Transcript Chapter 6 - Planning Storage Solution

Planning Storage Solutions
Lesson 6
Server Storage
• The I/O burdens of a server are quite different from
those of a workstation, and a standard storage subsystem
can easily be overwhelmed by file requests from dozens
or hundreds of users.
• In addition, standard hard disks offer no fault tolerance
and are limited in their scalability.
Server Storage
• Designing a storage solution for a server depends on
several factors, including the following:
– The amount of storage the server needs.
– The number of users that will be accessing the server at
the same time.
– The sensitivity of the data to be stored on the server.
– The importance of the data to the organization.
Estimating Storage Requirements
• Other storage requirement
– Operating system
– Paging file
– Memory dump
– Log files
– Shadow copies
– Fault tolerance
Disk Technology
• Direct-Attached Storage
– Advanced Technology Attachment (ATA)
• Parallel ATA
• Serial ATA
– Small Computer System Interface (SCSI)
Small Computer System Interface (SCSI)
• You connect SCSI devices to a host
adapter using a daisy chain cable
arrangement called a SCSI bus.
• To use SCSI on a server, all of the
devices and host adapters must
support the same standard.
• Every device on a SCSI bus has an
identifier called a SCSI ID, which the
host adapter uses to send commands
to the device.
• Subcomponents of a SCSI device, such
as individual drives in an array, are
identified using logical unit numbers
(LUNs).
External Drive Arrays
• High capacity servers often store hard drives in a
separate housing, called an external drive array,
which typically incorporates a disk controller,
power supply, cooling fans, and cache memory
into an independent unit.
• Drive arrays can connect to a computer using a
disk interface, such as SCSI (Small Computer
System Interface), IEEE 1394 (FireWire), or USB
3.0, or a network interface, such as iSCSI or Fibre
Channel.
Network Attached Storage
Storage Area Network (SAN)
Planning for Storage Fault Tolerance
• Redundant Array of Independent Disks
– Disk mirroring (RAID 1)
• Disk duplexing
– Strip set with Distributed Parity (RAID 5)
Windows Disk Settings
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Select a partitioning style (MBR or GPT).
Select a disk type (Basic versus Dynamic).
Divide the disk into partitions or volumes.
Format the partition with a file system.
Partition Style
• Windows Server 2008 computers can use either one of
the following two hard disk partition styles:
– MBR — The MBR partition style has been around since
before Windows and is still the default partition style for
x86-based and x64-based computers.
– GPT — GPT has also been around for a while, but no x86
version of Windows prior to Windows Server 2008 and
Windows Vista supports it. (Windows XP Professional x64
Edition does support GPT.) Now you can use the GPT
partition style on x86-, as well as x64-based, computers.
Partition Style
Basic Disks
• A basic disk uses primary partitions, extended
partitions, and logical drives to organize data.
• A primary partition appears to the operating
system as though it is a physically separate disk
and can host an operating system, in which case it
is known as the active partition.
Partitions
Volume Types
• A dynamic disk can contain an unlimited number
of volumes that function much like primary
partitions on a basic disk, but you cannot mark an
existing dynamic disk as active.
– Simple Volume
– Spanned Volume
– Striped Volume
– Mirrored Volume
– RAID-5 Volume
Volume Size
• Although Windows Server 2008 can support
dynamic volumes as large as 64 terabytes, this
does not mean that you should create volumes
that big, even if you have a server with that much
storage.
• To facilitate the maintenance and administration
processes, it is usually preferable to split your
server’s storage into volumes of manageable size,
rather than create a single, gigantic volume.
Disk Management
• Disk Management is a Microsoft Management Console
(MMC) snap-in that you use to perform disk-related
tasks, such as the following:
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Initializing disks.
Selecting a partition style.
Converting basic disks to dynamic disks.
Creating partitions and volumes.
Extending, shrinking, and deleting volumes.
Formatting partitions and volumes.
Assigning and changing driver letters and paths.
Examining and managing physical disk properties, such as
disk quotas, folder sharing, and error checking.
Extending Volumes
• Windows Server 2008 extends existing volumes
by expanding them into adjacent unallocated
space on the same disk.
• When you extend a simple volume across multiple
disks, the simple volume becomes a spanned
volume.
• You cannot extend striped volumes.
Extending Volumes
• To extend a volume on a basic disk, the system must
meet the following requirements:
– A volume of a basic disk must be either unformatted or
formatted with the NTFS file system.
– If you extend a volume that is actually a logical drive, the
console first consumes the contiguous free space
remaining in the extended partition.
– You can extend logical drives, boot volumes, or system
volumes only into contiguous space, and only if the hard
disk can be upgraded to a dynamic disk.
Extending Volumes
• To extend a volume on a dynamic disk, the system must
meet these requirements:
– When extending a simple volume, you can use only the
available space on the same disk, if the volume is to
remain simple.
– You can extend a simple volume across additional disks if it
is not a system volume or a boot volume.
– You can extend a simple or spanned volume if it does not
have a file system (a raw volume) or if you formatted it
using the NTFS file system.
– You cannot extend mirrored or RAID-5 volumes.
Shrinking Volumes
• When shrinking volumes, the Disk Management
console frees up space at the end of the volume,
relocating the existing volume’s files, if necessary.
• The console then converts that free space to new
unallocated space on the disk.
Shrinking Volumes
• To shrink basic disk volumes and simple or spanned
dynamic disk volumes, the system must meet the
following requirements:
– The existing volume must not be full and must contain the
specified amount of available free space for shrinking.
– The volume must not be a raw partition (one without a file
system).
– You can shrink a volume only if you formatted it using the
NTFS file system.
– You cannot shrink striped, mirrored, or RAID-5 volumes.
