Section 12: Maintaining Section 12: Maintaining the Networkthe Network

CSIS 479R Fall 1999CSIS 479R Fall 1999

““Network +”Network +”

George D. Hickman, CNI, CNEGeorge D. Hickman, CNI, CNE

ObjectivesObjectives

• Choose a backup strategyChoose a backup strategy• Describe strategies for anti-virus Describe strategies for anti-virus

protectionprotection• Describe uninterruptible power supplies Describe uninterruptible power supplies

(UPSs)(UPSs)• Explain RAID and define each class of its Explain RAID and define each class of its

levelslevels• Use patches to maintain workstations Use patches to maintain workstations

and serversand servers• Describe disaster recovery optionsDescribe disaster recovery options

Backup StrategiesBackup Strategies

• FullFull– All data, regardless of when or if it has been All data, regardless of when or if it has been

previously backed uppreviously backed up– Archive Bit = clearedArchive Bit = cleared

• IncrementalIncremental– Files created/changed since last full or Files created/changed since last full or

incremental backupincremental backup– Archive Bit = ClearedArchive Bit = Cleared

• DifferentialDifferential– All data different from last full backupAll data different from last full backup– Archive Bit = Not ClearedArchive Bit = Not Cleared

Strategies (Con’t)Strategies (Con’t)

• Full backup each sessionFull backup each session– Requires the most time to backupRequires the most time to backup– Requires the least time to restoreRequires the least time to restore

• Full backup with incrementalFull backup with incremental– Requires the least time to backupRequires the least time to backup– Requires the most time to restoreRequires the most time to restore

• Full backup with differentialFull backup with differential– Backup times increase each dayBackup times increase each day– Requires only 2 tapes to restoreRequires only 2 tapes to restore

• Pages 12-5 and 12-6Pages 12-5 and 12-6

Backup ResponsibilityBackup Responsibility

• Backup user needs Read and File Backup user needs Read and File Scan rights to Scan rights to backupbackup files files– Create or write rights to Create or write rights to restorerestore

• Backup user needs passwords on Backup user needs passwords on servers (both host and target)servers (both host and target)

• MayMay need a password to the need a password to the workstation, if the target software workstation, if the target software uses oneuses one

Anti-Virus ProtectionAnti-Virus Protection

• Boot VirusesBoot Viruses– Boot Record, Master Boot Record, File Boot Record, Master Boot Record, File

Allocation Table, Partition TableAllocation Table, Partition Table• Program VirusesProgram Viruses

– Attack program filesAttack program files– .exe .com .sys .drv .ovl .bin file types.exe .com .sys .drv .ovl .bin file types

• Macro VirusesMacro Viruses– Microsoft Word virusesMicrosoft Word viruses

• Multi-partite VirusesMulti-partite Viruses– Attack the boot sector and programsAttack the boot sector and programs

Virus SymptomsVirus Symptoms

• Computer won’t startComputer won’t start• Programs won’t launch, fail easilyPrograms won’t launch, fail easily• File names/contents changedFile names/contents changed• Unusual words / graphics appearUnusual words / graphics appear• Drives get formatted Drives get formatted • Computer slows down Computer slows down

Preventing Virus InfectionPreventing Virus Infection

• Install and use one or more anti-Install and use one or more anti-virus programsvirus programs

• Scan disks regularlyScan disks regularly• Do not use unchecked disks Do not use unchecked disks • Use care when downloading / Use care when downloading /

opening email attachmentsopening email attachments• Don’t run untested programs on Don’t run untested programs on

machines with critical datamachines with critical data• UPDATE your anti-virus software!!UPDATE your anti-virus software!!

Uninterruptible Power Uninterruptible Power Supply (UPS)Supply (UPS)

• Online UPSOnline UPS– Always available, best power conditioning. Always available, best power conditioning.

Used on most critical equip.Used on most critical equip.

• Offline UPSOffline UPS– Batteries kick in when needed, delayed Batteries kick in when needed, delayed

slightly. Used on non-critical equipmentslightly. Used on non-critical equipment

• Line-interactive UPSLine-interactive UPS– Best of both. Still a delay, but smaller. Used Best of both. Still a delay, but smaller. Used

on critical equipmenton critical equipment

UPS AdvantagesUPS Advantages

• Computer Processes don’t stop Computer Processes don’t stop from power failurefrom power failure

• Data isn’t lost from spikes, surges, Data isn’t lost from spikes, surges, or blackoutsor blackouts

• Equipment is not damaged from Equipment is not damaged from spikes, surges, or blackoutsspikes, surges, or blackouts

• Longer equipment life due to Longer equipment life due to cleaner powercleaner power

RAID: Redundant Array of RAID: Redundant Array of Independent DisksIndependent Disks

• 2 or more standard disks in a single 2 or more standard disks in a single logical disk (Array) resulting in data logical disk (Array) resulting in data redundancyredundancy

