Transcript storage area network (SAN)

Managing Storage
Lesson 3
Objectives
Storage
• While you need sufficient processing power
and a sufficient amount of RAM, you will also
most likely need a large amount of storage.
• Although simple servers usually require that
you install Windows Server on a local IDE
(parallel and serial) or SCSI hard drive, more
complex systems may use a form of RAID or
attached remote computer storage devices
such as a storage area network (SAN) or
network attached storage (NAS).
RAID
• Because most drives are half-electronic and halfmechanical devices, you can connect multiple drives to
special controllers to provide data production, system
reliability, and better performance.
• A redundant array of independent disks (RAID) uses
two or more drives in combination to create a faulttolerant system that protects against physical hard
drive failure and increases hard drive performance.
• A RAID can be accomplished with either hardware or
software and is usually used with network servers.
RAID 0
• RAID 0 stripes data across all drives.
• With striping, all available hard drives are
combined into a single large virtual file system,
with the file system’s blocks arrayed so that they
are spread evenly across all the drives.
• Unfortunately, with RAID 0, there is no parity
control or fault tolerance; therefore, it is not a true
form of RAID.
• However, RAID 0 does have several advantages
because it offers increased performance through
load balancing.
RAID 1
• RAID 1 is sometimes known as disk mirroring.
• Disk mirroring copies a disk or partition onto a
second hard drive. Specifically, as information is
written, it is written to both hard drives
simultaneously.
• If one of the hard drives fails, the PC will still
function because it can access the other hard
drive.
– Then, should you later replace the failed drive,
data will be copied from the remaining good
drive to the new drive.
RAID 5
• RAID 5, which is similar to striping, except the space
equivalent to one of the hard drives is used for parity
(error correction) to provide fault tolerance.
• To increase performance, the error correction function
is spread across all hard drives in the array to avoid
having one drive doing all the work in calculating the
parity bits.
• Therefore if one drive fails, you can still continue
working because parity calculations with the remaining
drives will fill in any missing data.
• Later, when the failed drive is replaced, the missing
information will be rebuilt.
Hybrid RAID
• There are two other forms of RAID worth
mentioning, both of which are considered
hybrid or nested RAIDs:
– RAID 1+0 is a mirrored dataset (RAID 1),
which is then striped (RAID 0).
– RAID 0+1 is a striped dataset (RAID 0), which
is then mirrored (RAID 1).
Hot Spare
• A hot spare is much like it sounds. When
drives need to be fault tolerant, you can
combine a hot spare drive with a RAID.
• Then, if a drive fails, the system will
automatically grab the hot spare drive to
replace the failed drive and rebuild or
restore the missing data.
Network Attached Storage
• Network attached storage (NAS) is a file-level
data storage device that is connected to a
computer network to provide shared drives
or folders, usually using SMB/CIFS.
• NAS devices usually contain multiple drives
in a form of RAID for fault tolerance and are
managed usually using a web interface.
Storage Area Network
• A storage area network (SAN) is an architecture
used for disk arrays, tape libraries, and optical
jukeboxes to appear as locally attached drives on a
server.
• A SAN always uses some form of RAID and other
technology to make the system redundant against
drive failure and to offer high performance.
• SANs also usually contain spare drives.
• To provide a high level of data throughput, SANs
use the SCSI protocol and either iSCSI or Fibre
Channel interface.
Host Bus Adapter
• A host adapter, sometimes referred to as
host bus adapter (HBA), connects a host
system such as a computer to a network or
storage device.
• It is primarily used to refer to connecting
SCSI, Fibre Channel, and eSATA devices
LUNs
• Logical unit numbers (usually referred to as
LUNs) allow a SAN to break its storage down
into manageable pieces, which are then
assigned to one or more servers in the SAN.
• It is a logical reference that can comprise a
disk, a section of a disk, a whole disk array, or
a section of a disk array.
• LUNs serve as logical identifiers through
which you can assign access and control
privileges.
Fibre Channel
• Optic fiber cabling offers higher bandwidths and
can be used over longer distances than copper
cabling because signals travel with less loss and
are immune to electromagnetic interference.
• Fibre Channel or FC is a gigabit-speed technology
primarily used for storage networking.
• It uses a Fibre Channel Protocol (FCP) as its
transport protocol, which allows SCSI commands to
be issued over Fibre Channel.
iSCSI
• Internet Small Computing System Interface or iSCSI
is an Internet Protocol (IP)-based storage networking
standard for linking data storage facilities.
• iSCSI allows clients to send SCSI commands over a
TCP/IP network using TCP port 3260.
