maintaining the network

17Maintaining the Network

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Monitoring the Network Network systems need to be constantly monitored

to: Determine when failures occur To predict possible or imminent failure

Activity can be monitored, recorded, and expressed statistically to predict failure

Predictions are based on system history


Baseline Should be established immediately after the

network or server is installed Should be routinely collected and reviewed to

predict events that could affect network or server performance


Network Baseline Information Peak utilization—Should not exceed 80% Average utilization—Should not exceed 40% Frame size peak and frame size average—Size

affected by protocol and equipment used, amount of segment traffic, and type of data transmitted

Number of protocols—Large number can indicate an improperly configured network device


Network Baseline Information (Cont.)

Number of nodes—Number of nodes communicating on the network segment

Most active 10 nodes—Indicator of possible network problem locations

Collisions—Primary indicator of a problem Packets dropped—Good indication there is a

cable or connection problem


Traffic Shaping Techniques Routers or layer 3 switches can be installed to

provide additional segment links Multiple segment paths can increase network

reliability provided by link redundancy


Network Bottlenecks Can be caused by servers and devices Insufficient resources

Solution: Add more RAM or configure more hard disk drives and map users to additional drives

Unbalanced client loads Solution: Change default server logon for users

Incorrectly configured service(s)


Server Baseline Memory utilization and swap file activity—

Determine if more RAM needs to be installed Hard disk activity—Determines if additional hard

drives need to be installed CPU utilization—Should not exceed 85%


Performance Monitor Provides administrator with information needed

for making objective decisions about the system Can be configured to send alerts to the

administrator when resources are critical Can be used to predict system failure or to isolate

cause of the poor performance


Performance Monitor Display


Windows Task Manager Provides a quick view of system performance Can show what software applications, processes,

and services are running


Resource Monitor


Microsoft Network Monitor Can be used to establish a baseline Displays all active network connections Collects frames in similar manner to protocol

analyzers Filters can be applied to specific protocol types or

contents Identifies fewer protocols than network analyzer


Microsoft Network Monitor Display


Event Viewer Records events that occur on computer, such as:

Starting and stopping of a service User logon activities Share access File access Hardware and software information

Excellent utility for troubleshooting system failures


Event Viewer Display


Maintaining System IntegrityTo protect data, fault tolerance and disaster recovery must be designed into the networkFault tolerance includes some RAID systems and electrical power systemsDisaster recovery includes data backups; hot and cold spares; and hot, warm, and cold sites


RAID 1RAID 1 consists of two disk drives with matching data on each drive


RAID 5RAID 5 combines parity and stripingAt least three hard disk drives are needed for a RAID 5 configuration


Backup Data MethodsFull backup—Only data needs to be copiedArchive bit is set on files when a full or incremental backup is performedArchive bit is not reset when a differential backup is performed or when copy and xcopy commands are used


Incremental BackupLess time than full backupFull backup is performed first, followed by daily incremental backupsTo restore, full backup is restored first, followed by daily incremental backupsIncremental backups must be restored in sequence


Differential BackupPerformed on days when full backup is not being performedPerform a full backup first, followed by daily differential backupsTo restore, full backup is restored first, then the last differential backup


Storing Backup DataStore data backups

Off-site In a secure area with limited access In a climate-controlled storage area

Avoid storing backups In direct sunlight Near electrical panels or in equipment rooms Near magnetic fields generated by electrical

equipment

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