Techniques for web server management

Techniques for provisioning and decommissioning web servers in an automated manner. In one embodiment, a threshold value relating to an operational metric of a web server can be stored. The metric can be monitored as the web server receives requests. If the metric exceeds the threshold value, additional web servers can be automatically provisioned to handle a portion of the requests. If the metric falls below the threshold value, the additional web servers can be automatically decommissioned. In another embodiment, information can be logged pertaining to web server requests received over time. Based on this information and a threshold value, patterns of high/low server load can be determined and a policy can be generated identifying time intervals during which additional web servers should be provisioned (or existing web servers should be decommissioned). The policy can be used at server runtime to provision or decommission web servers at the identified intervals.

BACKGROUND

The present disclosure relates in general to web server management, and in particular to techniques for provisioning and decommissioning web servers in an automated manner.

In current practice, server resources for a web site are generally provisioned in a manual fashion. For example, in a typical deployment scenario, an administrator for a web site will estimate an average amount of traffic that the web site is expected to receive (e.g., ten thousand requests per day). The administrator will then manually provision a number of web servers for the web site based upon the estimate.

While the above approach is serviceable if the amount of traffic received by a web site is relatively stable, it can be problematic if the web site experiences spikes where the amount of traffic significantly exceeds or falls under the expected amount. For example, during times of extremely high traffic, the web servers provisioned for the web site can become so overloaded with requests that they fail to service all of the requests successfully. This can lead to denial of service for clients. As another example, during times of extremely low traffic, the web servers provisioned for the web site can become under-utilized, leading to a waste of server resources. To address these issues, an administrator of the web site can try to manually reconfigure the number of web servers provisioned for the web site when traffic spikes occur. However, such manual reconfiguration is cumbersome and typically cannot be performed quickly enough to completely avoid denial of service (at times of high traffic) or under-utilization of resources (at times of low traffic).

Accordingly, it is desirable to have improved techniques for provisioning server resources for a web site.

BRIEF SUMMARY

Embodiments of the present invention provide techniques for provisioning and decommissioning web servers in an automated manner. In certain embodiments, the techniques described herein can ensure uninterrupted servicing of client requests while facilitating optimal utilization of web server resources, thereby overcoming the issues associated with manual web server provisioning.

In one set of embodiments, a threshold value can be stored that relates to an operational metric of a web server (e.g., number of requests received per unit time, CPU utilization, etc.). The metric can be monitored as the web server receives requests. If the metric exceeds the threshold value, additional web servers can be automatically provisioned to handle a portion of the requests. If the metric subsequently falls below the threshold value, the additional web servers can be automatically decommissioned. In this manner, web server resources can be dynamically allocated or de-allocated based on real-time traffic.

In another set of embodiments, information can be logged that pertains to requests received by a web server over a period of time. Based on the logged information and a threshold value, patterns of high and/or low server load can be determined and a policy can be generated identifying recurring time intervals during which additional web servers should be provisioned (or existing web servers should be decommissioned). The policy can be used at server runtime to provision or decommission web servers at the identified intervals. In this manner, web server resources can be dynamically allocated and de-allocated based on historic traffic patterns.

In either of the embodiments described above, the threshold value can be received from a user (e.g., a web site administrator) or determined automatically by the web server.

According to one embodiment of the present invention, a method is provided comprising storing, by a computer system, a threshold value for an operational metric of a web server and monitoring, by the computer system, the metric as requests are received by the web server. If the metric exceeds the threshold value, the method further comprises provisioning, by the computer system, one or more additional web servers and routing, by the computer system, a portion of the requests to the one or more additional web servers.

In one embodiment, if the metric subsequently falls below the threshold value, the method further comprises decommissioning, by the computer system, the one or more additional web servers.

In one embodiment, the threshold value is provided by a user. In another embodiment, the threshold value is determined automatically by the computer system.

In the case where the threshold value is determined automatically, the determining comprises logging information related to a plurality of requests received by the web server over a period of time and applying one or more heuristics-based rules to the logged information.

