Chapter 11 Advanced NOS Administration

1
Chapter 11 Advanced NOS Administration

• 11.1 Backups
• 11.2 Drive Mapping
• 11.3 Partition and Processes Management
• 11.4 Monitoring Resources
• 11.5 Analyzing and Optimizing Network
  Performance

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Backups
3
Overview of Backup Methods

• The backup process involves copying data from one
  computer to some other reliable storage medium
  for safekeeping.
• Once the data has been archived, the system
  administrator can then restore data to the system
  from any previously recorded backup.
• Considerations that are relevant for storage
  devices
• Cost
• Size
• Manageability
• Reliability

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Overview of Backup Methods

• There are four types of backup procedures that
  define how the backup will take place
• Full - will backup everything on the hard drive
  at the scheduled point in the day
• Partial - backs up selected files
• Incremental - only the files that have changed
  since the last backup will be selected for back
  up
• Differential - backs up files created or changed
  since the last normal or incremental backup

5
Installing Backup Software

• With the release of Windows 2000, the backup
  utility that existed with Windows NT was greatly
  enhanced.
• This Windows NT tool has replaced RDISK, and it
  is now used to back up the Registry.
• It is no longer confined to only tapes as output
  media, and it offers a number of other
  possibilities as well.

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Installing Backup Software

• The Linux OS includes two utilities that can
  perform backups.
• They are tar and cpio. The tar utility, which is
  a tape archiever, combines multiple files into a
  single file that can be copied to the media.
• The cpio utility is used to copy in/out.
• It can perform three basic actions, one of which
  must be specified
• -i To extract from an archive
• -o To make a new archive
• -p To print/pass (through the files)

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Backup Hardware

• The most common backup hardware device used
  before and now is some form of magnetic tape
  drive.
• Tape devices are known for their long-lasting
  performance, which is partly due to the tape
  drive mechanics that some systems include.
• There are a variety of tape devices that use
  different tape formats for storing data.
• Many tape drives can also compress the data
  before it is stored on the tape.
• In most cases the compression ratio is 21.

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Backup Hardware

• Quarter Inch Cartridge (QIC, pronounced quick),
  is a tape standard.
• Travan tape drives have a higher storage capacity
  than the older QIC tape drives. The most recent
  standard implemented on Travan tape drives was
  hardware compression.

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Backup Hardware

• 8mm tape technology uses a tape similar to 8mm
  videotape and the same helical scan system used
  by a VCR.
• Mammoth 8mm tape technologies are an improvement
  on the original 8mm tape technologies with higher
  storage capacities and faster transfer speeds.
• AIT technology uses 8mm tapes that use the
  helical scan recording hardware, which is much
  like a VCR and have memory in the tape cartridge,
  known as Memory-In-Cassette (MIC).

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Backup Hardware

• The Digital Audio Tape (DAT) tape standard uses
  4mm digital audiotapes to store data in the
  Digital Data Storage (DSS) format.
• Digital Linear Tape (DLT) technology offers high
  capacity and relatively high-speed tape backup
  capabilities. DLT tapes record information on the
  tape in a linear format.
• Linear Tape-Open (LTO) technology comes in two
  distinct forms.
• One is designed for high storage capacity
  (Ultrium), and the other is designed for fast
  access (Accelis).

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Backup Strategies

• There are several accepted backup strategies, and
  many of them are based on this popular
  Grandfather-Father-Son (also known as
  Child-Parent-Grandparent) method.
• This backup strategy uses three sets of tapes for
  daily, weekly, and monthly backups.

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Automating Backups

• System backups should be performed at regular
  intervals to provide consistent data protection.
• Automation of such regularly scheduled events is
  an important backup consideration.
• Automation not only increases backup consistency
  but also gives system administrators more time to
  address other important network issues.
• The most common automated backup procedure
  consists of a system administrator inserting a
  tape into the drive at the end of the day.
• The system performs the regularly scheduled
  nightly backup of data onto the tape.
• The system administrator ejects that tape the
  next day and stores it for a predetermined period
  of time.

