Storage Basics and Application Environments Overview

Storage Basics and
Application Environments

1. What Is Storage?
1 Huawei Confidential
• Storage Concepts
• Storage in Data Centers
• Storage Evolution
• Block Storage
• File Storage
• Object Storage
2. WhatAre the Basic Concepts of Storage Hardware (L2)?
• Disks (NVMe SCM)
• DiskArrays
• Controllers
• Controller Enclosures
• Disk Enclosures
• High-Density Enclosures
• I/O Modules and HBAs
3. WhatAre the Basic Concepts of Storage Protocols?
• SCSI
• NVMe
• iSCSI
• Fibre Channel
• SAS
4. What Are the Other Basic StorageConcepts?
• RAID
• LUN
• Multipathing
• File System
• Local File System
• Network File System
• CIFS
• NFS
• Storage Performance Indicators
5. WhatAre the Basic Concepts of Data Protection?
• RPO and RTO
• Backup
• Disaster Recovery
• Snapshot
• Remote Replication
• Mirroring
• Clone
Contents

What Is Storage?
CDs, DVDs, Zip drives, tapes, disks ...
1. Storage hardware (disk arrays, controllers, disk enclosures, and tape libraries)
2. Storage software (management software, snapshot, replication, and multipathing software)
3. Storage networks (HBAs, Fibre Channel switches, as well as Fibre Channel and SAS cables)
4. Storage solutions (centralized storage, archiving, backup, and disaster recovery)
Disk array
Fibre
Channel
link
Controller
Fibre
Channel
switch
— Storage Is the Media for Storing and Protecting Data
 Storage in a narrow sense  Storage in a broad sense
Server
Multipathing
software

Storage Concepts
Storage is to save data to certain storage media in a reasonable, secure, and effective manner to meet requirements of
different application environments and ensure effective accesses to the data. Specifically:
1. Storage is physical media for temporary or long-term datastorage.
2. Storage is a method or behavior for ensuring data integrity and security. Storage combines the two aspects to provide
customers with a data storage solution.
Core of storage — data
 Structured data: Refers to data stored in databases and logically represented by bidimensional table structures.
Structured data includes data in databases such as SQL, Oracle, and DB2.
 Unstructured data: Refers to data that cannot be logically represented by bidimensional table structures. Unstructured
data includes documents, texts, pictures, XML, HTML, images, as well as audio and video information in all formats.
Storage capacity increases mainly due to the rapid growth of unstructured data.
Major storage performance indicators
 IOPS: Indicates the number of I/Os processed by a storage array per second. Generally, the performance ofrandom
reads and writes of small files such as database files depends on the IOPS.
 Bandwidth (MB/s): Indicates the maximum output bandwidth that a storage array can provide per second. The
maximum bandwidth of a storage array generally refers to the sequential read bandwidth of the cache. The
performance of continuous reads and writes of large files such as videos depends on the bandwidth.

Storage in Data Centers
Server hardware
Storage
Network
Server
Virtualization
Application
Runtime library
Security and integration
Database
OceanStor
9000
Dorado 5000V6
Dorado 6000V6
FusionStorage
OceanStor
2200 V3 or
2600 V3
OceanStor 18500V5
or 18800 V5
OceanStor
6800 V5
OceanStor
5000 series V5
(mid-range)
Dorado 8000 V6 or
18000 V6

Storage Evolution
Disk
CPU
Arm
Server
SCSI card
Controller
Server
CPU
Arm
Disk
Disks in aserver
Just a Bunch of Disk (JBOD)
CPU Server
Arm
Disk
RAID SCSI card
External disk array(DAS) Smart disk array(DAS)
Limitations
• Disks become the system performance
bottleneck.
• The number of disk slots is limited,
thereby providing limitedcapacity.
• Data is stored on single disks, and data
storage is less reliable than expected.
• Storage space utilization islow.
• Data is scattered in local storage
systems.
JBOD logically connects several
physical disks to increase capacity. It
does not provide data protection.
A controller provides RAID and large-capacity cache,
enables the disk array to have multiple functions, and
is equipped with dedicated management software.
Resolved issues
• Disks become the system performance
bottleneck.
• Data is stored on single disks, and data
storage is less reliable than expected.
• Storage space utilization islow.
• Data is scattered in local storage
systems.
Resolved issues
• Data is stored on single disks, and
data storage is less reliable than
expected.
Resolved issues
• Disks become the system performance bottleneck.
• The number of disk slots is limited, providing a
small capacity.
• Data is stored on single disks, and data storage is
less reliable than expected.
SAN
NAS
SAN
File system File system
File system
RAID
RAID
LAN
Application
server
Application
server
Multiple
application
servers