According to another embodiment of the present invention, a method is provided comprising logging, by a computer system, information related to a plurality of requests received by a web server over a period of time and determining, by the computer system, a pattern of high web server load based on the logged information and a threshold value. The threshold value represents a value for an operational metric of the web server that, when exceeded, indicates high web server load. The method further comprises generating, by the computer system, a policy based on the pattern of high web server load, where the policy indicates a recurring time interval during which one or more additional web servers should be provisioned.

In one embodiment, the method further comprises, subsequent to generating the policy, provisioning one or more additional web servers when the recurring time interval arrives and routing a portion of requests received by the web server to the one or more additional web servers during the recurring time interval. In a further embodiment, the one or more additional web servers are decommissioned once the recurring time interval has passed.

In one embodiment, the threshold value is provided by a user. In another embodiment, the threshold value is determined automatically by the computer system. In the latter embodiment, the threshold value is determined by applying one or more heuristics-based rules to the logged information.

In one embodiment, determining the pattern of high web server load comprises processing the logged information using a heuristics-based pattern matching algorithm. In one embodiment, this processing is performed by a complex event processing server.

According to another embodiment of the present invention, a computer readable storage medium is provided that has stored thereon instructions executable by a computer system, the instructions comprising instructions that cause the computer system to store a threshold value for an operational metric of a web server and instructions that cause the computer system to monitor the metric as requests are received by the web server. The instructions further comprise instructions that cause the computer system to, if the metric exceeds the threshold value, provision one or more additional web servers and route a portion of the requests to the one or more additional web servers.

According to another embodiment of the present invention, a computer readable storage medium is provided that has stored thereon instructions executable by a computer system, the instructions comprising instructions that cause the computer system to log information related to a plurality of requests received by a web server over a period of time and instructions that cause the computer system to determine a pattern of high web server load based on the logged information and a threshold value. The threshold value represents a value for an operational metric of the web server that, when exceeded, indicates high web server load. The instructions further comprise instructions that cause the computer system to generate a policy based on the pattern of high web server load, where the policy indicates a recurring time interval during which one or more additional web servers should be provisioned.

A further understanding of the nature and advantages of the embodiments disclosed herein can be realized by reference to the remaining portions of the specification and the attached drawings.

DETAILED DESCRIPTION

In the following description, for the purposes of explanation, numerous details are set forth in order to provide an understanding of various embodiments of the present invention. It will be apparent, however, to one skilled in the art that certain embodiments can be practiced without some of these details.

Embodiments of the present invention provide techniques for provisioning and decommissioning web servers in an automated manner. In certain embodiments, the techniques described herein can ensure uninterrupted servicing of client requests while facilitating optimal utilization of web server resources, thereby overcoming the issues associated with manual web server provisioning.

In one set of embodiments, a threshold value can be stored that relates to an operational metric of a web server (e.g., number of requests received pre unit time, CPU utilization, etc.). The metric can be monitored as the web server receives requests. If the metric exceeds the threshold value, additional web servers can be automatically provisioned to handle a portion of the requests. If the metric subsequently falls below the threshold value, the additional web servers can be automatically decommissioned. In this manner, web server resources can be dynamically allocated or de-allocated based on real-time traffic.

In another set of embodiments, information can be logged that pertains to requests received by a web server over a period of time. Based on the logged information and a threshold value, patterns of high and/or low server load can be determined and a policy can be generated identifying recurring time intervals during which additional web servers should be provisioned (or existing web servers should be decommissioned). The policy can be used at server runtime to provision or decommission web servers at the identified intervals. In this manner, web server resources can be dynamically allocated and de-allocated based on historic traffic patterns.

In either of the embodiments described above, the threshold value can be received from a user (e.g., a web site administrator) or determined automatically by the web server.

FIG. 1is a simplified block diagram of a web server system100according to an embodiment of the present invention. As shown, system100can include a primary web server102communicatively coupled with a storage component104. Primary web server102can be a software and/or hardware-based module that is configured to receive Hypertext Transfer Protocol (HTTP) requests from clients accessing a web resource (e.g., a website) and to service those requests by returning HTTP responses to the clients. In a particular embodiment, primary web server102can be an instance of Oracle HTTP Server, a web server software application developed by Oracle Corporation. Storage component104can be any type of storage device (or combination of devices) suitable for storing data accessed by primary web server102.