• Improved I/O performanceImproved I/O performance– Load balanced across multiple disksLoad balanced across multiple disks

• Improved data reliabilityImproved data reliability– More than one copy of dataMore than one copy of data

• Simplifies storage managementSimplifies storage management– 1 logical drive to worry about1 logical drive to worry about

6 layers of RAID6 layers of RAIDHigher is not necessarily betterHigher is not necessarily better

• Level 0 Data striping and block interleaveLevel 0 Data striping and block interleave• Level 1 Disk Mirroring and DuplexingLevel 1 Disk Mirroring and Duplexing• Level 2 Data striping with bit interleaveLevel 2 Data striping with bit interleave• Level 3 Bit interleave data striping with Level 3 Bit interleave data striping with

parity checkingparity checking• Level 4 Block interleave data striping with Level 4 Block interleave data striping with

parity checkingparity checking• Level 5 Block interleave data striping with Level 5 Block interleave data striping with

distributed check-datadistributed check-data

RAID Level 0: StripingRAID Level 0: Striping

• Files are spread across disksFiles are spread across disks• This prevents requests from This prevents requests from

backing up on one disk while other backing up on one disk while other disks remain idledisks remain idle

• Spanning: data is written to next Spanning: data is written to next available diskavailable disk

• No Redundancy: failure = failureNo Redundancy: failure = failure

RAID Level 1: Mirroring or RAID Level 1: Mirroring or DuplexingDuplexing

• Reads are faster—one disk can Reads are faster—one disk can begin a seek while the other is still begin a seek while the other is still completing a seekcompleting a seek

• Write take longer—both disks are Write take longer—both disks are being written to at oncebeing written to at once

• Level 2: Not available on Personal Level 2: Not available on Personal ComputersComputers

RAID Level 3: Bit interleave Data RAID Level 3: Bit interleave Data Striping with Parity CheckingStriping with Parity Checking

• If one disk goes bad, the parity disk If one disk goes bad, the parity disk is used to reconstruct lost data. is used to reconstruct lost data. Writes continue as normal, skipping Writes continue as normal, skipping the bad diskthe bad disk

• Disks can transmit simultaneously, Disks can transmit simultaneously, giving high transfer ratesgiving high transfer rates

RAID Level 4: Block interleave Data RAID Level 4: Block interleave Data Striping with Parity CheckStriping with Parity Check

• Similar to level 3, but a block Similar to level 3, but a block interleave is used (more efficient)interleave is used (more efficient)

• Writes are a serious bottleneck Writes are a serious bottleneck potentialpotential

RAID level 5: Block interleave Data RAID level 5: Block interleave Data Striping with Distributed check-dataStriping with Distributed check-data

• More efficient with more disks usedMore efficient with more disks used• 3 disk array is 66% Efficient3 disk array is 66% Efficient• 7 disk array is 86% Efficient7 disk array is 86% Efficient• Storage Capacity is (S * N) – SStorage Capacity is (S * N) – S

– S=Size, N=number of disksS=Size, N=number of disks

Strategies, Benefits, Strategies, Benefits, Drawbacks of RAID levelsDrawbacks of RAID levels

• Table 12-2 on pages 12-16 to 12-Table 12-2 on pages 12-16 to 12-1818

• Memorize tableMemorize table

PatchesPatches

• Often there is a solution to a Often there is a solution to a problem before you know you need problem before you know you need it. Odds are, someone else has it. Odds are, someone else has experienced the problem, and the experienced the problem, and the vendor (hardware or software) may vendor (hardware or software) may have written new software to have written new software to resolve the issueresolve the issue

Patches (Con’t)Patches (Con’t)

• Latest patches will update drivers, Latest patches will update drivers, or be a patch to your OS or or be a patch to your OS or programs.programs.

• You may also need to update You may also need to update (“Flash”) your BIOS(“Flash”) your BIOS

• Typically these can be downloaded Typically these can be downloaded from the Vendor Web sitefrom the Vendor Web site

Disaster RecoveryDisaster Recovery

• Power fluctuations, viruses, worn Power fluctuations, viruses, worn hardware, misuse, natural disastershardware, misuse, natural disasters

• How critical is the data?How critical is the data?• What will downtime cost the What will downtime cost the

company per hour?company per hour?• What will be required to restore the What will be required to restore the

data?data?

Possible Possible solutions/preventionssolutions/preventions

• Mirroring/DuplexingMirroring/Duplexing• Hot swappable serversHot swappable servers• Clustered serversClustered servers• Spare partsSpare parts• Off site backupsOff site backups• UPSUPS

Recovery OptionsRecovery Options

• Restore data from backupRestore data from backup– Must have Must have current, reliablecurrent, reliable backup backup

• Use a third party package to recover Use a third party package to recover datadata– Use care to not overwrite what you want to Use care to not overwrite what you want to

recover!recover!

• Use a professional data recovery service Use a professional data recovery service ( $$ )( $$ )

• Update your resumeUpdate your resume