File storage
• Advantages: easy management and
interconnection with applications
• Disadvantages: support for expansion but with
many restrictions
• Application scenarios: enterprises'internal
application integration and filesharing
NFS or CIFS
...
File system  File storage is used to store unstructured data.
Professional file systems are added to block storage
devices to implement file sharing.
 More generally, file storage is used to store data,
such as data in the TV station industry, including
videos, audio data, images, films (finance), oil
exploration data, biomedicine data, and HPC
computing data (big data).
File Storage

...
iSCSI or Fibre Channel
Protocol
layer
Storage
layer
Block storage
• Advantages: direct access, minimized overhead,and
highest efficiency
• Disadvantages: highest cost and poorscalability
• Application scenarios: enterprise databases, such as
Oracle
Block Storage
 Block storage is used to store structured data,
that is, data is directly read and written by
reading or writing one or more addresses from or
into storage space.
 More generally, block storage stores data of
databases such as SAP and Oracle, common
office mails (Exchange), tables, and financial
data.

Object storage
• Flat structure and nearly unlimitedcapacity expansion
• More intelligent self-management
• Standard Internet protocols and cross-region transmission
capabilities
• Application scenarios: Internet-oriented storage, archiving,
and backup
...
Object
Object
storage
Object
Key
Metadata
Data
Customized
metadata
HTTP, REST, SOAP, orS3
Object Object
Object
Object
Object Storage
 Object storage, also known as object-based
storage (OBS), is a network storage
architecture. The differences between OBS
and block storage or file storage lie in the
interfaces (S3 interfaces) provided by OBS.
OBS only generates an ID for the metadata of
stored data and stores the ID, regardless of
the data type.
 This storage architecture is mainly used in the
application scenarios that have low
requirements on performance but high
requirements on capacity. It is mainly used to
meet customers' requirements on large
capacity and low price. The application
scenarios include public cloud, Internet, and
space leasing.

What Are the Basic Concepts of
Storage Hardware (L2)?

 A hard disk drive (HDD) is a traditional hard disk. It consists
of a platter, a head, a platter rotating shaft, a control motor, a
head controller, a data converter, interfaces, and cache.
 A solid-state disk or solid-state drive (SSD) is also called an
electronic disk or a solid-state electronic disk. Different from
HDDs that use mechanical parts such as disk bodies, heads,
and motors, SSDs are composed of control chips and
storage chips (flash or DRAM chips). In other words, SSDs
are made of solid-state electronic storage chip arrays.
Disks

SSDs VS. HDDs
SSD HDD
Storage media Flash chip Magnetic disk
Shockproof and drop resistance High Low
Data storage speed High: hundreds of MB/s Low: dozens of MB/s
Power consumption Low High
Weight Light Heavy
Noise None Yes
Price High: several yuan (RMB) perGB Low: several jiao (RMB) per GB
Capacity Hundreds of GB to several TB Several TB
Service life Short (about several years) Relatively long

Disk types
Disk diameters
5.25-inch
3.5-inch
2.5-inch
1.8-inch
Media
HDD
SSD
Interface protocols
ATA, IDE
SATA, NL-SAS
SCSI
SAS
Fibre Channel
Functions
Desktop level
Monitoringlevel
Enterprise level
Disk Types
Desktop-level disks are mainly used for home applications, such as desktop
PCs and laptops. Enterprise-level disks are designed for enterprise
applications, such as servers, disk arrays, and graphics workstations.
Mainstream disk types
HDDs: SATA, NL-SAS, andSAS
SSDs: SATA, SAS, andNVMe