In one set of embodiments, primary web server102can include a management daemon106configured to monitor the server's operation as it receives and processes client requests. For example, management daemon106can monitor, in real-time, a value for an operational metric of primary web server102such as the number of requests received per unit time, CPU utilization, number of running threads, number of bytes transferred, or the like. As the metric is being monitored, management daemon106can compare the real-time value of the metric to a threshold value108stored in storage component104. Threshold value108can represent a value for the metric that, when exceeded, indicates heavy web server traffic (and thus high web server load). For instance, a threshold value of “80%” for the CPU utilization metric can indicate that any CPU utilization percentage over 80% represents an excessive load on primary web server102.

If the real-time value of the metric exceeds threshold value108, management daemon106can automatically provision one or more backup web servers (e.g.,110and112).

Primary web server102can then redirect a portion of the requests it receives to the backup web servers for processing. If the metric subsequently falls back below threshold value108, management daemon106can automatically decommission the backup web servers. In this manner, additional server resources can be dynamically allocated or de-allocated in response to the real-time load on primary web server102, thereby ensuring uninterrupted servicing of client requests (in the case of high web server load) and avoiding under-utilization of resources (in the case of low web server load).

In one set of embodiments, threshold value108can be provided by an administrator of primary web server102or some other individual. This approach may be appropriate in situations where the administrator has an understanding of the performance characteristics of primary web server102and a sense of what a suitable threshold value should be.

In alternative embodiments, threshold value108can be automatically determined by primary web server102. In these embodiments, primary web server102can include a traffic analysis module114that is configured to log data about incoming requests to server102, as well as various runtime statistics (e.g., CPU utilization, number of requests that timeout due to unavailability of resources, etc.). This data can be logged over a period of time and stored in storage component104(e.g., as logged data116). Once sufficient data has been collected, management daemon106can analyze logged data116and apply a set of heuristics-based threshold determination rules (e.g., rules118) to determine an appropriate threshold value for one or more operational metrics of primary web server102. The determined threshold value can then be used as described above to dynamically allocate or de-allocate backup web servers at runtime.

It should be appreciated thatFIG. 1is illustrative and not intended to limit embodiments of the present invention. For example, although management daemon106and traffic analysis module114are shown as being part of primary web server102, one or both of these components can be standalone components that are separate from server102. Further, the various components of system100may each have additional capabilities or include sub-components that are not specifically described. One of ordinary skill in the art will recognize many variations, modifications, and alternatives.

FIG. 2is a flow diagram of a process200for automatically provisioning and decommissioning web servers based on real-time traffic according to an embodiment of the present invention. In one set of embodiments, process200can be carried out by primary web server102(and more specifically, management daemon106) ofFIG. 1. Process200can be implemented in hardware, software, or a combination thereof As software, process200can be encoded as program code stored on a machine-readable storage medium.

At block202, a threshold value (e.g., threshold value108) can be stored for an operational metric of primary web server102. The operational metric can be any attribute or statistic that pertains to the runtime operation of primary web server102, such as the number of requests received by the server per unit time, CPU utilization, number of running threads, number of bytes transferred, and the like. The threshold value can represent a value for the metric that, when exceeded, indicates heavy web server traffic (and thus high web server load). Conversely, the threshold value can represent a value for the metric that, when not exceeded, indicates light or normal web server traffic (and thus low or moderate web server load). As discussed above, in some embodiments the threshold value can be provided by an administrator of primary web server102or some other individual. In other embodiments, the threshold value can be determined automatically based on logged web server data (e.g., logged data116) and a set of heuristics-based rules (e.g., rules118). The process for automatically determining a threshold value is discussed in greater detail with respect toFIG. 3below.

