Configuring and Managing Data Storage

Objectives

• Understand storage options for Windows Server 2008
• Use the Disk Management tool to configure and manage storage
• Explain and configure RAID disk storage fault tolerance
• Understand storage enhancements in Windows Server 2008
• Back up disk storage

Windows Server 2008 Storage Options

• Basic disk
– One that uses traditional disk management techniques and contains primary partitions, extended partitions, and logical drives

• Dynamic disk
– One that does not use traditional partitioning

• Dynamic disk architecture provides more flexibility than basic disks
– So there is virtually no restriction on the number of volumes that can be on one disk

Basic Disks

• Partitioning
– A process that blocks a group of tracks and sectors to be used by a particular file system, such as NTFS

• Formatting
– A process that creates a table containing file and folder information for a specific file system in a partition

• Volume
– A logical designation of disk storage that is created out of one or more physical disks
– Is partitioned and formatted with one file system

• Basic disks recognize primary and extended partitions

• Basic disks also can be configured for any of three RAID levels:
– Disk striping (RAID level 0)
– Disk mirroring (RAID level 1)
– Disk striping with parity (RAID level 5)

• RAID stands for redundant array of inexpensive (or independent) disks
– A set of standards for lengthening disk life and preventing data loss

• MBR and GPT support
– When a drive is partitioned, a Master Boot Record (MBR) and a partition table are created

• At the beginning track and sectors on the disk
– The MBR is located in the first sector and track of the hard disk

• Has startup information about partitions and how to access the disk
– The partition table contains information about each partition created

• MBR and GPT support (continued)
– Globally Unique Identifier (GUID) Partition Table or GPT

• A newer way to partition disks, without imposing the same type of limits on the number of partitions as with MBR
– GPT is one element of the Extensible Firmware Interface (EFI) approach

• Offered by the Unified EFI Forum
– GPT disks store partition information in each partition using main and backup tables

• Primary and extended partitions on MBR disks
– A primary partition is one from which you can boot an operating system
– At least one primary partition must be marked as active

• Only one primary partition can be active at a given time
– The active partition is the partition where your computer will look for the hardware-specific files to start the operating system

• Primary and extended partitions on MBR disks (continued)
– An extended partition is created from space that is not yet partitioned
– The purpose of an extended partition is to enable you to exceed the four-partition limit of a basic disk
– Only one extended partition can exist on a single basic disk

• A computer with multiple partitions boots from the partition that is designated as the active partition
– Must also be the system partition

• Volume and Stripe Sets
– Volume set

• Consists of two or more partitions that are combined to look like one volume with a single drive letter
– Stripe set

• Two or more disks that are combined like a volume set, but that are striped for RAID level 0 or RAID level 5

Dynamic Disks

• A dynamic disk does not use traditional partitioning
– Makes it possible to set up a large number of volumes on one disk
– Provides the ability to extend volumes onto additional physical disks

• The number of disks that can be incorporated into one spanned volume is limited to 32
• Plan to convert basic disks to dynamic disks after you install Windows Server 2008

• Simple volume
– A portion of a disk or an entire disk that is set up as a dynamic disk
– Can be extended onto multiple sections of the same disk

• Spanned volume
– Stored on 2 to 32 dynamic disks that are treated as one volume
– As you add new disks, the spanned volume can be extended to include each disk

• Striped volumes
– Often referred to as RAID-0
– Extend the life of hard disk drives by spreading data equally over two or more drives
– Another advantage: increases disk performance
– In Windows Server 2008, striping requires at least two disks and can be performed over as many as 32
– Data can be lost when one or more disks in the striped volume fail because the system has no automated way to rebuild data

• Shrinking a volume
– Windows Server 2008 comes with the ability to shrink a basic or dynamic disk volume
– Shrinking a volume enables you to create a new partition when one is needed and you don’t have extra disks
– When you shrink a volume, Windows Server 2008 starts from the end of that volume

• Works its way back through contiguous space to create unallocated disk space
– You can specify the amount of space to recover

Disk Management

• Disk Management tool
– Provides a central location for viewing disk information and performing tasks such as creating and deleting partitions and volumes

Creating a Partition and Simple Volume

• Partitions operate as separate storage units on a hard disk

• The most basic way to create a partition is to take unallocated disk space
– Use the New Simple Volume Wizard to create a simple volume

• You can also delete a partition using the Disk Management tool
• Once a partition is formatted, it is called a volume and can be assigned a drive letter

Mounting a Drive

• Windows Server 2008 enables you to mount a drive as an alternative to giving it a drive letter