• Similar to Fibre Channel, iSCSI can communicate
using Gigabit Ethernet or Fibre, and it can connect a
SAN to multiple servers over a distance.
• Although iSCSI uses normal network technology to
communicate, the network adaptor must be
dedicated to iSCSI.
iSCSI Initiator Software
Storage Explorer
• Windows Server 2008 includes Storage Explorer
and Storage Manager for SANs to manage Fibre
Channel, iSCSI fabrics, and LUNs.
• Storage Explorer allows you to view and manage
the Fibre Channel and iSCSI fabrics that are
available in your SAN.
• Storage Explorer can display detailed information
about servers connected to the SAN, as well as
components in the fabrics such as host bus
adapters (HBAs), Fibre Channel switches, and iSCSI
initiators and targets.
Storage Explorer
Disk Structure
• Before you use a disk, you must prepare the
disk for usage by creating partitions or
volumes and formatting the disk.
• When you want to use a disk in Windows,
you have several choices to make:
– Disk partitioning style
– Disk type
– Type of volume
– File system
Partitioning
• Partitioning is defining and dividing a physical or
virtual disk into logical volumes called partitions.
• Each partition functions as if it were a separate
disk drive, which can be assigned a drive letter.
• To keep track of how a disk is divided, the disk
uses a partition table.
• Formatting a disk prepares the volume’s file
system by creating a file allocation table to keep
track of the files and folders on the volume.
Partitioning Style
• Partitioning style refers to the method that
Windows uses to organize partitions on a
disk.
• Windows Server 2008 supports two types of
disk partitioning styles:
– Master Boot Record (MBR)
– GUID Partition Table (GPT)
Windows Hard Disk Storage
• Most versions of Windows servers—including
Windows Server 2008—support two types of
hard disk storage
– Basic disks are the traditional disk type,
– Dynamic disks offer software-based RAID
and the ability to resize volumes without
rebooting.
Dynamic Disks
• Dynamic disks support five types of volumes:
– Simple volume
– Spanned volume
– Striped volume
– Mirrored volume
– RAID-5 volume
File System
• A file system is a method of storing and
organizing computer files and the data they
contain to make it easy to find and access
this information.
• A file system also maintains the physical
location of the files so that you can find and
access the files in the future.
• Windows Server 2008 supports FAT16,
FAT32, and NTFS file systems on hard
drives.
FAT16 and FAT32
• FAT16, sometimes referred to generically as File
Allocation Table (FAT), is a simple file system that
uses minimum memory and was even used with
DOS.
– Unfortunately, FAT can only support volumes up
to 2 GB.
• FAT32 was released with the second major release
of Windows 95. Although this file system can
support larger drives, today’s Windows versions
support volumes only up to 32 GB.
NTFS File System
• As mentioned earlier, New Technology File System
(NTFS) is the preferred file system, largely because
it supports both a much larger hard disk (up to 16
exabytes) and long file names.
• NTFS is more fault tolerant than previous file
systems used in Windows because it uses
journaling to make sure that disk transactions are
written properly before they can be recognized.
• NTFS offers better security through permissions
and encryption.
Disk Management
• The main disk management tool in Windows
Server 2008 is the MMC snap-in called Disk
Management, which is also part of the
Computer and Management consoles.
• In addition, you can use a diskpart.exe and
the Format command to partition and format
a drive, as well as Windows Explorer to
format a drive.
Disk Management
Initializing a Disk
Converting to a Dynamic Disk
Creating a Simple Volume
Assigning Drive Letter or Path
Formatting Drive
Extending Volume
Summary
• Today’s drives are either IDE drives (mostly found
on consumer computers) or SCSI drives (mostly
found in servers).
• A redundant array of independent disks (RAID)
uses two or more drives in combination to create a
fault-tolerant system that protects against physical
hard drive failure and increase hard drive
performance.
Summary
• Network attached storage (NAS) is a file-level data
storage device that is connected to a computer
network to provide shared drives or folders, usually
using SMB.
• A storage area network (SAN) is an architecture
used for disk arrays, tape libraries, and optical
jukeboxes to appear as locally attached drives on a
server.
• A host adapter, sometimes referred to as host bus
adapter (HBA), connects a host system such as a
computer to a network or storage devices.
Summary
• A file system is a method of storing and organizing
computer files and the data they contain to make it
easy to find and access this information. A file system
also maintains the physical location of the files so you
can find and access the files in the future.
• Currently, NTFS is the preferred file system, in part
because it supports much larger hard disks (up to 16
exabytes) and long filenames.
• NTFS is a journaling file system that makes sure a disk
transaction is written properly before it is recognized.
• NTFS offers better security through permissions and
encryption.