– You should always defragment a volume before you
attempt to shrink it.
Storage Area Network
Multiple Servers Connected to a SAN
Fibre Channel
• Fibre Channel is a high-speed serial networking
technology, originally designed for use with
supercomputers but now associated primarily with
storage area networking.
• Fibre Channel supports various network media,
transmission speeds, topologies, and upper level
protocols.
• Its primary disadvantage is that it requires specialized
hardware that can be extremely expensive.
Fibre Channel Media
• A Fibre Channel network can use a variety of network
media.
• Copper alternatives include video or miniature coaxial
cable and, more commonly, shielded twisted pair (STP)
with DB-9 or HSSDC (High Speed Serial Data Connection)
cable connectors.
• Fiber optic alternatives include 62.5- or 50-ohm
multimode and 7- or 9-ohm singlemode, all using LC or
SC connectors.
• Because Fibre Channel it can span much longer distances
than a pure SCSI connection, up to 50 kilometers or more
in some cases.
Fibre Channel Speeds
• Transmission speeds for Fibre Channel networks
range from 133 Mbps (megabits per second) to 1
Gbps (gigabit per second) for copper cables, and
up to 10 Gbps for fiber optic.
• Maximum speeds depend on the type of cable the
network uses, the lengths of the cable segments,
and, in the case of fiber optic, the type of laser
used to transmit the signals.
Fibre Channel Topologies
• Point-to-point (FC-P2P) — Consists of two devices
only, directly connected with a single cable.
• Arbitrated loop (FC-AL) — Consists of up to 127
devices, connected in a loop topology, similar to
that of a token ring network.
– The loop can be physical, with each device connected
to the next device, or virtual, with each device
connected to a hub that implements the loop.
Fibre Channel Topologies
• Switched fabric (FC-SW) — Consists of up to
16,777,216 (224) devices, each of which is
connected to a Fibre Channel switch.
• Unlike Ethernet switches, Fibre Channel switches
provide redundant paths between the connected
devices, forming a topology called a mesh or
fabric.
• If a switch or a connection between switches fails,
data can find an alternate path through the fabric
to its destination.
iSCSI
• iSCSI is an alternative storage area networking
technology that enables servers and storage
devices to exchange SCSI traffic using a standard
IP network instead of a dedicated Fibre Channel
network.
• Because iSCSI uses a standard IP network for its
lower layer functionality, you can use the same
cables, network adapters, switches, and routers
for a SAN as you would for a LAN or wide area
network (WAN), without any modifications.
iSCSI
• iSCSI communication is based on two elements:
– Initiators
– Targets
iSCSI Initiator
• Initiates the SCSI communication process.
• Is a hardware or software device
• The initiator receives I/O requests from the operating
system and sends them, in the form of SCSI commands,
to specific storage devices on the SAN.
• The only difference between an iSCSI initiator and a SCSI
host adapter is that the initiator packages the SCSI traffic
in TCP/IP packets, instead of using the native SCSI
protocols.
iSCSI Target
• Integrated into a drive array or computer.
• The target receives SCSI commands from the initiator and
passes them to a storage device, which is represented by
a logical unit number (LUN).
• A LUN is essentially an address that SCSI devices use to
identify a specific storage resource.
• A single LUN can represent an entire hard disk, part of a
disk, or a slice of a RAID array.
iSNSs
• After the initiators and targets are in place, the only
problem remaining in iSCSI communications is how the
two locate each other.
• The Internet Storage Name Service (iSNS) makes this
possible by registering the presence of initiators and
targets on a SAN and responding to queries from iSNS
clients.
• Windows Server 2008 includes an iSNS implementation
as a feature, which can provide the identification service
for an entire SAN.
iSNS Components
• iSNS server — Receives and processes registration requests
and queries from clients on the SAN, using the iSNS database
as an information store.
• iSNS database — Information store on an iSNS server that
contains data supplied by client registrations. The server
retrieves the data to respond to client queries.
• iSNS clients — Component in iSCSI initiators and targets that
registers information about itself with an iSNS server and
sends queries to the server for information about other
clients.
• iSNS Protocol (iSNSP) — Protocol used for all registration and
query traffic between iSNS servers and clients.
Summary
• Windows Server 2008 supports two hard disk
partition types: MBR and GPT; two disk types:
basic and dynamic; five volume types: simple,
striped, spanned, mirrored, and RAID-5; and two
file systems: NTFS and FAT.
• The Disk Management snap-in is the primary
interface you use to initialize, partition, and
format disks.
Summary
• A storage area network (SAN) is a network
dedicated solely to high-speed connections
between servers and storage devices.
• Fibre Channel is a high-speed serial networking
technology that was originally designed for use
with supercomputers but is now associated
primarily with storage area networking.
Summary
• iSCSI is an alternative storage area networking
technology that enables servers and storage
devices to exchange SCSI traffic using a standard
IP network instead of a dedicated Fibre Channel
network.
Summary
• An iSCSI initiator is a hardware or software device
running on a computer that accesses the storage
devices on the SAN.
• The other half of the iSCSI equation is the iSCSI
target, which receives SCSI commands from the
initiator and passes them to a storage device,
represented by a logical unit number (LUN).
Summary
• The Internet Storage Name Service (iSNS) registers the
presence of initiators and targets on a SAN and responds
to queries from iSNS clients.
• Storage Manager for SANs can manage only storage
devices that include support for the Microsoft Virtual
Disk Service.
• The storage device manufacturer must supply a software
component called a VDS hardware provider, which you
install on the computer, that will manage the device.
Summary
• Storage Explorer is an MMC console that provides
information about SAN resources and enables
administrators to perform a variety of
management tasks.