• Mounted drive
– One that appears as a folder and is accessed through a path like any other folder

• You can mount a basic or dynamic disk drive, a CD/DVD drive, or a removable drive

• Home directory or home folder
– A server folder that is associated with a user’s account and that is a designated workspace for the user to store files

Managing Disks

• Using Disk Defragmenter
– When you save a file to a disk, Windows Server 2008 saves the file to the first area of available space
– The file might not be saved to a contiguous area of free space

• The disk gradually becomes fragmented

• The process of defragmenting
– Locates fragmented folders and files and moves them to a location on the physical disk so they are in contiguous order

• Using Disk Check
– The Disk Check tool allows you to scan your disk for bad sectors and file system errors

• This tool is meant for use when no users need to access the files on the disk you want to check
– Because the disk is made unavailable during the scan for problems

• Options:
– Automatically fix file system errors
– Scan for and attempt recovery of bad sectors

• Using chkdsk
– You can also check your disk for errors by running the chkdsk utility from the Command Prompt window
– In NTFS, chkdsk checks files, folders, indexes, security descriptors, user files, sectors, and disk allocation units

Introduction to Fault Tolerance

• Fault tolerance
– The ability of a system to gracefully recover from hardware or software failure

• Windows Server 2008 provides a level of fault tolerance through software-level RAID

• With fault tolerance, data is written to more than one drive
– In the event one drive fails, data can still be accessed from one of the remaining drives

RAID Volumes

• RAID is a set of standards for lengthening disk life, preventing data loss, and enabling relatively uninterrupted access to data

• RAID level 0
– Striping with no other redundancy features is RAID level 0

• RAID level 1
– Disk duplexing is the same as disk mirroring, with the exception that it places the backup disk on a different controller or adapter than is used by the main disk

• RAID level 2
– Uses an array of disks whereby the data is striped across all disks in the array

• RAID level 3
– Uses disk striping and stores error-correcting information, but the information is only written to one disk in the array

• RAID level 4
– Stripes data and stores error-correcting information on all drives

• RAID level 5
– Combines the best features of RAID, including striping, error correction, and checksum verification

• Windows Server 2008 supports RAID levels 0, 1, and 5 for disk fault tolerance

Using a Striped Volume (RAID-0)

• Reasons for using a RAID level 0 or a striped volume in Windows Server 2008 are to:
– Reduce the wear on multiple disk drives by equally spreading the load
– Increase disk performance compared with other methods for configuring dynamic disk volumes

• To create a striped volume, right-click the unallocated space for the volume and click New Striped Volume
• Only dynamic disks can be striped volumes

Using a Mirrored Volume (RAID-1)

• Disk mirroring involves creating a shadow copy of data on a backup disk
• Only dynamic disks can be set up as a mirrored volume in Windows Server 2008
• One of the most guaranteed forms of disk fault tolerance
• Disk read performance is the same as reading data from any single disk drive
• A mirrored volume is created through the Disk Management tool

Using a RAID-5 Volume

• Fault tolerance is better for a RAID-5 volume
• A RAID-5 volume requires a minimum of three disk drives

• Parity information is distributed on each disk
– If one disk fails, the information on that disk can be reconstructed
– The parity used by Microsoft is Boolean (true/false, one/zero) logic

• The performance is not as fast as with a striped volume
– Takes longer to write the data and calculate the parity block for each row

• Accessing data through disk reads is as fast as a striped volume
• A RAID-5 volume is particularly useful in a client/server system that uses a separate database for queries and creating reports
• Use the Disk Management tool to create a RAID-5 volume

Software RAID vs. Hardware RAID

• Software RAID implements fault tolerance through the server’s operating system

• Hardware RAID is implemented through the server hardware
– Independent of the operating system

• Advantages over software RAID:
– Faster read and write response
– The ability to place boot and system files on different RAID levels
– The ability to ‘‘hot-swap’’ a failed disk
– More setup options to retrieve damaged data

Windows Server 2008 Storage Enhancements

• For medium to large networks, Windows Server 2008 offers storage enhancements in two important realms:
– Management of Storage Area Networks
– Using multiple paths to storage for fault tolerance

Storage Manager for SANs

• Storage Area Network (SAN)
– A grouping of storage devices that forms a subnet

• The storage devices are available to any server on the main network
– Appear to the user as though they are attached to the server they are accessing

• Typically, the subnet containing the storage devices uses Fibre Channel or iSCSI technology
• Storage Manager for SANs is used to manage the logical unit numbers for Small Computer System Interface drives