At block204, management daemon106can monitor the operational metric as requests are received and processed by primary web server102. As part of this monitoring, the real-time value of the metric can be compared to the threshold value stored at block202. If the real-time value of the metric exceeds the threshold value, it is likely that the current load on primary web server102is too high for the server to adequately service all incoming requests. Accordingly, one or more additional web servers (e.g., backup web servers110and112) can be automatically provisioned by management daemon106, and a portion of the requests received by primary web server102can be routed to the backup web servers (block206). By provisioning these additional backup web servers, the load on primary web server102can be reduced and incoming client requests can be serviced without interruption.

In some embodiments, when backup web servers110and112are provisioned per block206, all of the requests received by primary web server102can be redirected to the backup web servers. In these embodiments, primary web server102essentially acts as a proxy server/load balancer while backup web servers110and112are operational. Primary web server102can determine how to redirect the requests using known load balancing techniques. In alternative embodiments, primary web server102can continue to service a portion of the incoming requests while routing the excess traffic that it cannot handle to backup web servers110and112.

In certain embodiments, the number of backup web servers that are provisioned at block206can be predetermined; in other embodiments, the number of backup servers that are provisioned can vary based on the extent to which the threshold value is exceeded. Although two backup web servers are shown inFIG. 1, it should be appreciated that any number of backup web servers can be supported.

While backup web servers110and112are in use, the operational metric of primary web server102can be continually monitored. If the metric falls back below the threshold value, it is likely that the backup web servers are no longer required. Accordingly, backup web servers110and112can be automatically decommissioned and primary web server102can resume servicing of all incoming requests (block208). In this manner, the amount of provisioned server resources can be automatically kept in line with the actual traffic load.

It should be appreciated that process200is illustrative and that variations and modifications are possible. Steps described as sequential may be executed in parallel, order of steps may be varied, and steps may be modified, combined, added, or omitted. One of ordinary skill in the art would recognize many variations, modifications, and alternatives.

As discussed above, in certain embodiments the threshold value used to determine when backup web servers should be provisioned can be automatically determined by the primary web server (rather than being specified by a user).FIG. 3is a flow diagram of a process300for automatically determining such a threshold value according to an embodiment of the present invention. In one set of embodiments, process300can be carried out by primary web server102(and more specifically, traffic analysis module114and management daemon106) ofFIG. 1. Process300can be implemented in hardware, software, or a combination thereof. As software, process300can be encoded as program code stored on a machine-readable storage medium.

At block302, traffic analysis module114can log data related to requests received by primary web server102over a period of time (e.g., a week, a month, a year, etc.). For instance, the logged data can include, for each request, the particular resource being requested, the time at which the request was received, and various statistics of primary web server102as of that time (e.g., CPU utilization, response time, number of requests that have timed out, etc.).

After a sufficient amount of data has been logged, management daemon106can apply a set of heuristics-based rules to the logged data to determine an appropriate threshold value (block304). For example, one such rule may indicate that an appropriate threshold value for CPU utilization is the value at which response time (e.g., the time it takes to return a response to a client) exceeds five seconds. Thus, management daemon106can apply this rule by identifying, in the logged data, historical values for CPU utilization at times when the response time exceeded five seconds. These historical values can then be averaged (or processed in some other manner) to generate a threshold value for CPU utilization (block306).

In one set of embodiments, the processing of blocks304and306can carried out by management daemon106at runtime of primary web server102. In other embodiments, the processing can be carried out by management daemon106as an offline process. In certain embodiments, the processing of blocks304and306can be re-executed by management daemon106on a periodic basis as new data is logged by traffic analysis module114.

It should be appreciated that process300is illustrative and that variations and modifications are possible. Steps described as sequential may be executed in parallel, order of steps may be varied, and steps may be modified, combined, added, or omitted. One of ordinary skill in the art would recognize many variations, modifications, and alternatives.

FIG. 4is a simplified block diagram of a second web server system400according to an embodiment of the present invention. As shown, system400includes components that are similar to system100ofFIG. 1, such as primary web server102(comprising management daemon106and traffic analysis module114), storage component104(comprising threshold value108, logged data116, and threshold determination rules118), and backup web servers110and112. System400can also include additional components (pattern matching module402and policies404) that allow for the automatic provisioning and decommissioning of web servers based on historical traffic patterns (rather than, or in addition to, real-time traffic).