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Drive Mapping
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What is Drive Mapping?

• Drive mapping is a useful tool that allows an
  administrator to share resources that are stored
  on a server.
• The client computers that are connected to the
  network assign a drive letter that will act as a
  direct path to access those resources stored on a
  server over the network.
• After a user identifies a network resource to be
  used locally, the resource can be "mapped" as a
  drive.

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Mapping Drives in Windows Networks

• To map a drive with Windows Explorer, navigate to
  the folder on the remote system in Windows
  Explorer by selecting Network gt Neighborhood gt
  Server name gt Shared folder name.
• Another way to do this is to choose the Tools
  menu, and then choose Map Network Drive.
• The net use command can be used instead of
  mapping drives through Windows Explorer.
• Net use can also be incorporated into a login
  script that automatically runs when the user logs
  in to the network.

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Mapping Drives in Linux Networks

• A client computer running Linux must be mapped in
  a slightly different way.
• Use the mount command to establish a connection
  to the shared directory on the server.
• Entering the syntax will map a drive to a
  Linux/UNIX share.
• The local directory designation that points to
  the remote share denoted by the first part of the
  command is called the directory mount point.
• The mount point location must already exist
  before a share can be mapped to it.

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Mapping Drives in Novell Networks

• Mapping a drive to a share on a NetWare server
  can be done using Windows Explorer.
• If the NetWare client machines are running
  Windows 95, 98, NT, 2000, or XP, follow the same
  process for mapping drives on a Microsoft
  network.
• A drive can be mapped at the command line by
  using the map command.
• This map command can also be put in a login
  script that executes automatically as the user
  logs into the network.

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Partition and Processes Management
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Using fdisk, mkfs, and fsck

• fdisk is a text-based and requires the use of
  one-letter commands to manipulate the options.
• type m or ? at the fdisk prompt to obtain a list
  of the commands that can be used.
• Once the partition changes have been made, a
  filesystem must be created on the partition.
• This is also referred to as formatting the
  partition.
• Use the mkfs utility to create a filesystem in
  Linux.

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Using fdisk, mkfs, and fsck

• The fsck utility is used to check file systems
  for errors, which occur more frequently than the
  need to add, remove, or format partitions.
• It is a good idea to use this utility often to
  check for file system integrity.

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Managing System Processes with cron Jobs

• The way to schedule tasks to run at regular
  intervals on a Linux system is with Cron
  Programs.
• Also known as Cron jobs, they schedule system
  maintenance tasks that are performed
  automatically.
• System Cron jobs are controls via the
  /etc/crontab file.
• The file begins with set of environmental
  variables. These set certain parameters for the
  Cron jobs such as the PATH and MAILTO
• The other lines in this file, specify the minute,
  hour, day, month, and day of the week the job
  will run.

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Core Dumps

• Core Dump is a recording of the memory that a
  program was using at the time it crashed.
• The purpose of Core Dumps is to allow programmers
  to study the file to figure out exactly what
  caused the program to crash.
• The processes that are currently running on a
  Linux system can be viewed by using the ps
  command.

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Core Dumps

• The ps command has a variety of options that can
  be used with the command to manipulate its
  output.
• These options can be used together to display the
  output wanted using the ps command.
• There can be some considerable output that is
  generated when the command such as ps-A forest
  command.

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Core Dumps

• The top command functions much like the Windows
  2000 Performance tool by providing detailed
  information regarding CPU and RAM usage.
• Sometimes a process will cause the system to lock
  up.
• The kill command can be used to terminate the
  process.
• The signal option represents the specified signal
  that is sent to the process.
• There are 63 different parameters that can be
  entered for the signal that is sent to the
  process.

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Assigning Permissions for Processes

• Typically, programs have the same types of
  permission and can read the same files as the
  user who runs that program.
• There are certain programs that require
  additional permission to be run by certain users.
• Regular users cannot execute the su command,
  because it requires root account privileges.
• Programs such as these are run using the SUID or
  SGID bit, which allows these programs to be run
  under the permission of another user.

