Chapter 6

Chapter 6: Configuring Server Storage, Backup, and Performance Options

Chapter 6: Configuring Server Storage, Backup, and Performance Options

Chapter 6

Learning ObjectivesLearning Objectives

Partition and format hard disksPartition and format hard disks Explain types of disk partitionsExplain types of disk partitions Create volume setsCreate volume sets Extend a disk volumeExtend a disk volume Implement disk redundancy through Implement disk redundancy through

striped sets, striped sets with parity, and striped sets, striped sets with parity, and mirrored setsmirrored sets

continued

Chapter 6

Learning ObjectivesLearning Objectives

Perform disk backupsPerform disk backups Develop a tape rotation schemeDevelop a tape rotation scheme Configure server memory to improve Configure server memory to improve

performanceperformance Configure Windows NT Server for a Configure Windows NT Server for a

UPSUPS

Chapter 6

Hard Disk BasicsHard Disk Basics

Low-level formatLow-level format A software process that marks tracks and A software process that marks tracks and

sectors on a disksectors on a disk Necessary before a disk can be partitioned Necessary before a disk can be partitioned

and formattedand formatted TracksTracks

Concentric rings that cover an entire diskConcentric rings that cover an entire disk Each ring is divided into sectors in which data Each ring is divided into sectors in which data

are storedare stored

Chapter 6

Hard Disk BasicsHard Disk Basics

SectorsSectors A portion of a disk trackA portion of a disk track Disk tracks are divided into equal Disk tracks are divided into equal

segments, or sectorssegments, or sectors Other nomenclatureOther nomenclature

tracks also known as “cylinders”tracks also known as “cylinders” ““heads” are number of r/w devicesheads” are number of r/w devices LBA = logical block addressLBA = logical block address

Chapter 6

A Disk Divided into Tracks and Sectors

A Disk Divided into Tracks and Sectors

Tracks

Sectors within a

track

Chapter 6

Disk PartitionsDisk Partitions

PartitioningPartitioning: The process of marking a : The process of marking a group of tracks and sectors in group of tracks and sectors in preparation for a file systempreparation for a file system breaks a physical disk into logical volumesbreaks a physical disk into logical volumes

Free spaceFree space: Disk space not yet : Disk space not yet partitioned for use by a file or operating partitioned for use by a file or operating systemsystem different from “free space” (i.e. space different from “free space” (i.e. space

available to store files) within a volumeavailable to store files) within a volume

Chapter 6

Disk PartitionsDisk Partitions

Master boot record (MBR)Master boot record (MBR): Data stored in : Data stored in the first sector of a disk, including startup the first sector of a disk, including startup information and information about disk information and information about disk partitionspartitions

Partition tablePartition table Table containing information about each Table containing information about each

partition on a diskpartition on a disk Provides information to the computer about Provides information to the computer about

how to access the disk how to access the disk

Chapter 6

Disk PartitionsDisk Partitions

Boot loaderBoot loader mini-program, lives in MBR or first sector of partitionmini-program, lives in MBR or first sector of partition presents menu of boot choices to userpresents menu of boot choices to user generally has timeout and default choicegenerally has timeout and default choice

Various choicesVarious choices NT boot loaderNT boot loader OS/2 boot managerOS/2 boot manager Linux “LILO”Linux “LILO” generally, independent of the OSgenerally, independent of the OS

Chapter 6

Primary and Extended PartitionsPrimary and Extended Partitions

Primary partitionPrimary partition: Partition or portion of : Partition or portion of a hard disk that is bootablea hard disk that is bootable

Extended partitionExtended partition: Partition that is : Partition that is created from (otherwise) unpartitioned created from (otherwise) unpartitioned disk space; contains “logical partitions”disk space; contains “logical partitions”

Chapter 6

Entering the Partition SizeEntering the Partition Size

Chapter 6

Partition TypesPartition Types

Active partitionActive partition: Partition from which a : Partition from which a computer boots, or startscomputer boots, or starts can change active partition to enable can change active partition to enable

booting of other OSsbooting of other OSs Boot partitionBoot partition: Partition that holds the : Partition that holds the Windows NT\WinntWindows NT\Winnt folder containing folder containing the system filesthe system files boot partition gets special treatment by OSboot partition gets special treatment by OS

