Abstract:
A method and system is described for monitoring the performance of a monitored server system using a polling server system. A single query is generated by the polling server system and transmitted to the monitored server system. The single query represents a request for a compilation of information about the performance of numerous services offered by a monitored server system. Upon receiving the single query, the monitored server system generates the compilation of information regarding the services it offers, and then transmits the compilation of information to the polling server system.

Description:
RELATED APPLICATION 
   This application is a continuation of U.S. application Ser. No. 09/353,304 entitled “System and Method for Monitoring Server Performance Using a Server” filed Jul. 13, 1999, now abandoned which is a continuation-in-part of U.S. application Ser. No. 08/682,832 entitled “System and Method for Monitoring Server Performance at a Client Computer” (as amended), filed Jul. 12, 1996, now U.S. Pat. No. 5,938,729, which is incorporated herein by reference in its entirety. 

   BACKGROUND OF THE INVENTION 
   1. The Field of the Invention 
   The present invention relates to electronic communications. Specifically, the present invention relates to a system and method for monitoring server performance using a server. 
   2. The Prior State of the Art 
   Computer networks are playing an increasingly important role in the information age. One important component of a computer network is a server system. A “server system” is a hardware and/or software component that provides services to another component of the computer network typically termed a “client system.” The client system may be, for example, a personal computer or workstation associated with a user. 
   A typical server system may provide numerous services to a client system. These services might be available, for example, in the form of software modules. The server software is supported by operating system software that provides the server software with access to resources such as the server&#39;s computer hardware resources and the server&#39;s user interface resources. 
   It is desirable to monitor the performance of server systems on a network to ensure the network is operating properly. Typically, the operating status of an individual service of a server system may be determined by sending a computer-generated query to the server system. In response to the query, the server system sends a reply that includes the operating status of the service. The reply indicates, among other things, whether the service is running. The queries and replies typically include at least one query and one reply per service. Thus, to determine the status of multiple services at a single server, the querying computer sends multiple queries and receives multiple replies. 
   The issuance of each query takes time. Thus, it is desirable to reduce the number of queries generated to monitor the performance of the services provided by a server system. 
   SUMMARY OF THE INVENTION 
   The present invention relates to a method and system for monitoring the performance of a monitored server system using a polling server system. However, the number of queries needed to be issued for each monitored server system is significantly reduced, thereby significantly reducing polling time 
   Instead of a query being generated and transmitted for each service offered by a monitored server system, a single query is generated for the entire monitored server system. Specifically, the single query is generated by a polling server system. The single query represents a request for a compilation of information about the performance of numerous services offered by the monitored server system. After generating the single query, the polling server system then transmits this single query to the monitored server system. Upon receiving the single query, the monitored server system generates the compilation of information regarding the services it offers, and then transmits the compilation of information to the polling server system. Thus, with this single query, the polling server system obtains an entire compilation of information regarding the performance of the monitored server system. The polling server can likewise query other monitored server systems to obtain further compilations. 
   The compilation of information may include performance deficiencies detected in the monitored server system. When a deficiency is detected in the most recent polling of the monitored server system, the monitored server system is listed in a critical server system list. At this point, the polling server system may poll the critical server system more frequently since the monitoring of the server system performance is typically more important once an operating deficiency is detected. 
   Once the compilation of information is obtained by the polling server system, any or all of the compilation may be then provided to a client system so that, for example, a system administrator can review the information to diagnose and remedy any deficiency in the monitored server system. The compilation may be provided to the client system either automatically, or upon the happening of a predetermined event such as receiving a request for the compilation from the client system. 
   Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instruments and combinations particularly pointed out in the appended claims. These and other objects and features of the present invention will become more fully apparent from the following description and appended claims, or may be learned by the practice of the invention as set forth hereinafter. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In order that the manner in which the above-recited and other advantages and objects of the invention are obtained, a more particular description of the invention briefly described above will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. Understanding that these drawings depict only typical embodiments of the invention and are not therefore to be considered limiting of its scope, the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings in which: 
       FIG. 1  illustrates an exemplary system that provides a suitable operating environment for the present invention; 
       FIG. 2  is a schematic diagram illustrating a suitable network environment in which the invention can be implemented; 
       FIG. 3  is a flowchart of a method for polling monitored server systems for information; 
       FIG. 4  is a block diagram of a client-server system in the network environment of  FIG. 2 ; 
       FIG. 5  is a flowchart of a method for the login and mail-reading capabilities of the monitored server system; 
       FIG. 6  is a flowchart of a method for testing the buffer-service-updating capability of the monitored server system; 
       FIG. 7  is a block diagram of the structure of a compilation reply; 
       FIG. 8  is a flowchart of a procedure for including the status of a software service in the compilation reply of  FIG. 7 ; and 
       FIG. 9  is a flowchart of a procedure for synchronizing a monitored server system time indicator with a master time indicator. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   The present invention relates to systems and methods for monitoring server system performance using a server system. Specifically, a polling server system generates a single request to obtain a compilation of information from a monitored server system. Since fewer queries are needed to monitor each server system, polling time is reduced and network efficiency improved. 
   Embodiments within the scope of the present invention include computer-readable media having computer-executable instructions or data structures stored thereon. Such computer-readable media can be any available media which can be accessed by a general purpose or special purpose computer. By way of example, and not limitation, such computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to store the desired computer-executable instructions or data structures and which can be accessed by a general purpose or special purpose computer. When information is transferred or provided over a network or another communications connection to a computer, the computer properly views the connection as a computer-readable medium. Thus, such a connection is also properly termed a computer-readable medium. Combinations of the above should also be included within the scope of computer-readable media. Computer-executable instructions comprise, for example, instructions and data which cause a general purpose computer, special purpose computer, or special purpose processing device to perform a certain function or group of functions. 
     FIG. 1  and the following discussion are intended to provide a brief, general description of a suitable network environment in which the invention may be implemented. Although not required, the invention will be described in the general context of computer-executable instructions, such as program modules, being executed by computers in network environments. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types. Computer-executable instructions, associated data structures, and program modules represent examples of the program code means for executing steps and acts of the methods disclosed herein. 
   Those skilled in the art will appreciate that the invention may be practiced in network computing environments with many types of computer system configurations, including personal computers, hand-held devices, multi-processor systems, microprocessor-based or programmable consumer electronics, network PCs, minicomputers, mainframe computers, and the like. The invention may also be practiced in distributed computing environments where tasks are performed by local and remote processing devices that are linked through a communications network. In a distributed computing environment, program modules may be located in both local and remote memory storage devices. 
   With reference to  FIG. 1 , an exemplary system for implementing the invention includes a general purpose computing device in the form of a computer  20 , including a processing unit  21 , a system memory  22 , and a system bus  23  that couples various system components including the system memory  22  to the processing unit  21 . The system bus  23  may be any of several types of bus structures including a memory bus or memory controller, a peripheral bus, and a local bus using any of a variety of bus architectures. The system memory includes read only memory (ROM)  24  and random access memory (RAM)  25 . A basic input/output system (BIOS)  26 , containing the basic routines that help transfer information between elements within the computer  20 , such as during start-up, may be stored in ROM  24 . 
   The computer  20  may also include a magnetic hard disk drive  27  for reading from and writing to a magnetic hard disk, not shown, a magnetic disk drive  28  for reading from or writing to a removable magnetic disk  29 , and an optical disk drive  30  for reading from or writing to removable optical disk  31  such as a CD-ROM or other optical media. The magnetic hard disk drive  27 , magnetic disk drive  28 , and optical disk drive  30  are connected to the system bus  23  by a hard disk drive interface  32 , a magnetic disk drive-interface  33 , and an optical drive interface  34 , respectively. The drives and their associated computer-readable media provide nonvolatile storage of computer-executable instructions, data structures, program modules and other data for the computer  20 . Although the exemplary environment described herein employs a magnetic hard disk, a removable magnetic disk  29  and a removable optical disk  31 , other types of computer readable media for storing data can be used, including magnetic cassettes, flash memory cards, digital video disks, Bernoulli cartridges, RAMs, ROMs, and the like. 
