What`s New with Storage?
What’s New with Storage?
By Greg Schulz
article looks at storage technologies and trends that
impact mainframe, UNIX, and Microsoft Windows server
environments. Storage deployment continues to grow with no sign of
capacity usage requirements decreasing. The need for more storage
capacity and data protection can be traced to factors such as:
THIS
Applications continue to utilize and generate larger amounts
of data.
More structured and non-structured data is being digitally born.
Data is being kept for longer periods of time for regulatory
compliance.
Duplicate copies of data are being made and kept for longer
periods of time.
Hot storage topics include:
Information Lifecycle Management (ILM) for data and
storage management.
Data classification and creation of meta-databases to support
ILM initiatives.
Tiered data storage to support applicable business needs
and requirements.
Disk based backup as an alternative and/or a supplement to
magnetic tape.
Network Attached Storage (NAS) and Content Addressable
Storage (CAS).
NAS gateways to provide file access services of SAN
shared storage.
Wide Area File Services for improved remote data access
and protection.
Server, storage, and network based virtualization and
storage services.
Storage Resource Management (SRM) tools and
management software.
Technical Support | March 2005
Improvements to storage interfaces and protocols including:
Storage over IP (iSCSI & NAS) and distance enablement
(iFCP & FCIP).
Storage over SONET/SDH optical carrier (OC-3, OC-12,
OC-48) networks.
1Gb, 2Gb, and now 4Gb Fibre Channel with roadmap for
future 8Gb.
10Gb Ethernet and 10Gb Fibre Channel for use in backbone
networks.
Multi-protocol routers for distance, protocol conversion, and
segmentation.
A major premise of ILM (Information
Lifecycle Management) is to align the
appropriate storage technology to
applicable application and service
requirement need.
TIERED STORAGE
A major premise of ILM(Information Lifecycle Management) is to
align the appropriate storage technology to applicable application and
service requirement need. Tiered storage includes different classes of
data storage mediums (disk, tape, and optical technology), access
methods, interfaces, and protection schemes. Tiered storage is not a
new concept, particularly for enterprise and mainframe environments.
In its basic form, tiered storage includes magnetic disk for on-line and
magnetic tape for off-line data storage and protection.
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FIGURE 1 shows an example of a tiered storage environment that
encompasses different tiers for different applications and functions.
Server tiers ranging from IBM Mainframes to high-end, mid-range,
and entry level UNIX, Lintel, and Wintel type servers support application processing. These servers utilize block, file, or object based
access to storage resources using storage interfaces and protocols
including ESCON and FICON for IBM Mainframes. There are multiple methods for accessing storage (TABLE 1) including object, file, and
block based.
STORAGE OPTIONS
A storage platform option for mixed open systems and mainframe
attachment is cache centric enterprise class storage subsystems. For
open systems environments, distributed and modular storage subsystems are commonly deployed supporting block, file, and mixed access.
Clustered storage using tightly coupled and loosely coupled public and
proprietary interconnects are gaining popularity for scaling storage
resources. Most storage subsystems support one or more levels of
RAID data protection along with local and remote data mirroring.
Recent storage enhancements include support for partitioning of storage resources on storage subsystems and storage switches. An example
is the Hitachi TagmaStor Universal Storage Processor (USP) that can
partition storage devices, ports, and cache. Another example is the IBM
DS8000 that leverages the hypervisor function of the PowerPC processor architecture to create storage partitions (also known as logical
domains). The logical domains in the IBM DS8000 initially are
deployed to function as a storage subsystem however in the future they
could support other applications such as volume managers; SAN file
systems, and data protection software. Examples of switches with partitions include current generation ones from CNT and McData.
The disk drive market divides disks into three general categories:
consumer, desktop and enterprise. These, in turn, can be subdivided
further. All SATA disk drives are not the same in that there are desktop and enterprise class SATA disk drives. Enterprise class SATA
disk drives have advanced features including native command queuing (NCQ), vibration dampening, performance enhancements and
improved mean time between failures (MBTF) reliability. With initial deployments targeted for servers (blade and traditional), 2.5”
Serial Attached SCSI (SAS) disk drives will eventually find their
way into high-density storage arrays. In addition to SAS as a new
storage interface, SATA, Fibre Channel, and SCSI disk drives will
continue to be deployed for the foreseeable future. TABLE 2 shows
magnetic disk drive options characteristics and where they fit in a
tiered storage environment.
Another storage component for tiered storage is the storage and network interface and protocols that are used for attaching storage
resources. This includes server to storage interfaces and protocols
along with storage to storage for local and remote mirroring and data
migration. TABLE 3 shows various storage interfaces options for accessing storage resources.