Disk Types — Serial ATA (SATA)
Advantages
1. SATA is a serial bus interface protocol. During data transmission, the data and signal cables
are used independently, and the embedded clock frequency signal is used. Its rate can reach
30 times of the Parallel ATA(PATA).
2. Instead of simple PATAimprovement, the bus structure is brand new.
3. Control information is scattered in data and transmitted by using a predefined bit.
4. One path is used to transmit data, and the other is used to return a response.
5. SARA has higher anti-interference capabilities and faster speed than PATA. The installation
is easier and the number of cables used in the chassis is reduced.
6. The performance of single-thread tasks is good.
Disadvantages
1. SATA, designed for entry-level applications, is not as powerful as SCSI in terms of big data
throughput or multi-thread transmission.
2. When multiple threads are reading data, the head of a disk swings back and forth, causing
the disk to be overheated.

Disk Types — Serial Attached SCSI (SAS)
1. SCSI is a storage interface protocol specially designed for small computer systems. 50-pin
ports are used. The appearance of a 50-pin port is similar to that of a common disk port.
The SCSI disks support connections to various devices. In addition, each SCSI disk has an
independent chip for data processing. The CPU usage is low, the bandwidth can reach 320
MB/s, and the stability is good.
2. SAS is a disk connection technology that integrates the advantages of the parallel SCSI
and serial connection technologies.
3. SAS is a point-to-point, full-duplex, and dual-port interface.
4. SAS is compatible with SATA, meeting high-performance requirements of enterprises,
achieving interoperability with SATA, and bringing unprecedented flexibility and benefits to
enterprises.
5. SAS features high performance, high reliability, and powerful scalability.
The serial technology is also used, which is better than SCSI in transmission rate and anti-
interference. However, the price is higher.

Disk Types — Near-Line SAS (NL-SAS)
1. NL-SAS disks integrate SAS interfaces and SATA disks. In other words, NL-SAS disks
refer to SATA disks with SAS interfaces and near-SAS performance.
2. Near-line storage is oriented to applications between online storage and offline storage.
Data that is not frequently used or seldom accessed is stored on the storage devices of
which performance is relatively low. However, these devices must provide fast
addressing capabilities and a high transmission rate.

Disk Types — SSDs
SSD hardware structure
DDR
• No high-speed rotational components, high
performance, and low power consumption
• Concurrent multiple channels, allowing time-
division multiplexing for flash granules in a channel
• TCQ and NCQ, responding to multipleI/O
requests in one response
• Typical response time of less than 0.1ms
SAS port
Flash
6 Gbit/s Multi-channel
concurrence
SSD controller
SSD architecture
Backup
power supply

Indicator SATA HDD SAS HDD NL-SAS HDD SSD
Rotational speed(rpm) 7200 15,000 or 10,000 7200 N/A
Capacity (TB) 4, 6, 8, 10, or 14 1.2, 1.8, or 2.4 4, 6, 8, 10, or 14 1.92, 3.84, or 7.68
MTBF (h) 1,200,000 1,600,000 1,200,000 2,000,000
Remarks
Being developed from
ATA disks, SATA 2.0
supports 300 MB/s data
transfer, and SATA 3.0
supports up to 600MB/s
data transfer.
The annual failure rateof
SATA disks is about2%.
SAS disks are designedto
meet enterprises' high
performancerequirements
and are compatible with
SATA disks. The
transmission rate ranges
from 3.0 Gbit/s to 6.0
Gbit/s, and will be
increased to 12.0 Gbit/sin
the future.
The annual failure rateof
SAS disks is less than2%.
NL-SAS disks are enterprise-
class SATA drives with SAS
interfaces. They are applicableto
tiered storage in a disk array,
which simplifies the design ofthe
disk array.
The annual failure rate ofNL-
SAS disks is about2%.
An SSD is made up of a solid-state
electronic storage chip array. AnSSD
consists of a control unit and a
storage unit (flash and DRAM chips).
SSD is the same as the common
disks in the regulations and definition
of interfaces, functions,usage, as well
as the exterior andsize.
• A disk interface is a component connecting a disk and a host, and is used to transmit data between the disk cache
and host memory.
• Different disk interfaces determine the connection speed between disksand computers, which affects the program
running speed and system performance.
Comparison of Mainstream Disk Types

