drives affect only a few data sectors. They occur silently and are detected only when the affected area is accessed again. Ifa latent error is detected while the storage...
Load Balancing for Performance Differentiation in Dual-Priority Clustered Servers ∗ (2009)
Ningfang Mi, Qi Zhang, Alma Riska, Evgenia Smirni
Size-based policies have been known to successfully balance load and improve performance in homogeneous cluster environments where a dispatcher assigns a job to a server strictly based on the job...
Xi Zhang, Alma Riska, Erik Riedel
This paper characterizes the workload seen at the storage subsystem of an e-commerce system. Measurements are conducted on multi-tiered systems running three different benchmarks, i.e., TPC-W, TPC-C,...
The Penn State University and (2009)
Jianyong Zhang, Anand Sivasubramaniam, Qian Wang, Alma Riska, Erik Riedel
I/O consolidation is a growing trend in production environments due to increasing complexity in tuning and managing storage systems. A consequence of this trend is the need to serve multiple users...
MAMSolver: A matrix analytic methods tool 1 (2009)
2 MAMSolver framework MAMSolver deals with the solution of M/G/1, GI/M/1, and QBD processes. Throughout this exposition, we refer to continuous time Markov processes. However MAMSolver provides...
New Results on the Performance Effects of Autocorrelated Flows in Systems (2009)
Evgenia Smirni, Qi Zhang, Ningfang Mi, Alma Riska, Giuliano Casale
Temporal dependence within the workload of any computing or networking system has been widely recognized as a significant factor affecting performance. More specifically, burstiness, as a form of...
Disk Drive Workload Captured in Logs Collected During the Field Return Incoming Test (2009)
Hard disk drives returned back to Seagate undergo the Field Return Incoming Test. During the test, the available logs in disk drives are collected, if possible. These logs contain cumulative data on...
Idle Read After Write- IRAW (2009)
Despite a low occurrence rate, silent data corruption represents a growing concern for storage systems designers. Throughout the storage hierarchy, from the file system down to the disk drives,...
Bottlenecks and their Performance Implications inE-Commerce Systems (2009)
Qi Zhang, Alma Riska, Erik Riedel, Evgenia Smirni
Abstract. We present a detailed workload characterization of a multi-tiered sys-tem that hosts an e-commerce site. Using the TPC-W workload and via experimental measurements, we illustrate how...
Evaluating the Performability of Systems with Background Jobs ∗ (2008)
Qi Zhang, Alma Riska, Ningfang Mi, Erik Riedel, Evgenia Smirni
As most computer systems are expected to remain operational 24 hours a day, 7 days a week, they must complete maintenance work while in operation. This work is in addition to the regular tasks of the...
Alma Riska, Evgenia Smirni, Gianfranco Ciardo
and GI/M/1-type processes; matrix analytic techniques; stochastic complementation). Summary and Conclusions We present an exact decomposition algorithm for the analysis of Markov chains with a...
Alma Riska, Wei Sun, Evgenia Smirni, Gianfranco Ciardo
effective balancing in clustered web servers under transient load
Andreas Stathopoulos, Alma Riska, Evgenia Smirni, Zhili Hua
solution of M/G/1-type processes
Evaluating Block-level Optimization through the IO Path (2008)
This paper focuses on evaluation of the effectiveness of optimization at various layers of the IO path, such as the file system, the device driver scheduler, and the disk drive itself. IO performance...
ETAQA Solutions for Infinite Markov Processes with Repetitive Structure (2008)
informs ® doi 10.1287/ijoc.1050.0160 © 2007 INFORMS We describe the ETAQA (efficient technique for the solution of quasi birth-death processes) approach for the exact analysis of M/G/1 and...
BRIDGING ETAQA AND RAMASWAMI’S FORMULA FOR THE SOLUTION OF M/G/1-TYPE PROCESSES ∗ (2008)
Andreas Stathopoulos, Alma Riska, Zhili Hua, Evgenia Smirni
For some time, the method of Ramaswami has been the established way to analyze M/G/1-type processes. The ETAQA method, proposed previously in [15], has offered a more efficient alternative for the...
Idle read after write: Iraw (2008)
Despite a low occurrence rate, silent data corruption represents a growing concern for storage systems designers. Throughout the storage hierarchy, from the file system down to the disk drives,...
