Wednesday, 23 July 2014
Ensuring the Performance of Apache HTTP Server Affected by Aging
ENSURING THE PERFORMANCE OF APACHE HTTP SERVER AFFECTED BY AGING
Failures due to software aging are typically caused by resource exhaustion, which is often preceded by progressive software performance degradation. Response time as a customer-affecting metric can thus be used to detect the onset of software aging. In this paper, we propose the distribution-based rejuvenation algorithm (DBRA), which uses a validated M=E2=1=K queuing model of the Apache HTTP server to decide when to trigger rejuvenation. We compare the performance of the DBRA with the one of the static rejuvenation algorithm with averaging (SRAA) presented by Avritzer et al. Simulation results show the effectiveness of the DBRA and its advantages over the SRAA in reducing the average response time. However, the DBRA generally tends to trigger rejuvenation more frequently than the SRAA, which increases the request blocking probability.
IT is well known that system outages are more due to software faults than due to hardware faults. Software faults have been classified into three types according to their potential manifestation characteristics: Bohrbugs, nonaging-related Mandelbugs, and aging-related bugs. Software aging is the phenomenon of progressive performance degradation of the running software, which may lead to system crashes or undesirable hangs. It can happen due to the exhaustion of system resources, such as memory leaks, unreleased locks, nonterminated threads, shared-memory pool latching, storage fragmentation, and the like. This undesired phenomenon exists not only in commercial software, such as Web and application servers, but also in critical applications requiring high reliability/ availability. Software aging could also cause great losses in safety-critical systems, including the loss of human lives. It does not make software fail immediately once started, but instead it typically leads to the accumulation of internal error conditions, which is often accompanied by progressive performance degradation of the software until it, finally, hangs or crashes.
DISADVANTAGES OF EXISTING SYSTEM:
v It could also cause great losses in safety-critical systems.
v It allows degradation of the running software, which may lead to system crashes or undesirable hangs.
To counteract software aging, we proposed a proactive approach called software rejuvenation. It involves occasionally stopping the software, cleaning its internal state, and restarting it to release system resources, so that the software performance is recovered. Thus, software rejuvenation mends the system before it fails. First, we numerically obtain the quantile of the exact average RT distribution for a given degree of confidence using the SHARPE tool. Second, we propose the DBRA employing
this quantile to detect aging and control rejuvenation. Third, we develop a simulation program to validate the DBRA and to compare the effectiveness of the DBRA and the SRAA under different control parameters.
ADVANTAGES OF PROPOSED SYSTEM:
v Its derive closed-form analytical expressions for the steady state probabilities of the model.
v It numerically obtains quintiles’ of the distribution of average RT to decide when to rejuvenate.
Speed - 1.1 Ghz
RAM - 512 MB(min)
Hard Disk - 40 GB
Key Board - Standard Windows Keyboard
Mouse - Two or Three Button Mouse
Monitor - LCD/LED
Operating system : Windows XP.
Coding Language : JAVA
Data Base : MySQL
Tool : Netbeans.
Jing Zhao, Kishor S. Trivedi Michael Grottke, Javier Alonso, and Yanbin Wang, “Ensuring the Performance of Apache HTTP Server Affected by Aging” IEEE TRANSACTIONS ON DEPENDABLE AND SECURE COMPUTING, VOL. 11, NO. 2, MARCH/APRIL 2014.