Chapter 6

FormattingFormatting

FormattingFormatting: A process that prepares a : A process that prepares a hard disk partition for a specific file hard disk partition for a specific file systemsystem

VolumeVolume: loosely defined as “an amount : loosely defined as “an amount of storage”. Can be a partition (any of storage”. Can be a partition (any sort), a stripe set, etc. Generally seen sort), a stripe set, etc. Generally seen by users as a drive letter (ex. D:) no by users as a drive letter (ex. D:) no matter what it’s made up of.matter what it’s made up of.

Chapter 6

FormattingFormatting

Assigning a drive letterAssigning a drive letter

Chapter 6

Creating Volume SetsCreating Volume Sets

Volume setVolume set: Two or more formatted partitions : Two or more formatted partitions (volumes) that are combined to look like one (volumes) that are combined to look like one volume with a single drive lettervolume with a single drive letter

AdvantageAdvantage Ability to manage several small disk drives more Ability to manage several small disk drives more

easily or to maximize the use of scattered pockets of easily or to maximize the use of scattered pockets of disk space across several disksdisk space across several disks

DisadvantageDisadvantage If one disk in the volume set fails, the entire volume If one disk in the volume set fails, the entire volume

is inaccessibleis inaccessible

Chapter 6

Extending a VolumeExtending a Volume

Add (e.g.) another disk until larger disk Add (e.g.) another disk until larger disk drives are purchaseddrives are purchased increases available space to usersincreases available space to users

Same risks as volume setSame risks as volume set disk failuredisk failure

Chapter 6

Implementing Disk RedundancyImplementing Disk Redundancy

Operating system disk protectionOperating system disk protection Disk stripingDisk striping Striping with parityStriping with parity Disk mirroringDisk mirroring

Chapter 6

Operating System Disk Protection

Operating System Disk Protection

Hot fixHot fix: A data recovery method that : A data recovery method that automatically stores data elsewhere automatically stores data elsewhere when a damaged area of disk prevents when a damaged area of disk prevents that data from being writtenthat data from being written

• ““Hot” because it happens without interruption to the Hot” because it happens without interruption to the systemsystem

Chapter 6

Operating System Disk Protection

Operating System Disk Protection

Sector sparingSector sparing: A fault-tolerance method : A fault-tolerance method that reserves certain hard disk sectors so that reserves certain hard disk sectors so that they can be used when a bad sector is that they can be used when a bad sector is discovereddiscovered

Cluster remappingCluster remapping: A fault-tolerance : A fault-tolerance technique that flags a damaged cluster and technique that flags a damaged cluster and finds an undamaged cluster on which to finds an undamaged cluster on which to write datawrite data ““cluster” is mostly analogous to a sectorcluster” is mostly analogous to a sector

Chapter 6

Disk StripingDisk Striping

Stripe setStripe set: Two or more disks set up so : Two or more disks set up so that files are spread in blocks across the that files are spread in blocks across the disksdisks

Disk 1 Disk 2 Disk 3 Disk 4 Disk 5

Row 2

Row 1

Row 3

Chapter 6

Disk StripingDisk Striping

AdvantagesAdvantages speeds access to dataspeeds access to data

rotational and seek latenciesrotational and seek latencies spreads out wear & tearspreads out wear & tear

DisadvantagesDisadvantages if one disk fails, can’t re-create dataif one disk fails, can’t re-create data

different options (RAID levels) address thisdifferent options (RAID levels) address this

TradeoffsTradeoffs one adapter for all disks, or one eachone adapter for all disks, or one each

Chapter 6

Stripe set with parityStripe set with parity: Three or more : Three or more disks in which files are spread across disks in which files are spread across the disks in blocks, and a parity block is the disks in blocks, and a parity block is written on each disk to enable data written on each disk to enable data recovery should one disk in the set failrecovery should one disk in the set fail

Striping with ParityStriping with Parity

Row 2

Row 1

Row 3

Disk 1 Disk 2 Disk 3 Disk 4 Disk 5

Parity block

Parity block

Parity block

Chapter 6

Definition of “parity”Definition of “parity” the result of a mathematical function the result of a mathematical function

performed on the data, which can be used performed on the data, which can be used to reconstruct what the original data wereto reconstruct what the original data were There must be 3 or more disks to do thisThere must be 3 or more disks to do this

Recall server hardware discussionRecall server hardware discussion hot-swap disks versus power-down, etc.hot-swap disks versus power-down, etc.