ETAQA-MG1: An Ecient Technique for the Analysis of M/G/1-type processes by Aggregation (2007)
Gianfranco Ciardo, Weizhen Mao, Alma Riska, Evgenia Smirni
We extend the ETAQA approach, initially proposed for the ecient numerical solution of a class of quasi birth-death processes, to the more complex case of M/G/1-type Markov processes. The new...
Exact analysis of a class of GI/G/1-type performability (2007)
Alma Riska, Evgenia Smirni, Gianfranco Ciardo
models
Managing Overload Via Adaptive Scheduling (2007)
Alma Riska Waterfront, Alma Riska
In this paper, we propose a new adaptive disk scheduling algorithm that assists a disk to maintain its performance while operating in overload. The new scheduling algorithm adapts its parameters to...
Exact analysis of a class of GI/G/1-type performability models (2007)
Alma Riska, Evgenia Smirni, Gianfranco Ciardo
this paper, we consider the solution of a class of CTMCs that show a GI/G/1-type repetitive structure, that is, they exhibit both M/G/1-type and GI/M/1-type patterns, and cannot be solved by existing...
Efficient Fitting of Long-Tailed Data Sets into Hyperexponential Distributions (2007)
Alma Riska, Vesselin Diev, Evgenia Smirni
We propose a new technique for fitting longtailed data sets into hyperexponential distributions. The approach partitions the data set in a divide and conquer fashion and uses the...
Disk drive level workload characterization (2006)
In this paper, we present a characterization of disk drive workloads measured in systems representing the enterprise, desktop, and consumer electronics environments. We observe that the common...
Load unbalancing to improve performance under autocorrelated traffic (2006)
Qi Zhang, Ningfang Mi, Alma Riska, Evgenia Smirni
Size-based policies have been shown to successfully balance load and improve performance in homogeneous cluster environments where a dispatcher assigns a job to a server strictly based on the job...
Evaluating the performability of systems with background jobs (2006)
Qi Zhang, Alma Riska, Ningfang Mi, Evgenia Smirni
As most computer systems are expected to remain operational 24 hours a day, 7 days a week, they must complete maintenance work while in operation. This work is in addition to the regular tasks of the...
Long-range dependence at the disk drive level (2006)
Alma.Riska @ seagate.com Erik.Riedel @ seagate.com Nowadays, the need for storage devices arises in a wide range of computer and electronic devices such as enterprise systems, personal computers, and...
Workload-aware load balancing for clustered web servers (2005)
Qi Zhang, Alma Riska, Wei Sun, Evgenia Smirni, Gianfranco Ciardo, Senior Member
Abstract—We focus on load balancing policies for homogeneous clustered Web servers that tune their parameters on-the-fly to adapt to changes in the arrival rates and service times of incoming...
Workload-aware load balancing for clustered web servers (2005)
Qi Zhang, Alma Riska, Wei Sun, Evgenia Smirni, Gianfranco Ciardo
Abstract We focus on load balancing policies for clustered web servers that tune their parameters on-the-fly to adapt to changes in the arrival rates and service times of incoming requests. The...
a class of M/G/1-type processes by aggregation (2005)
Gianfranco Ciardo, Weizhen Mao, Alma Riska, Evgenia Smirni
An efficient technique for the analysis of
Workload-aware load balancing for clustered web servers (2005)
Qi Zhang, Alma Riska, Wei Sun, Evgenia Smirni, Gianfranco Ciardo
We focus on load balancing policies for homogeneous clustered web servers that tune their parameters on-the-fly to adapt to changes in the arrival rates and service times of incoming requests. The...
Workload-aware load balancing for clustered web servers (2005)
Qi Zhang, Alma Riska, Wei Sun, Evgenia Smirni, Gianfranco Ciardo
We focus on load balancing policies for clustered web servers that tune their parameters on-the-fly to adapt to changes in the arrival rates and service times of incoming requests. The proposed...
Workload propagation – overload in bursty servers (2005)
Qi Zhang, Alma Riska, Erik Riedel
Internet servers are developing into complex but central components in the information infrastructure and are accessed by an ever-increasing and diversified user population. As such, they are...