   A number of program modules may be stored on the hard disk, magnetic disk  29 , optical disk  31 , ROM  24  or RAM  25 , including an operating system  35 , one or more application programs  36 , other program modules  37 , and program data  38 . A user may enter commands and information into the computer  20  through keyboard  40 , pointing device  42 , or other input devices (not shown), such as a microphone, joy stick, game pad, satellite dish, scanner, or the like. These and other input devices are often connected to the processing unit  21  through a serial port interface  46  coupled to system bus  23 . Alternatively, the input devices may be connected by other interfaces, such as a parallel port, a game port or a universal serial bus (USB). A monitor  47  or another display device is also connected to system bus  23  via an interface, such as video adapter  48 . In addition to the monitor, personal computers typically include other peripheral output devices (not shown), such as speakers and printers. 
   The computer  20  may operate in a networked environment using logical connections to one or more remote computers, such as a remote computer  49 . Remote computer  49  may be another personal computer, a server, a router, a network PC, a peer device or other common network node, and typically includes many or all of the elements described above relative to the computer  20 , although only a memory storage device  50  has been illustrated in  FIG. 1 . The logical connections depicted in  FIG. 1  include a local area network (LAN)  51  and a wide area network (WAN)  52  that are presented here by way of example and not limitation. Such networking environments are commonplace in office-wide or enterprise-wide computer networks, intranets and the Internet. 
   When used in a LAN networking environment, the computer  20  is connected to the local network  51  through a network interface or adapter  53 . When used in a WAN networking environment, the computer  20  typically includes a modem  54  or other means for establishing communications over the wide area network  52 , such as the Internet. The modem  54 , which may be internal or external, is connected to the system bus  23  via the serial port interface  46 . In a networked environment, program modules depicted relative to the computer  20 , or portions thereof, may be stored in the remote memory storage device. It will be appreciated that the network connections shown are exemplary and other means of establishing a communications link between the computers may be used. 
     FIG. 2  illustrates a client-server system  210  that includes server systems  212  that are networked together and with client systems  214 . Client software  216  resides on the client systems  214  and server software  218 , including various services  226 , resides on the server systems  212 . Each server system  212  also may include a time indicator  220  that is used by the server software  218  for adding a timestamp to outgoing messages. 
   In one embodiment, client-server system  210  is a messaging system, server systems  212  are messaging servers, client systems  214  are user computers such as the computer  20  of  FIG. 1 , client software  216  is client messaging software, and server software  218  is server messaging software. Although this embodiment of a messaging system is described in further detailed below, it will be understood that the principles of the present invention may extend to many other types of network systems as well. 
   In the case of a messaging system, the client messaging software  216  and the server messaging software  218  allow the user associated with each client system  214  to create outgoing messages and otherwise manipulate messages. In addition, in order to read messages stored at the user&#39;s mailbox at the corresponding server system  212 , the user&#39;s client system  214  links with the corresponding server system  212  by, for example, initiating a messaging session. 
   To initiate a messaging session, the user runs the client messaging software  216  and causes the client messaging software  216  to log into the server system  212  using a login procedure. Typically, a user password is passed to the server messaging software  218 , which allows a working connection to be established only if the server system  212  recognizes the password. After the login procedure is completed, the user is able to proceed with the messaging session. The messaging session may be closed and the working connection may be broken by the user de-activating the client messaging software  216 . Deficiencies in the client-server system  210  are detected by a monitoring system that includes polling software  224  that resides on one of the server systems  212  that polls (namely, polling server system  212 ″) and attendant software  222  that resides on the server systems  212  that are monitored (namely, monitored server systems  212 ′). Each instance of attendant software  222  compiles information about the server system  212  on which the attendant software  222  runs and, when queried by the polling software  224 , provides the compilation to the polling software  224 . 