The decision of how many storage tiers (or classes of storage) to
establish depends on how complicated you want to get. Keep in mind
the more classes and storage tiers that you establish, the more you
will have to manage. The idea behind stabling storage tiers is to help
address management by not treating all data the same. Find a balance
between too many storage tiers and treating all data the same that
results in more data being backed up and managed. A simple guide
TABLE 1: STORAGE ACCESS CHARACTERISTICS AND TYPICAL APPLICATIONS
Object
Based
(CAS)
File Based
(NAS)
Block
Based
Characteristics
Content address storage (CAS) based on
unique object identifier to reduce duplicate
data. Write Once Read Many (WORM)
technology may be incorporated for data
retention.
File based access and data sharing using IP
based networks. Some protocols include
Network File System (NFS) and Common
Internet File System (CIFS). Implemented on
general purpose servers, appliances with
dedicated storage, and via gateways using
shared SAN storage.
Low latency high performance data access
mechanisms. Fundamental method used by
other access methods to perform I/O to
storage devices.
Typical Applications
Fixed content and data
retention including medical
imaging, and financial
archiving for compliance and
regulatory needs.
Databases and E-mail with
low to moderate I/O and
performance needs as well as
web hosting and file serving
and data sharing across
multiple server and operating
systems.
I/O intensive applications
including databases, file
systems, OLTP, imaging,
large E-Mail systems.
TABLE 2: STORAGE OPTION APPLICATIONS
Drive Type
Fibre Channel
(FC)
SAS
SATA
Parallel SCSI
Characteristics
Well suited for online networked
(SAN & NAS) and direct attached
storage with good scalability and
performance.
High availability with good
performance for random reads for
on-line storage environments.
Near-line, secondary storage for
enterprise and primary storage for
entry level environments. Good
sequential read performance with
lower availability compared to
enterprise class storage.
High availability with good
performance for random reads for
on-line storage environments.
Comments
Well suited for mission critical
and high performance
applications in mid-range and
enterprise environments.
Good scalability, availability and
performance similar to FC
enterprise class disks with
affordably of SATA.
Low cost high capacity storage
not well suited for I/O
(performance) intensive
environments. Compatible with
SAS interfaces and controllers.
Good scalability, availability, and
performance for mid-range and
enterprise environments. Being
replaced by FC and SAS storage.
TABLE 3: STORAGE INTERFACE AND PROTOCOL OPTIONS
Protocol or Interface
ATA/IDE
ESCON (FC-SB)
Ethernet
FCIP
Fibre Channel
FICON
(FC-SB-2)
iFCP
Infiniband
iSCSI
NAS Gateway
PCI
PCI-Express
PCI-X
SAS
SATA
SCSI
SCSI Fibre Channel
Protocol (FCP)
UltraSCSI
Characteristics
Parallel electrical signaling traditionally used on PCs.
Mainframe interface that operates in half duplex at 18MB/sec.
Open standard networking interface supporting speeds from
10Mb/sec to 10,000Mb/sec (10Gb).
Protocol for spanning distances.
Open storage interface supports upper level protocols including
FCP, FICON, and TCP/IP among others at speeds of 1Gb, 2Gb,
4Gb, and 10Gb/sec over various distances and network topologies.
Mainframe protocol on Fibre Channel that supports full duplex
speeds of 400MByte/sec (2Gb) over extended distances.
Gateway protocol for distance and segmenting FC SANs.
Low latency interconnect that supports direct memory to memory
data transfers, SCSI command set, and TCP/IP.
SCSI command set on TCP/IP for block data access over IP.
While not a storage interface or protocol, NAS gateways are gaining
popularity to enable block SAN storage resources to be accessed by
IP network based servers.
Server host bus interface for attachment of peripherals including
Ethernet, Fibre Channel, SCSI, and Infiniband.
High speed server bus interface for attachment of Infiniband,
Ethernet, and Fibre Channel adapters.
Enhanced and faster version of traditional PCI interface.
Serial attached SCSI signaling to replace parallel SCSI.
Serial ATA signaling used for high capacity storage access.
Physical interface and command set.
SCSI command set on Fibre Channel for open systems block based
access commonly called Fibre Channel SAN.
Parallel electrical signaling using SCSI command set.
is to establish N+1 storage tiers where you have “N” tiers of on-line
or near-line storage and one off-line. Note that off-line does not have
to be magnetic tape, it could be optical or magnetic disk. TABLE 4
shows storage interfaces and devices along with future trend for the
next 1-3 years.
STORAGE VIRTUALIZATION SERVICES
Virtualization provides transparent access and abstraction of
resources as well as facilitates transition to new technology, and
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Technical Support | March 2005
improves and enhances management without adding workload.