Workload-aware load balancing for clustered web servers (2005)
Qi Zhang, Alma Riska, Wei Sun, Evgenia Smirni, Gianfranco Ciardo, Senior Member
Abstract—We focus on load balancing policies for homogeneous clustered Web servers that tune their parameters on-the-fly to adapt to changes in the arrival rates and service times of incoming...
Gianfranco Ciardo, Weizhen Mao, Alma Riska, Evgenia Smirni
We extend the Etaqa approach, initially proposed for the efficient numerical solution of a class of quasi-birth–death processes, to a more complex class of M/G/1-type Markov processes where...
Susceptibility of commodity systems and software to memory soft errors (2004)
Alan Messer, Guangrui Fu, Deqing Chen, Zoran Dimitrijevic, David Lie, Durga Devi Mannaru, ...
Abstract — It is widely understood that most system downtime is accounted for by programming errors and administration time. However, a growing body of work has indicated an increasing cause of...
Bottlenecks and their performance implications in e-commerce systems (2004)
Qi Zhang, Alma Riska, Erik Riedel, Evgenia Smirni
Abstract. We present a detailed workload characterization of a multi-tiered system that hosts an e-commerce site. Using the TPC-W workload and via experimental measurements, we illustrate how...
Adaptive disk scheduling for overload management (2004)
Alma Riska, Erik Riedel, Sami Iren
Most computer systems today are lightly loaded in normal operation. The real performance problems occur during burst times when the system becomes overloaded. We evaluate how the choice of scheduling...
Bottlenecks and their performance implications in e-commerce systems (2004)
Qi Zhang, Alma Riska, Erik Riedel, Evgenia Smirni
Abstract. We present a detailed workload characterization of a multi-tiered system that hosts an e-commerce site. Using the TPC-W workload and via experimental measurements, we illustrate how...
An EM-based technique for approximating long-tailed data sets with PH distributions (2003)
Alma Riska, Vesselin Diev, Evgenia Smirni
We propose a new technique for tting long-tailed data sets into phase-type (PH) distributions. This technique ts data sets with non-monotone densities into a mixture of Erlang and hyperexponential...
It’s not fair - evaluating efficient disk scheduling (2003)
Storage system designers prefer to limit the maximum queue length at individual disks to only a few outstanding requests, to avoid possible request starvation. In this paper, we evaluate the benefits...
M/G/1-type Markov processes: A tutorial (2002)
Abstract. M/G/1-type processes are commonly encountered when modeling modern complex computer and communication systems. In this tutorial, we present a detailed survey of existing solution methods...
ADAPTLOAD: effective balancing in clustered Web servers under transient load conditions (2002)
Alma Riska, Wei Sun, Evgenia Smirni, Gianfranco Ciardo
conditions
MAMSolver: A matrix analytic methods tool (2002)
MAMsolver is a software tool for the solution of M/G/1type, GI/M/1-type, and QBD processes. The collection of solution algorithms implemented by MAMsolver are known as matrix-analytic methods and are...
M/G/1-type Markov Processes: A tutorial (2002)
M/G/1-type processes are commonly encountered when modeling modern complex computer and communication systems. In this tutorial, we present a detailed survey of existing solution methods for...
Exact Aggregate Solutions for M/G/1-type Markov Processes (2002)
We introduce a new methodology for the exact analysis of M/G/1-type Markov processes. The methodology uses basic, well-known results for Markov chains by exploiting the structure of the repetitive...
ADAPTLOAD: effective balancing in clustered web servers under transient load (2002)
Conditions Alma Riska, Alma Riska, Wei Sun, Evgenia Smirni, Gianfranco Ciardo
We focus on adaptive policies for load balancing in clustered web servers, based on the size distribution of the requested documents. The proposed scheduling policy, ADAPTLOAD, adapts its balancing...
EQUILOAD: a load balancing policy for clustered Web servers. Performance Evaluation (2001)
Gianfranco Ciardo, Alma Riska, Evgenia Smirni
We present a new strategy for the allocation of requests in clustered web servers, based on the size distribution of the requested documents. This strategy, EquiLoad, manages to achieve a balanced...