• Small Computer System Interface (SCSI)
– A 32- or 64-bit computer adapter that transports data between one or more attached devices and the computer

• Logical unit number (LUN)
– A number that identifies a physical SCSI drive or logical SCSI targets

• A SAN containing multiple drives configured for RAID will have many LUNs to manage
• Storage Manager for SANs is used for SANs that employ Virtual Disk Service

• Virtual Disk Service (VDS)
– Used to enable management of disk volumes in SANs through one interface at a server

• Another enhancement to Windows Server 2008 is that the iSCSI initiator is now built into the operating system
– The iSCSI initiator is a driver that enables Windows Server 2008 to communicate with an iSCSI SAN

Multipath Input/Output Enhancements

• Multipath I/O
– Provides a means to establish multiple paths between a server and its disk storage

• The first step in this process is to create the multiple paths between the storage and the server or servers
– For a SAN, creating multiple paths might involve establishing two or more network paths through two or more network switches to the SAN

• The next step is to install Multipath I/O
– A feature installed through Server Manager

• Device Specific Module (DSM)
– Compatible with the following disk storage array controller technologies:

• Asymmetric logical unit access (ALUA)
• Active/Active controller model

• Configuration models:
– Dynamic Least Queue Depth
– Failback
– Failover
– Round Robin
– Round Robin with a subset of paths
– Weighted Path

Disk Backup

• One of the best ways to make sure you do not lose valuable information on a hard disk is to fully back up information on a regular basis
– These backups can be performed from the server or from a workstation on the network

• Performing backups from a backup device installed on the server has several advantages:
– No extra load is produced on the network
– Perform backups on a multiple-server network
– Provides more assurance that the Registry is backed up

• The advantages of performing a network backup
– Backup jobs can be stored on a single backup media
– One administrator can be responsible for backing up multiple servers

• The main disadvantages
– The increase in network traffic
– The Registry cannot be backed up from across the network

Windows Server Backup

• Windows Server Backup tool offers the ability to back up all server files or files that have changed

• Enhancements in Windows Server 2008:
– Is easier to recover from a backup
– Has more backup options, including using the Volume Shadow Copy Service (VSS)
– Is more reliable in recovering applications
– Provides information about disk use
– Offers the wbadmin command-line tool
– Has full support to back up to optical media

• Considerations for using Windows Server Backup
– Tool only backs up NTFS volumes
– Tool does not back up to tape
– If you have backup media made from Windows Server 2003 using Ntbackup.exe, you cannot restore from that media using the Windows Server Backup tool in Windows Server 2008

Backup Options

• Full backup
– A backup of an entire system, including all system files, programs, and data files
– Changes each file’s archive attribute to show that it has been backed up

• Incremental backup
– Only backs up files that are new or that have been updated
– Backs up only files that have the archive attribute marked

• Custom backup
– Enables you to configure backups differently for each volume

• Such as doing an incremental backup every time you back up the C drive and a full backup each time you back up the D drive

Scheduling Backups

• Windows Server Backup includes a scheduling capability
– Can have the server automatically start backups after regular work hours or at a specific time of day

Configuring Backup Performance

• Configuring the backup performance options enables you to specify which types of backups to perform: full, incremental, and custom
• The default is to always perform full backups

Performing a Recovery

• The Windows Server Backup tool enables you to recover any of the following:
– Files
– Folders
– Volumes
– Applications and application data
– The backup catalog (of information in the backup)
– The operating system (to the same computer or to another computer using identical hardware)

• Before you start, determine the following information:
– Date of the backup from which to recover
– Type of recovery, such as files and folders or applications
– What to recover
– Where to recover, such as in the original location or another location

Summary

• Windows Server 2008 uses basic and dynamic disks
• Dynamic disks can be configured as simple, spanned, striped, mirrored, and RAID-5 volumes
• If you need to recover space from a basic or dynamic disk, you can shrink the disk
• The Disk Management tool enables you to create basic and dynamic disks
• For optimum disk performance, plan to set up a schedule to regularly defragment disks on a server
• Use the Disk Check and chkdsk tools to find and repair disk problems
• RAID provides fault tolerance for hard disks
• RAID level 0 is disk striping
• With disk mirroring or duplexing (RAID level 1), the same data is written to a partition on each of the two disks included in the mirror
• With RAID level 5, data is written across a minimum of three disks
• Two important enhancements for Windows Server 2008 include new features for Storage Manager for SANs and features for Multipath I/O
• Windows Server Backup offers features to schedule backups, perform full or incremental backups (or a combination of both), and recover data from backups