   The compilation includes information about the services  226  of the server messaging software  218  including, for example, a directory service, a message store service, and a message transfer agent service. The directory service maintains records of locations of mailboxes in the messaging system and is used in the delivery of a message. The message store service stores and retrieves incoming messages for reading and other manipulation by users associated with the server. The message transfer agent service consults the directory service to deliver messages in the messaging system. 
   The polling software  224  maintains two lists of server systems to query: a normal server system list and a critical server system list. The critical server system list includes all server systems that the polling software  224  has discovered as having deficiencies. The normal server system list includes all the other monitored server systems. Initially, all of the server systems monitored by the polling software  224  are included in the normal server system list since the server systems are assumed to have no deficiencies unless a deficiency is discovered. As described below, a server system entry may be transferred from the normal server system list to the critical server system list if a deficiency is discovered at the server system. 
   The server systems in the normal server system list are queried by the polling software  224  in accordance with a “normal” polling interval such as, for example, 15 minutes. The server systems in the critical server system list are queries at more frequent intervals of, for example, 2 minutes. 
     FIG. 3  is a diagram of a polling procedure that is triggered in response to the commencement of one of the above-described polling intervals. The polling software  224  first determines the server systems to query by referring to the appropriate server systems list as is now described. If the procedure was triggered in accordance with the critical polling interval (Yes in decision block  300 ), the polling software  224  refers to the critical server system list (step  310 ). Otherwise (No in decision block  300 ), the polling software  224  refers to the normal server system list (step  320 ). 
   The polling software  224  then performs the following method for each server system in the resulting list. First, the polling software  224  queries the server system (step  330 ) by, for example, sending a network message to the attendant software  222  associated with the monitored server system. The attendant software  222  is expected to reply to the query with information in a compilation. The reply includes status indicators that indicate whether deficiencies exist in the time indicator  220  or services  226  of the server system. If the attendant software  222  for the server system does not reply with a compilation of information (No in decision block  340 ), the polling software  224  determines that the attendant software  222  is not operating properly, which constitutes a deficiency. The non-responsive server system is then listed in the critical server system list (step  360 ). 
   If the attendant software  222  or the monitored server system does reply with a compilation of information (Yes in decision block  340 ), the polling software  224  determines if there are any deficiencies in the server system as indicated in the reply (decision block  350 ). If a deficiency is found (Yes in decision block  350 ), the server system is listed in the critical server system list (step  360 ). On the other hand, if there are no deficiencies found (No in decision block  350 ), the server system is listed in the normal server system list (step  370 ). This process is repeated for all server systems in the list generated by steps  300 ,  310  and  320 . 
   For example, in the context of a messaging system, an administrator may configure the polling software  224  to transfer the list entry for the server system to the critical server system list if the polling software  224  discovers that the site&#39;s directory service is in a non-functioning state (step  360 ). Such a transfer is appropriate, because the monitored server system is unable to operate properly without a functioning directory service. Transferring the list entry for the deficient server system to the critical server system list allows the polling software  224  to provide an administrator with information about the deficient server system more frequently. 
   The administrator is also able to pre-select configuration settings for the polling software  224  for queries involving the critical server system list. For example, according to a list-transfer setting, a list entry for a server system may be transferred back to the normal server system list (step  370 ). Such a transfer may occur if all deficiencies reflected in earlier replies from the server system&#39;s attendant software are absent from the most recent reply from that attendant software. In most cases, such a setting is appropriate, because, after all of a server system&#39;s deficiencies have cleared, the administrator typically desires information at less frequent intervals. A deficiency may clear in response to one or more actions taken by the administrator or by an automated mechanism or both. 