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Monitoring Resources
27
Disk Management

• By regularly using error-checking and
  defragmentation programs and continually managing
  free disk space, the system administrator can
  maintain a healthy hard drives.
• One preventive disk management tool available to
  system administrators is the use of "quotas" for
  user accounts.
• A quota acts as a storage ceiling that limits the
  amount of data each user can store on the network.

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Memory Usage

• Memory diagnostic tools that allow RAM intensive
  applications to be discovered, and stopped if
  necessary, are typically built into most NOS
  platforms.
• System administrators can compensate for the lack
  of memory through the use of "virtual memory".
• Virtual memory allocates space on the hard drive
  and treats it as an extension of the system RAM.

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CPU Usage

• All information used by the NOS, including the
  NOS itself, is processed millions of times per
  second by the CPU to display this information to
  the user.
• Built-in tools are commonly provided to allow
  system administrators to monitor the current
  level of CPU activity.
• This feedback is often presented in terms of the
  percentage of the CPU currently being used and is
  refreshed at frequent intervals.

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Reviewing Daily Logs

• Most computer programs, servers, login processes,
  as well as the system kernel, record summaries of
  their activities in log files.
• These summaries can be used and reviewed for
  various things, including software that might be
  malfunctioning or attempts to break into the
  system.
• In Windows 2000, the Computer Management tool
  allows users to browse the logged events
  generated by the NOS.

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Reviewing Daily Logs

• Linux uses log daemons to control the events that
  are entered in the system log.
• Most of the Linux systems log files are located
  in the /var/log directory.
• The log files that are located in this directory
  maintained by the system log daemon (Syslogd) and
  the kernel log daemon (klogd).
• These two daemons are configured using the
  syslog.conf file.

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Checking Resource Usage on Windows 2000 and
Windows XP

• System resources are monitored in Windows 2000
  and Windows XP with the Performance tool.
• This application is found under the Start menu gt
  Programs gt System Administration gt Performance
  menu option.
• Users can then right-click on the graph and
  select Add Counters to specify which system
  resources to monitor in the graph.

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Checking Resource Usage on Linux

• The df command is used to display the amount of
  disk space currently available to the various
  filesystems on the machine.
• When a directory name is specified, the du
  command returns the disk usage for both the
  contents of the directory and the contents of any
  subdirectories beneath it.
• The top command functions much like the Windows
  2000 Performance tool by providing detailed
  information regarding CPU and RAM usage.

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Analyzing and Optimizing Network Performance
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Key Concepts in Analyzing and Optimizing Network
Performance

• The network administrator should make time to
  devise a proactive plan for managing the network.
  
• This plan enables the detection of small problems
  before they become large ones.
• The three key concepts in analyzing and
  optimizing network performance include
• Bottlenecks
• Baselines
• Best practices

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Bottleneck

• It is the point in the system that limits the
  data throughput, which is the amount of data that
  can flow through the network.
• The primary performance-monitoring tool for
  Microsofts Windows 2000 Server is called
  Performance.
• Performance can monitor nearly all hardware and
  software components on a Windows 2000 server.

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Bottleneck

• The various versions of the UNIX/Linux operating
  systems have command-line utilities that can be
  used to monitor performance of the UNIX/Linux
  network server.
• The primary tools are sar, vmstat, iostat, and
  ps.
• The flags used by these commands can vary among
  the different versions of UNIX/Linux.
• Use the UNIX/Linux man command to get specifics
  about the use of these commands.
• The information displayed by the man command also
  tells how to interpret the output generated by
  the command.

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Baselines

• The baseline measurements should include the
  following statistics
• Processor, Memory, Disk subsystem, Network -
  Network queue length
• Determine how efficiently a network is performing
  by comparing various measurements to the same
  measurements taken at an earlier time.
• This point of comparison is called a baseline,
  which is the level of performance that is
  acceptable when the system is handling a typical
  workload.