Basic Concepts Related to RAID
RAID 0 Known as a stripe set or striped volume, it splits dataevenly
across two or more disks, without parity information,
redundancy, or fault tolerance.
RAID 1 It consists of an exact copy (or mirror) of a set of data on two
or more disks; a classic RAID 1 mirrored pair contains two
disks. This configuration offers no parity, striping, or spanning
of disk space across multiple disks, since the data ismirrored
on all disks belonging to the array, and the array can only be
as big as the smallest memberdisk.
RAID 3 It is rarely used in practice. It consists of byte-level striping
with a dedicated paritydisk.
RAID 5 It consists of block-level striping with distributedparity.
RAID 6 RAID 6 extends RAID 5 by adding another parity block; thus, it
uses block-level striping with two parity blocks distributed
across all member disks.
RAID 0+1 RAID 01, also called RAID 0+1, is a RAID level using a
mirror of stripes, achieving both replication and sharing
of data between disks.
RAID 10 RAID 10, also called RAID 1+0 and sometimes RAID
1&0, is similar to RAID 01 with an exception that two
used standard RAID levels are layered in the opposite
order; thus, RAID 10 is a stripe ofmirrors.
RAID 50 RAID 50, also called RAID 5+0, combines the straight
block-level striping of RAID 0 with the distributed parity
of RAID 5.
Redundant Array of Inexpensive Disks or Drives, or Redundant Array of Independent Disks (RAID) is a data storage
virtualization technology that combines multiple physical disk drive components into one or more logical units for the
purposes of data redundancy, performance improvement, or both.
Two different RAID levels can be combined to form anew
RAID level.
RAID is classified into different RAID levelsbased on
the combination methods.

SCM — Next-Generation Storage Media
Storage Class Memory (SCM) is a new storage
medium popular in the industry. SCM is similar to
storage in its persistence and to memory in its
byte-level access.
The SCM SSD, which uses NVMe block interface
and is compatible with the native architecture, is
the primary application form of SCM. Optane
P4800X series launched by Intel is an example.
This product has little impact on the system
architecture but provides better performance than
that of flash SSDs. In addition, SCM SSDs do not
require garbage collection, which prevents
performance deterioration similar to that of NAND
SSD after long-time running, and curbs latency at
an appropriate level. This type of storage products
is springing up in the industry, and Huawei is also
working on the R&D of relevant products.
High-performance SSDs provide the following
application forms in a storage system:
 Metadata cache: As metadata cache of AFA, SCM
SSDs work with the DRAM to build a memory +
SCM SSD two-tier cache, which avoids
bottlenecks in memory capacity and supports
larger user capacity with stable performance.
 Data cache: SCM SSDs serve as the acceleration
layer of user data and improves performance in
typical application scenarios.
 Main storage: SCM SSDs serve as the storage
layer of user data and provides a high-
performance storage system to meet the
performance requirements of some scenarios.

A disk array consists of multiple disks
and is used as a single disk. Data is
stored in different disks in striping mode.
When data is accessed, the related
disks in the disk array work together,
which greatly reduces the data access
time and improves the space utilization.
Disk Arrays

Controller enclosure Disk enclosure
=
+
Separation of the controller
enclosure and disk enclosure
Integration of controllers and
disk enclosure
Disk enclosure
Controller module
=
+
Disk array
Disk array
Disk Array Composition

The controllers are the brain of a storage array.
The main components of a controller are the
processor and cache. A controller implements
simple I/O operations and RAID management.
With the development of technologies,controllers
can provide various data management functions,
such as snapshot, mirroring, and replication.
Controllers

Controller Enclosures
Control module
Power module
BBU
Fan module
I/O module
Chassis