   At the monitored server system  212 ′, the attendant software  222  preferably may gather some information autonomously and other information only after receiving a query from the polling software  224 . However, all of the information provided in response to the query, regardless of the way in which some of the information is gathered, is provided to the polling software  224  in one compilation and is not provided piecemeal. For example, the attendant software  222  autonomously monitors a particular capability of the server messaging software  218 . The capability involves allowing the reading of mail and making a working connection with a new instance of client messaging software  216 , as described above. The attendant software  222  so monitors by simulating the executions of a mail-reading procedure and a login procedure. The simulation is accomplished by exercising the server messaging software  218  in the same way that the server messaging software  218  is exercised in the executions of actual mail-reading and login procedures. 
     FIG. 4  illustrates the operation of the server messaging software  218 . The system attendant software  222  has a messaging account, i.e., the attendant account, that is created when the attendant software  222  is first located and started at the server system  212 . The use of the attendant account differs from the use of the messaging account of an ordinary user of the server system  212  in that the attendant software  222  does not send a password to gain access to the attendant account. Instead, the attendant software  222  gains access by submitting security codes retrieved from a network source that is responsible for network security. In other regards, the attendant account is preferable identical, aside from its contents and the like, to an ordinary user&#39;s account. 
   At the time the attendant account is created, a message store buffer service  240  is also located and started at the server system  212 . Through the buffer service  240 , the attendant software  240  gains access to the server software&#39;s message store service  242 . The buffer service  240  is preferably identical to a user buffer service  244  that, in the case of an actual user, runs on the user&#39;s client system  214  along with the user messaging software  216 . With respect to an actual user, the user buffer service  244  minimizes the user software&#39;s use of the link between the user software and server software by buffering information from the message store service  242 . For example, when the message store service  242  receives a new message directed to the user running the client messaging software  216 , the message store service  242  sends a new-mail indication to the user buffer service  240 . Thus, when the client messaging software  216  is ready to determine whether the user has one or more new messages, the user software is able to make the determination by referring to the user buffer service  240 , not to the message store service  242  directly. 
   The attendant software  222  tests the use of the buffer service  240  by executing, at periodic intervals “A” of preferably one minute each, an interval A function as shown in  FIG. 5 . First, the attendant software  222  determines whether it is necessary for the attendant software  222  to execute a login procedure to establish a working connection with the server software (decision block  400 ). If so, a login procedure is attempted (step  405 ). In the login procedure, the server software restarts services and establishes a working connection with the attendant software  222 . If the login procedure fails ( 410 ), the attendant software  222  reports a login failure (step  415 ) for the next compilation reply, as described below, and terminates the execution of the interval A function. On the other hand, if the login procedure is successful, the attendant software  222  reports a login success (step  420 ) and the execution of the interval A function continues. 
   A working connection having been established during this or a previous instance of executing an interval A function, the attendant software  222  then requests that the buffer service  240  indicate whether any new messages have arrived for the attendant software  222  (step  425 ). If the buffer service  240  responds properly to the request (Yes in decision block  430 ), the attendant software  222  then determines whether the response of the buffer service  240  indicates that the attendant software  222  has a new message (step  435 ). If the response so indicates (Yes in decision block  435 ), the attendant software  222  then attempts to read the new message (step  440 ). A successful read attempt or a lack of a new message to read causes the attendant software  222  to finish the interval A function with a successful report (step  445 ). 
   However, if the attendant software  222  does not receive a proper response from the buffer service  240  or if the read attempt is unsuccessful, the attendant software  222  reports failure (step  450 ) and then executes a logoff procedure (step  455 ). In the logoff procedure, the attendant software  222  terminates the working connection with the server software. The logoff procedure is executed to set up the attendant software  222  to attempt to execute a login procedure at the start of the next execution of an interval A function. The logoff-login sequence is used to (1) attempt to address the cause of the failure, by causing, as described above, services to restart in the login procedure, and (2) test the ability of the server software to accept the execution of a login procedure. 