Striping with ParityStriping with Parity

Chapter 6

Disk MirroringDisk Mirroring

Involves creating a “shadow” copy of data on Involves creating a “shadow” copy of data on a backup diska backup disk

also “duplexing” - different adaptersalso “duplexing” - different adapters

AdvantagesAdvantages Most guaranteed form of disk fault toleranceMost guaranteed form of disk fault tolerance Well suited for mission-critical dataWell suited for mission-critical data

DisadvantagesDisadvantages Doubles time needed to create or update Doubles time needed to create or update

informationinformation

Chapter 6

Increasing Disk Performance and Longevity

Increasing Disk Performance and Longevity

Make sure that one disk is not working Make sure that one disk is not working harder (e.g. accessed more often) than harder (e.g. accessed more often) than other disks in a multiple-disk serverother disks in a multiple-disk server Use striping or striping with parityUse striping or striping with parity Relocate files to distribute disk access more Relocate files to distribute disk access more

evenlyevenly Use defragmenting to reorganize files to Use defragmenting to reorganize files to

reduce the number of empty spaces reduce the number of empty spaces between filesbetween files

Chapter 6

Disk Security Through Backup Techniques

Disk Security Through Backup Techniques

Advantages of Advantages of locallocal (eg. one per server) tape (eg. one per server) tape drive backupsdrive backups Causes no extra load on networkCauses no extra load on network Can perform backups on a multiple server network Can perform backups on a multiple server network

even if one tape drive failseven if one tape drive fails Provides more assurance that the Registry is Provides more assurance that the Registry is

backed upbacked up Can also back up on other mediaCan also back up on other media

Jaz disks, ZIP disks, writable CD-ROMs, etc. Jaz disks, ZIP disks, writable CD-ROMs, etc. another hard drive (disaster recovery)another hard drive (disaster recovery)

Chapter 6

Disk Security Through Backup Techniques

Disk Security Through Backup Techniques

Full backupFull backup: Backs up all volumes, : Backs up all volumes, directories, and files directories, and files

Incremental backupIncremental backup: Backs up only : Backs up only those files that have changed since the those files that have changed since the previous backupprevious backup

generally, much smaller than full backupgenerally, much smaller than full backup quicker to performquicker to perform less media needed (number of tapes)less media needed (number of tapes)

Chapter 6

Backup OptionsBackup Options

NormalNormal: Same as full file-by-file backup: Same as full file-by-file backup CopyCopy: Only files or directories selected: Only files or directories selected IncrementalIncremental: Only files with archive : Only files with archive

attributeattribute DifferentialDifferential: Same as incremental but : Same as incremental but

does not remove archive attributedoes not remove archive attribute DailyDaily: Only files that have been : Only files that have been

changed/updated on the day of backupchanged/updated on the day of backup

Chapter 6

Tape RotationTape Rotation

Helps ensure alternatives in case there is Helps ensure alternatives in case there is a bad or worn tapea bad or worn tape e.g., Tower of Hanoi procedure: Rotates e.g., Tower of Hanoi procedure: Rotates

tapes so that some are used more frequently tapes so that some are used more frequently than othersthan others

depends on importance of data, budget for depends on importance of data, budget for tapes, skill and time of backup operatortapes, skill and time of backup operator

Consider off-site storage for disaster Consider off-site storage for disaster recoveryrecovery