3.5-inch disk enclosure
 24 x 3.5-inch disks
 Support for mainstream SAS
disks, SATAdisks, and SSDs
 Independent power-on and
power-off for each disk
Expansion modules
 1 + 1 redundancy
 System power-on and
power-off through in-band
commands
Power modules
 2 + 2 redundancy
 90% power conversion
efficiency
Fan modules
 2 x (3 + 1) redundancy
 Energy-efficient heat
dissipation
 Granular fan speedcontrol
Disk Enclosures

High-Density Enclosures
 Huawei uses 4 U 75-slot disk enclosures as
high-density enclosures.
 A high-density enclosure featureslarge
capacity, high bandwidth, low power
consumption, and low TCO.
 It applies to scenarios, such as media assets,
archiving, and backup, where customers
require large capacity.

I/O Modules and HBAs
Common I/O Module Types

 8 Gbit/s Fibre Channel I/O module: 4 ports per
I/O module
 GE I/O module: 4 ports per I/O module
 10GE I/O module: 2 ports per I/O module
 4 x 6 Gbit/s SAS I/O module: 2 ports per I/O
module
4 Gbit/s Fibre Channel I/O module: 4 ports per
I/O module
 FCoE I/O module; TOE I/O module
 An I/O module connects a storage system to a server or switch for data transmission. The I/O
module includes field pluggable units with several interfaces.
 HBA is short for Host Bus Adapter. An HBA is a circuit board that enables a computer to provide I/O
processing and physical connections between a server and a storage device.
Common HBAs
 Fibre Channel card
 FCoE card
 10GE card
 GE card
 InfiniBand (IB) card

Storage Protocols?

Small Computer System Interface (SCSI) is
the most common method for connecting
storage devices to servers.
SCSI was first developed in 1979 and is an
interface technology for mid-range computers.
With the development of computer
technologies, SCSI is now completely
transplanted to ordinary PCs.
SCSI-3 is the basis of all storage protocols,
because all storage protocols use the SCSI
instruction set.
SCSI

Internet Small Computer System Interface
(iSCSI) is an Internet Protocol (IP)-based
storage networking standard for linking data
storage facilities. It provides block-level access
to storage devices by carrying SCSI
commands over a TCP/IP network.
Used over the IP-based SAN, the iSCSI
protocol provides quick, cost-effective, and
long-distance storage solutions.
iSCSI encapsulates SCSI commands into a
TCP or IP packet, enabling I/O data blocksto
be transferred over the IP network.
iSCSI

Fibre Channel is a high-speed data transfer protocol
providing in-order, lossless delivery of raw block data.
Fibre Channel is primarily used to connect computer data
storage to servers in storage area networks (SAN) in
commercial data centers. Fibre Channel networks form a
switched fabric because the switches in a network operate
in unison as one big switch. Fibre Channel typically runs
on optical fiber cables within and between data centers,
but can also run on copper cabling.
Fibre Channel is a high-performance serial connection
standard. The interface transmission rate can be 16 Gbit/s
or 32 Gbit/s. The transmission media can be copper cables
or optical fibers. The transmission distance is long and
multiple interconnection topologies are supported.
Fibre Channel

Serial Attached SCSI (SAS) is the serial
standard of the SCSI bus protocol.
SAS uses the serial technology to
achieve higher transmission rate and
better scalability, and is compatible with
SATAdisks.
The transmission rate of the SAS
reaches 6 Gbit/s and 12 Gbit/s, and the
SAS supports the full-duplex mode.
SAS

NVMe
1. NVMe is a controller interface standard developed for enterprises
and client systems that use PCIe SSDs.
2. It is not only a logical protocol interface, but also an instruction
standard and a specified protocol.
3. NVMe covers optimized controller register interfaces, command
sets, and I/O queue management.
4. NVMe features low latency, high IOPS, and low power
consumption.

What Are the Other Basic Storage
Concepts?