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Determining Internet Connection Speed

• The speed of a connection is limited by its
  lowest-speed component or the bottleneck.
• This means that even if the equipment is capable
  of a 50-kbps connection, the connection will be
  at the slower speed if the remote modem supports
  only 33.6-kbps.

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Network Monitoring Software

• The network monitor that comes with Windows NT
  and Windows 2000 is a functional and useful tool
  for performing routine protocol analysis.
• Network Monitor can be used to display the
  individual frames of captured data.
• The figure shows that packets for several
  different protocols have been captured, including
  TCP, UDP, and SMB.

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Network Monitoring Software

• The Sniffer products enable sophisticated
  filtering based on pattern matches, IP/IPX
  addresses, and so on.
• Sniffer Pro includes a traffic generator to
  assist in testing new devices or applications.
• It can be used to simulate network traffic or to
  measure response times and hop counts.
• Sniffer uses a dashboard-style interface.

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Network Management Software

• Microsoft SMS is a high-end network management
  package that provides hardware and software
  inventory by installing the client agent on
  target computers.
• One of the most useful features of SMS is its
  software distribution feature.
• The distribution package contains the information
  used by SMS to coordinate the distribution of the
  software.

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Network Management Software

• ManageWise includes an alarm/notification
  feature, NetWare LANalyzer agent, the management
  agent, Intel LANDesk Manager, Desktop Manager,
  and LANDesk virus protection.
• Tivoli is capable of providing a complete view of
  the network topology.
• Reporting tools enable customization of the view
  in which the data is presented, and "smart sets"
  can be created that group data logically.

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Management Software for Small and Medium-Sized
Networks

• SNMP is a protocol that is included in most
  implementations of TCP/IP. It has several
  advantages
• Simplicity, Low cost, Relative ease of
  implementation, Low overhead on the network,
  Supported by most network hardware devices
• It uses a hierarchical database called a
  Management Information Base (MIB) to organize the
  information it gathers about the network.

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Management Software for Small and Medium-Sized
Networks

• CMIP was designed to improve on SNMP and expand
  its functionality.
• It works in much the same way as SNMP, but it has
  better security features.
• Also, it enables notification when specified
  events occur.
• Since the overhead for CMIP is considerably
  greater than that which is required for SNMP, it
  is less widely implemented.
• CMIP is based on the OSI protocol suite.

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Management Service Provider (MSP)

• A new development in network management is the
  Management Service Provider (MSP).
• A company subscribes to an MSP service, which
  provides performance monitoring and network
  management.
• This saves the organization the cost of buying,
  installing, and learning to use monitoring and
  management software.

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SNMP Concepts and Components

• There are two main parts to SNMP
• Management side The management station is the
  centralized location from which users can manage
  SNMP.
• Agent The agent station is the piece of
  equipment from which issuers are trying to
  extract data.
• At least one management system is needed to even
  be able to use the SNMP Service.
• Certain commands can be issued specifically at
  the management system.

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SNMP Concepts and Components

• The SNMP agent is responsible for complying with
  the requests and responding to the SNMP manager
  accordingly.
• Generally, the agent is a router, server, or hub.
  
• The agent is usually a passive component only
  responding to a direct query.
• In one particular instance, however, the agent is
  the initiator, acting on its own without a direct
  query.
• This special case is called a trap.
• A trap is set up from the management side on the
  agent.

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SNMP Structure and Functions

• The data that the management system requests from
  an agent is contained in a Management Information
  Base (MIB).
• The namespace for MIB objects is hierarchical.
• It is structured in this manner so that each
  manageable object can be assigned a globally
  unique name.
• After the SNMP agent is installed, it must be
  configured with an SNMP community name.
• The default SNMP community name is Public.

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SNMP Structure and Functions

• These three steps show what SNMP is really doing
• A community is a group of hosts running the SNMP
  Service to which they all belong.
• There really is no established security with
  SNMP. The data is not encrypted.
• Notification is possible using SNMP and will vary
  on an operating systembyoperating system basis.