Chapter 6

Configuring a Server to Improve Performance

Configuring a Server to Improve Performance

Configuring virtual memoryConfiguring virtual memory Configuring memory to match the user Configuring memory to match the user

loadload

Chapter 6

Configuring Virtual MemoryConfiguring Virtual Memory

Virtual memoryVirtual memory: Disk space allocated to : Disk space allocated to temporarily hold data when there is not enough temporarily hold data when there is not enough free RAMfree RAM much slower than RAM (e.g. not a replacement)much slower than RAM (e.g. not a replacement)

PagingPaging: Moving blocks of information from RAM : Moving blocks of information from RAM to virtual memory on disk to virtual memory on disk

Page filePage file: Disk space reserved for use when : Disk space reserved for use when memory requirements exceed available RAMmemory requirements exceed available RAM General rule for sizing = Amount of installed RAM + 12 General rule for sizing = Amount of installed RAM + 12

MBMB

Chapter 6

Configuring Virtual MemoryConfiguring Virtual Memory

System “swaps out” pages to disk as neededSystem “swaps out” pages to disk as needed ex. when multitasking, use RAM for current program, put ex. when multitasking, use RAM for current program, put

others on disk temporarilyothers on disk temporarily happens automatically; neither user nor programmer happens automatically; neither user nor programmer

has to do anythinghas to do anything Can dramatically affect performanceCan dramatically affect performance

sometimes greatly increases contention for the disk sometimes greatly increases contention for the disk containing the pagefilecontaining the pagefile

if misused, system spends all its time copying data and if misused, system spends all its time copying data and very little doing actual useful workvery little doing actual useful work

adding RAM memory (e.g., avoiding VM) is betteradding RAM memory (e.g., avoiding VM) is better

Chapter 6

Configuring Memory to Match the User Load

Configuring Memory to Match the User Load

Server functionsServer functions Use RAM and pagingUse RAM and paging

Software applicationsSoftware applications PrintingPrinting Currently running servicesCurrently running services

Network connectivity functionsNetwork connectivity functions Use RAM onlyUse RAM only

Number of user connectionsNumber of user connections

Chapter 6

Configuring Server RAM HintsConfiguring Server RAM Hints

Optimizing MemorySettings

Purpose

Minimize MemoryUsed

Optimizes the memory used on servers with10 or fewer simultaneous network users

Balance Optimizes memory use for a small LAN with64 or fewer users

MaximizeThroughput for FileSharing

Used for a large network with 64+ userswhere file serving resources need morememory allocation to make server efficient

MaximizeThroughput forNetwork Apps

Used on dedicated database servers in aclient/server application environment

Chapter 6

UPS Fault ToleranceUPS Fault Tolerance

Uninterruptible power supply (UPS)Uninterruptible power supply (UPS): A device : A device that provides immediate battery power to that provides immediate battery power to equipment during a power failure or brownout for equipment during a power failure or brownout for a limited time perioda limited time period

Online UPSOnline UPS: Battery backup device that provides : Battery backup device that provides power to equipment directly from its batteries at power to equipment directly from its batteries at all timesall times

Offline UPSOffline UPS: Battery backup device that waits : Battery backup device that waits until there is a power decrease or sag before until there is a power decrease or sag before switching to battery powerswitching to battery power

Chapter 6

Chapter SummaryChapter Summary

Properly setting up disk storage is as Properly setting up disk storage is as important as selecting it. important as selecting it. Partition disk drives through the Disk AdministratorPartition disk drives through the Disk Administrator

After partitions are set up and formatted, After partitions are set up and formatted, implement a fault-tolerance method.implement a fault-tolerance method. Disk stripingDisk striping Striping with parityStriping with parity Disk mirroringDisk mirroring

continued

Chapter 6

Chapter SummaryChapter Summary

Disk performance affected byDisk performance affected by FragmentationFragmentation Distribution of files across multiple disksDistribution of files across multiple disks RAM configurationRAM configuration Virtual memoryVirtual memory

continued

Chapter 6

Chapter SummaryChapter Summary

Establish a tape backup method to Establish a tape backup method to guard against data loss.guard against data loss. Full and partial backup techniquesFull and partial backup techniques Tape rotationTape rotation

Also, can protect against power outages Also, can protect against power outages with a UPSwith a UPS