EQUILOAD: a load balancing policy for clustered Web servers. Performance Evaluation (2001)
Gianfranco Ciardo, Alma Riska, Evgenia Smirni
We present a new strategy for the allocation of requests in clustered web servers, based on the size distribution of the requested documents. This strategy, EquiLoad, manages to achieve a balanced...
EQUILOAD: a load balancing policy for clustered Web servers. Performance Evaluation (2001)
Gianfranco Ciardo, Alma Riska, Evgenia Smirni
We present a new strategy for the allocation of requests in clustered web servers, based on the size distribution of the requested documents. This strategy, EquiLoad, manages to achieve a balanced...
EQUILOAD: a load balancing policy for clustered Web servers. Performance Evaluation (2001)
Gianfranco Ciardo, Alma Riska, Evgenia Smirni
We present a new strategy for the allocation of requests in clustered web servers, based on the size distribution of the requested documents. This strategy, EquiLoad, manages to achieve a balanced...
Susceptibility of modern systems and software to soft errors (2001)
David Lie, Alan Messer, Alan Messer, Guangrui Fu, Guangrui Fu, Deqing Chen, ...
It is widely understood that most downtime is accounted for by programming errors and administration time. However, recent work has indicated an increasing cause of downtime may stem from transient...
JVM Susceptibility to Memory Errors (2001)
Deqing Chen, Alan Messer, Guangrui Fu, Zoran Dimitrijevic, Durga Mannaru, Alma Riska, ...
Modern systems are getting more powerful and using larger memories. However, except at the very high end systems, much less attention is being paid to high availability. This is particularly the case...
Analytic modeling of load balancing policies for tasks with heavy-tailed distributions (2000)
Alma Riska, Evgenia Smirni, Gianfranco Ciardo
We present an analytic technique for modeling load balancing policies on a cluster of servers conditioned on the fact that the service times of arriving tasks are drawn from heavy tail distributions....
Analytic modeling of load balancing policies for tasks with heavy-tailed distributions (2000)
Alma Riska, Evgenia Smirni, Gianfranco Ciardo
Abstract We present an analytic technique for modeling load balancing policies on a cluster of servers conditioned on the fact that the arriving tasks are drawn from heavy tail distributions. We...
Analytic modeling of load balancing policies for tasks with heavy-tailed distributions (2000)
Alma Riska, Evgenia Smirni, Gianfranco Ciardo
We present an analytic technique for modeling load balancing policies on a cluster of servers conditioned on the fact that the service times of arriving tasks are drawn from heavy tail distributions....
Analytic modeling of load balancing policies for tasks with heavy-tailed distributions (2000)
Alma Riska, Evgenia Smirni, Gianfranco Ciardo
We present an analytic technique for modeling load balancing policies on a cluster of servers conditioned on the fact that the service times of arriving tasks are drawn from heavy tail distributions....
An aggregation-based solution method for M/G/1-type processes (1999)
Gianfranco Ciardo, Alma Riska, Evgenia Smirni
Abstract. We extend the ETAQA approach, initially proposed for the efficient numerical solution of a class of quasi birth-death processes, to the more complex case of M/G/1-type Markov processes. The...
An aggregation-based solution method for M/G/1-type processes (1999)
Gianfranco Ciardo, Alma Riska, Evgenia Smirni
Abstract. We extend the ETAQA approach, initially proposed for the ecient numerical solution of a class of quasi birth-death processes, to the more complex case of M/G/1-type Markov processes. The...
An aggregation-based solution method for M/G/1-type processes (1999)
Gianfranco Ciardo, Alma Riska, Evgenia Smirni
. We extend the ETAQA approach, initially proposed for the efficient numerical solution of a class of quasi birth-death processes, to the more complex case of M/G/1-type Markov processes. The...
An aggregation-based solution method for M/G/1-type processes (1999)
Gianfranco Ciardo, Alma Riska, Evgenia Smirni
We extend the ETAQA approach, initially proposed for the efficient numerical solution of a class of quasi birth-death processes, to the more complex case of M/G/1-type Markov processes. The proposed...
Alma Riska, Vesselin Diev, Evgenia Smirni
We propose a new technique for fitting long-tailed data sets into phase-type (PH) distributions. This technique fits data sets with non-monotone densities into a mixture of Erlang and...