   In the case of an actual user and user computer, the buffer service  240  rarely requests information from the message store service  242 . Rather, the buffer service  240  simply waits for the message store service  242  to provide information. However, the buffer service  240  includes a facility that is triggered when the buffer service  240  has not received information from the message store service for a long time, e.g., one hour, while a working connection exists. The facility is triggered to confirm that the lack of received information is not due to a problem in communications between the buffer service  240  and the message store service  242 . The facility updates the buffer service&#39;s buffer of information by causing the buffer service to renew the buffer service&#39;s connection with the message store service and to request information from the message store service. 
   The attendant software  222  uses the facility at intervals “B”, preferably every five minutes. The use of the facility at every five minutes allows the attendant software  222  to detect a communications problem quickly, i.e., within much less than the facility&#39;s standard one-hour interval. In the interval B function of  FIG. 6 , the attendant software  222  is able to use the facility only if the attendant software  222  has a working connection to the server software, i.e., if the attendant software  222  is “logged in” (Yes in decision block  500 ). The attendant software  222  invokes the facility (step  510 ) and then determines whether the invocation was successful (step  520 ). The invocation is expected to be successful unless the buffer service  240  has developed a problem. 
   If successfully invoked, the facility then requests an update, as described above, from the message store service  242  (step  530 ). If the update proceeds successfully (Yes in decision block  540 ), the success is reported for the next compilation reply (step  550 ). However, if either the invocation or the update request is unsuccessful, the attendant software  222  reports failure for the interval B function (step  560 ). 
   The reports of the interval A and interval B function are included in the compilation reply that is sent to the polling software  224  after the attendant software  222  receives a query from the polling software  224 .  FIG. 7  illustrates the construction of the compilation reply  258 . The interval A and interval B functions  260 ,  262  contribute reports  264 ,  266  about the last attempt of the attendant software  222  to read mail and update the buffer service  240 . In addition, a report  268  about the attendant software&#39;s login-related capability is included from the login test  270  that is driven via the interval A function  260 . The compilation reply  258  also includes a time value  272  from the server&#39;s time indicator  220 . The compilation reply  258  further includes, from a service-status function  276  of the attendant software  222 , a set  278  of reports that includes the status of each of various services running on the server. 
   To include each status in the reply  258 , the attendant software  222  first determines the services for which a status should be reported as shown in  FIG. 8  (step  700 ). The attendant software  222  so determines by referring to a services list that includes services that were pre-selected by the administrator for the particular server. The server&#39;s services list preferably includes server messaging software services such as, as noted above, the directory service, the message store service, and the MTA service. Depending on the services available on a particular server, the administrator can configure the server&#39;s services list to include other services as well. Examples of these other services are (1) a service that is involved with communicating messages and computer data across the Internet and (2) a facsimile communications service. 
   The attendant software  222  then determines, for each service in the service list, whether the service is functioning properly (step  710 ). To do so, the attendant software  222  preferably invokes a facility of the operating system that reports whether the service is functioning properly. The report of the facility serves as the basis of the status determined for the service. 
   Finally, for each service in the services list, the attendant software  222  adds the status of the service to the reply  258  (step  720 ). When the polling software  224  receives a compilation reply  258  from a server, the polling software  224  updates the server&#39;s clock  120  if necessary as shown in  FIG. 9 . To do so, the polling software  224  first retrieves the server&#39;s time from the reply  258  (step  800 ). The time includes a time zone indicator. The server&#39;s time is adjusted with respect to time zone and then compared to a master time kept by a master time indicator at the polling software&#39;s user computer (step  810 ). The difference in the times is then compared to a maximum permissible difference that is pre-selected by the administrator (step  820 ). If the maximum permissible difference is exceeded, the polling software  224  then causes the server&#39;s time indicator  220  to be updated to match the user&#39;s computer&#39;s master time indicator (step  830 ). By updating each server&#39;s clock as just described, the polling software  224  is able to synchronize the clocks of all of the messaging system&#39;s servers  212  that share the polling software  224 . 
   The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.