In one set of embodiments, traffic analysis module114is configured to log data about requests received by primary web server102. The data collected is similar to block302ofFIG. 3and can include, for each request, the particular resource being requested, the time at which the request was received, and various statistics of primary web server102as of that time (e.g., CPU utilization, response time, number of requests that have timed out, etc.). This data can be logged over a period of time and stored in storage component104(e.g., as logged data116).

Once sufficient data has been logged, management daemon106is configured to analyze the logged data to determine recurring time intervals of heavy web server traffic (and thus, high load on primary web server102). In certain embodiments, this analysis can be based on a threshold value for an operational metric of primary web server102(e.g., threshold value108), and can involve identifying time intervals in the logged data where the metric exceeds the threshold. In a particular embodiment, this identification can be performed via a heuristics-based pattern matching module such as module402. Management daemon106can then generate a policy404indicating that backup web servers should be provisioned during the identified time intervals.

Once policy404has been generated, management daemon106can apply the policy at runtime of primary web server102. For example, if the policy indicates that high server load typically occurs on Mondays from noon to 2 PM, management daemon106can automatically provision backup web servers110and112every Monday at noon. Primary web server102can then route incoming requests to the backup web servers during this time interval. Once the time interval has passed, management daemon106can automatically decommission the backup web servers. In this manner, server resources can be dynamically allocated and de-allocated based on historical traffic patterns (which will typically indicate future traffic patterns).

It should be appreciated thatFIG. 4is illustrative and not intended to limit embodiments of the present invention. For example, although management daemon106, traffic analysis module114, and pattern matching module402are shown as being part of primary web server102, one or more of these components can be standalone components that are separate from server102. Further, the various components of system400may each have additional capabilities or include sub-components that are not specifically described. One of ordinary skill in the art will recognize many variations, modifications, and alternatives.

FIG. 5is a flow diagram of a process500for automatically provisioning and decommissioning web servers based on historical traffic patterns according to an embodiment of the present invention. In one set of embodiments, process500can be carried out by primary web server102(and more specifically, traffic analysis module114, management daemon106, and pattern matching module402) ofFIG. 4. Process500can be implemented in hardware, software, or a combination thereof. As software, process500can be encoded as program code stored on a machine-readable storage medium.

At block502, traffic analysis module114can log data related to requests received by primary web server102over a period of time (e.g., a week, a month, a year, etc.). As discussed above, this logged data can include, for each request, the particular resource being requested, the time at which the request was received, and various statistics of primary web server102as of that time (e.g., CPU utilization, response time, number of requests that have timed out, etc.).

At block504, management daemon106can determine, based on the logged data and a threshold value (e.g., threshold value108), recurring time intervals of heavy web server traffic (and thus high web server load). For instance, management daemon106can determine that high server load typically occurs on Mondays from noon to 2 PM because CPU utilization commonly exceeds 80% during that time interval, and because the threshold value for the CPU utilization metric is “80%”. To identify such patterns, management daemon106can, in some embodiments, rely on a module that uses heuristics-based pattern matching algorithms to find patterns in data streams (e.g., pattern matching module402). An example of such a module is the Oracle Complex Event Processing Server developed by Oracle Corporation. At block506, management daemon106can generate a policy (e.g., policy404) that specifies the recurring time intervals determined at block504.

In one set of embodiments, the processing of blocks504and506can carried out by management daemon106at runtime of primary web server102. In other embodiments, the processing can be carried out by management daemon106as an offline process.

In yet further embodiments, the processing of blocks504and506can be re-run by management daemon106on a periodic basis to account for changes in web server load patterns over time. For instance, new data can be logged and new policies can be generated every week, month, quarter, year, etc.

Like process200ofFIG. 2, the threshold value used at block504can either be provided by a user or automatically determined by primary web server102. In the latter case, prior to analyzing the logged data to determine time intervals of high web server load, management daemon106can first analyze the logged data and apply a set of heuristics-based rules to determine an appropriate threshold value for one or more operational metrics of primary web server102(similar to blocks304,306ofFIG. 3). The determined threshold value can then be used as part of the processing of block504.