Storage virtualization services can be implemented on host servers
using volume managers, storage subsystems, and network based
switches and appliances. Storage virtualization and services functions include:
Storage management and configuration.
Isolation of heterogeneous components (hardware and software).
RAID and data protection capabilities.
Heterogeneous mirroring and replication locally and
over distance.
LUN and Volume management including storage pooling and
aggregation.
Protocol conversion and gateway functions including file
(NAS) access.
Security including encryption and authentication.
Data migration and movement tools to support tiered storage.
STORAGE TRENDS AND TIPS
Workstation and
PC, Entry Level
NAS
Current
Storage
Interface
Disk and
Media
Type
Future
Storage
Interface
Disk and
Media
Type
Some general storage related trends and tips include:
TABLE 4: STORAGE INTERFACE AND DISK OPTIONS USAGE AND TRENDS
ILM is a process and paradigm approach to data and information
management as opposed to a specific product however there are
hardware, software, and network solutions that help support an
ILM enabled infrastructure.
Magnetic tape continues to be enhanced (performance,
capacity, reliability, lower cost) and is not dead, as some would
have you believe.
Magnetic disk is being used on an increasing basis for data
protection and functions that have traditionally been handled by
magnetic tape.
Storage Management Initiative Specification (SMIS) is being
deployed by hardware and software vendors as a management
interface technology.
Faster storage interfaces including PCI-Express and PCI-X host
adapters are appearing on servers to utilize faster CPUs, storage,
and network interfaces.
Wide Area File Services (WAFS) enabling remote storage to be
accessed more efficiently, including management for data
protection at faster speeds and improved network utilization over
WAN interfaces.
Understand and classify your applications and data to align to
properly tiered storage, tiered storage access, and tiered data
protection level.
The golden rule of storage virtualization is that who ever
controls the meta data, or storage services management software,
controls the vendor lock-in.
Chipsets,
ATA/SATA &
SCSI adapters,
Ethernet NICs
(iSCSI initiator
and NAS over IP)
ATA & SATA
(5,400 & 7,200
RPM) single
ported.
Chipsets, SAS
Adapters
ATA & SATA
(5,400 to
7,200RPM), SAS
10K and 15K,
single ported
Servers, Blade
Servers, Direct
Attached
Storage
Chipsets, RAID
on mother boards
(ROMB), blades
with embedded
disks,
ATA/SATA,
SCSI, FC
adapters, Ethernet
NICs (iSCSI &
NAS)
ATA & SATA
(5,400 &
7,200RPM),
SCSI single and
dual ported.
Chipsets, ROMB
Adapters,
Ethernet (iSCSI
& NAS)
SATA (5,400 &
7,200RPM), SAS
(10K & 15K
RPM) single and
dual ported
Primary
Storage,
network
attached via
SAN or NAS for
Enterprise and
Midrange use
Secondary,
Near-line and
Offline storage
SCSI,
FC/FICON,
ESCON, SATA,
Ethernet for
iSCSI and IP
based NAS.
SCSI,
FC/FICON,
ESCON, SATA,
Ethernet for
iSCSI and IP
based NAS.
ATA, SATA,
SCSI, FC various
speeds up to 15K
and capacities
from 18GB up to
400GB. Single &
dual port.
Magnetic Tape
Optical Disk
Magnetic Disk
ATA, SATA,
SCSI, FC larger
capacity disk
drives
iSCSI/Ethernet,
FC/FICON, SAS
iSCSI/Ethernet,
FC/FICON, SAS
SAS and FC disk
drives (10K &
15K RPM),
single, dual, quad
ported
Magnetic Tape
Optical Disk
Magnetic Disk
SATA, SAS and
FC disk drives
(10K & 15K
RPM), single,
dual, quad ported
FIGURE 1: TIERED STORAGE, ACCESS, AND DATA PROTECTION
(FUD). To fully leverage buying opportunities, you need to have a plan
and be aware of current technology options. You can learn more about
buying and acquisition, including free evaluation criteria workbooks, at
the Evaluator Group website (www.evaluatorgroup.com/workbook).
SUMMARY
It is a storage buyer’s market when it comes to storage, particularly
hardware oriented acquisitions. There are many options, however, there
is also a large amount of vendor hype and fear uncertainty and doubt
Technical Support | March 2005
NaSPA member Greg Schulz is the author of the book “Resilient Storage
Networks” (Elsevier Books) ISBN 1555583113 and a senior analyst with the
Evaluator Group.You can learn more at www.evaluatorgroup.com/book.
©2005 Technical Enterprises, Inc. Reproduction of this document without permission is prohibited.
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