At block508, management daemon106can apply the policy generated at block504at runtime of primary web server102. For example, if the policy indicates that high server load typically occurs on Mondays from noon to 2 PM, management daemon106can automatically provision backup web servers (e.g., backup web servers110and112) every Monday at noon. Primary web server102can then route a portion of the requests it receives to the backup web servers during this time interval (block510). Once the time interval has passed, management daemon106can automatically decommission the backup web servers (block512).

In some embodiments, when backup web servers110and112are provisioned per block508, all of the requests received by primary web server102can be redirected to the backup web servers. In these embodiments, primary web server102essentially acts as a proxy server/load balancer while backup web servers110and112are operational. Primary web server102can determine how to redirect the requests using known load balancing techniques. In alternative embodiments, primary web server102can continue to service a portion of the incoming requests while routing the excess traffic that it cannot handle to backup web servers110and112.

In certain embodiments, the number of backup web servers that are provisioned at block508can be static; in other embodiments, this number can change based on the particular time interval. For instance, it may be determined that two backup web servers are required on Mondays from noon to 2 PM, but four backup web servers are required on Wednesdays from 8 PM to 10 PM. Although two backup web servers are shown inFIG. 4, it should be appreciated that any number of backup web servers can be supported.

It should be appreciated that process500is illustrative and that variations and modifications are possible. Steps described as sequential may be executed in parallel, order of steps may be varied, and steps may be modified, combined, added, or omitted. One of ordinary skill in the art would recognize many variations, modifications, and alternatives.

FIG. 6is a simplified block diagram illustrating a system environment600that may be used in accordance with an embodiment of the present invention. As shown, system environment600includes client computing devices602,604,606,608communicatively coupled with server computers610,612,614via a network616. In one set of embodiments, client computing devices602,604,606,608can each be configured to run a web browser or other client application for requesting web resources from server computers610,612,614. Server computers610,612,614can each be configured to run an instance of a web server (e.g., primary web server102, backup web server110, or backup web server112ofFIG. 1) for servicing requests received from client computing devices602,604,606,608. Although system environment600is shown with four client computing devices and three server computers, any number of client computing devices and server computers may be supported.

Client computing devices602,604,606,608can be general purpose personal computers (including, for example, personal computers and/or laptop computers running various versions of Microsoft Windows and/or Apple Macintosh operating systems), cell phones or PDAs (running software such as Microsoft Windows Mobile and being Internet, e-mail, SMS, Blackberry, and/or other communication protocol enabled), and/or workstation computers running any of a variety of commercially-available UNIX or UNIX-like operating systems (including without limitation the variety of GNU/Linux operating systems). Alternatively, client computing devices602,604,606,608can be any other electronic device capable of communicating over a network (e.g., network612described below) with server computers610,612,614.

Server computers610,612,614can be general purpose computers, specialized server computers (including, e.g., LINUX servers, UNIX servers, mid-range servers, mainframe computers, rack-mounted servers, etc.), server farms, server clusters, or any other appropriate arrangement and/or combination. Server computers610,612,614can run an operating system including any of those discussed above, as well as any commercially available server operating system. Server computers610,612,614can also run any of a variety of server applications and/or middle-tier applications, including web servers, Java virtual machines, application servers, database servers, and the like. As indicated above, in one set of embodiments, server computers610,612,614are each adapted to run a web server and associated software for servicing requests from client computing devices602,604,606,608.

As shown, client computing devices602,604,606,608and server computers610,612,614are communicatively coupled via network616. Network616can be any type of network that can support data communications using any of a variety of commercially-available protocols, including without limitation TCP/IP, SNA, IPX, AppleTalk, and the like. Merely by way of example, network616can be a local area network (LAN), such as an Ethernet network, a Token-Ring network and/or the like; a wide-area network; a virtual network, including without limitation a virtual private network (VPN); the Internet; an intranet; an extranet; a public switched telephone network (PSTN); an infra-red network; a wireless network (e.g., a network operating under any of the IEEE 802.11 suite of protocols, the Bluetooth protocol known in the art, and/or any other wireless protocol); and/or any combination of these and/or other networks.

System environment600can also include one or more databases618. In one set of embodiments, database618can include any database or data storage component discussed in the foregoing disclosure, such as storage component104ofFIGS. 1 and 4. Database618can reside in a variety of locations. By way of example, database618can reside on a storage medium local to (and/or resident in) one or more of the computers602,604,606,608,610,612,614. Alternatively, database618may be remote from any or all of computers602,604,606,608,610,612,614and/or in communication (e.g., via network616) with one or more of these. In one set of embodiments, database618can reside in a storage-area network (SAN) familiar to those skilled in the art. Similarly, any necessary files for performing the functions attributed to the computers602,604,606,608,610,612,614can be stored locally on the respective computer and/or remotely on database618, as appropriate. In one set of embodiments, database618is a relational database, such as Oracle10gavailable from Oracle Corporation. In particular embodiment, database618is adapted to store, update, and retrieve data streams in response to SQL-formatted commands.

FIG. 7is a simplified block diagram illustrating physical components of a computer system700that may incorporate an embodiment of the present invention. In various embodiments, computer system700can be used to implement any of the computers602,604,606,608,610,612,614illustrated in system environment600described above. As shown inFIG. 7, computer system700comprises hardware elements that can be electrically coupled via a bus724. The hardware elements can include one or more central processing units (CPUs)702, one or more input devices704(e.g., a mouse, a keyboard, etc.), and one or more output devices706(e.g., a display device, a printer, etc.). Computer system700can also include one or more storage devices708. By way of example, storage device(s)708can include devices such as disk drives, optical storage devices, and solid-state storage devices such as a random access memory (RAM) and/or a read-only memory (ROM), which can be programmable, flash-updateable and/or the like.

Computer system700can additionally include a computer-readable storage media reader712, a communications subsystem714(e.g., a modem, a network card (wireless or wired), an infra-red communication device, etc.), and working memory718, which can include RAM and ROM devices as described above. In some embodiments, computer system700can also include a processing acceleration unit716, which can include a digital signal processor (DSP), a special-purpose processor, and/or the like.

Computer-readable storage media reader712can further be connected to a computer-readable storage medium710, together (and, optionally, in combination with storage device(s)708) comprehensively representing remote, local, fixed, and/or removable storage devices plus storage media for temporarily and/or more permanently containing computer-readable information. Communications system714can permit data to be exchanged with network616ofFIG. 6and/or any other computer described above with respect to system environment600.

Computer system700can also comprise software elements, shown as being currently located within working memory718, including an operating system720and/or other code722, such as an application program (which may be a client application, web browser, web server application, RDBMS, etc.). It should be appreciated that alternative embodiments of computer system700can have numerous variations from that described above. For example, customized hardware can also be used and/or particular elements can be implemented in hardware, software (including portable software, such as applets), or both. Further, connection to other computing devices such as network input/output devices can be employed.

In one set of embodiments, the techniques described herein can be implemented as program code executable by a computer system (such as computer system700) and can be stored on machine-readable storage media. Machine-readable storage media can include any  appropriate media known or used in the art, including storage media and communication media, such as (but not limited to) volatile and non-volatile, removable and non-removable media implemented in any method or technology for storage and/or transmission of information such as machine-readable instructions, data structures, program modules, or other data, including RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disk (DVD) or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to store or transmit the desired information and which can be accessed by a computer.

Although specific embodiments of the present invention have been described, various modifications, alterations, alternative constructions, and equivalents are within the scope of the invention. For example, embodiments of the present invention are not restricted to operation within certain specific environments, but are free to operate within a plurality of environments. Additionally, although embodiments of the present invention have been described using a particular series of transactions and steps, it should be apparent to those skilled in the art that the scope of the present invention is not limited to the described series of transactions and steps.

Further, while embodiments of the present invention have been described using a particular combination of hardware and software, it should be recognized that other combinations of hardware and software are also within the scope of the present invention. Embodiments of the present invention may be implemented only in hardware, or only in software, or using combinations thereof

The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense. The scope of the invention should be determined not with reference to the above description, but instead should be determined with reference to the pending claims along with their full scope or equivalents.