RAID
RAID 0
RAID 1
RAID 10
RAID 50
RAID 5
RAID 6
RAID MP
RAIDADG
RAID 5E
RAID DP
RAID 1E RAID 5EE
The term RAID was invented by David Patterson, Garth A. Gibson, and Randy Katz at
the University of California, Berkeley in 1987. It combines multiple independent physical
disks into a virtual logical disk using related algorithms to provide larger capacity, higher
performance, and better error tolerance capabilities.

One or multiple logical volumes can be created for RAID based on the specified
capacity. A logical volume is identified by logical unit number (LUN).
RAID 10 RAID 5
Logical volume Logical volume
One logical volume is created
on a physical volume.
Two logical volumes are created on a
physical volume.
LUN 1 LUN 2 LUN 3
LUN

 To prevent single points of
failure, the high-reliability system
provides redundancy backup for
devices that may encounter
single points of failure. Path
redundancy is also included.
 The multipathing technology can
be used to ensure reliable use of
redundant paths. This
technology automatically and
transparently transfers I/O flows
to other available paths, ensuring
effective and reliable
transmission of I/O flows.
Multipathing

File system: refers to a data structure and a
data management mode when files are
stored on disks.
Therefore, it is necessary to correlate
sectors so that data on disks can be
accessed. In other words, a logical data
storage structure must be established. Afile
system is used to establish such data
storage structure. Generally, the process of
creating file systems on disks is called
formatting.
File System

File systems and application programs are on a same server.
Storage silos
File system
Local file system
Applicationsystem
File system
Local file system
Applicationsystem
File system
Local file system
Applicationsystem
Storage
Storage Storage
Local File System

File system client
Applicationsystem
Storage
File system client
Applicationsystem
File system client
Applicationsystem
File system client
Applicationsystem
Network protocol
File system
server
NFS and CIFS are universal
network file systems. These
systems can be used to
implement file sharing
between heterogeneous
platforms.
Network File System

CIFS
The Common Internet File System (CIFS) is a mainstream
share file system developed by Microsoft for serving
heterogeneous platforms and is mainly applied in Windows.
Client systems use the TCP or IP protocol to request file
access services from server systems over a network.
CIFS share authentication provides two types of shared file
access permissions: user and Active Directory Server
(ADS).
The CIFS normal share means that the file system is shared
as a directory and all users can access the directory.
The CIFS homedir share is a file sharing mode providedby
file engines. The CIFS homedir share only allows a user to
access the directory named with the user name and each
user can only access a directory that belongs to the user's
directory.

NFS
Network File System (NFS) is a distributed file
system protocol.
It allows a user on a client computer to access
files over a computer network much like local
storage is accessed. NFS, like many other
protocols, builds on the Open Network
Computing Remote Procedure Call (ONC
RPC) system. The NFS is an open standard
defined in a Request for Comments (RFC),
allowing anyone to implement the protocol.

SPC is an internationally recognized
authoritative, third-party, and non-
profit storage performance test
organization. Currently, vendors in the
storage industry, such as Huawei,
IBM, HP, Sun, HDS, and Dell, are
important members of SPC. SPC-1 is
an industry-recognized storage
performance benchmark test standard
launched by SPC. SPC-1 simulates
database OLTP applications and
email system applications to measure
the IOPS of SAN storage systems.
Input/output operations per second
(IOPS), that is, read and write
operations (I/Os) per second, is a
performance index in evaluating the
random access performance of
databases.
The IOPS is a standard for
measuring the performance of a SAN
storage system. A larger IOPS
indicates better performance.
IOPS

SPEC is an international authoritative
organization for evaluating system
application performance. SPECsfs2008 is
a core benchmark released by SPEC for
file service applications. It measures the
file access throughput and response time
and provides a standard evaluation
method for comparing the performance of
file servers from different vendors. Nearly
20 mainstream NAS manufacturers have
verified the performance of core products
based on this benchmark.
OPS
Operations Per Second (OPS) is the
number of times that NFS and CIFS
are responded to per second. It is
mainly used in file system scenarios
to measure file access performance.
The OPS is a standard for measuring
the performance of a SAN storage
system. A larger OPS indicates better
performance.

Performance Indicators and Evaluation Methods of Storage Devices
Performance indicators
IOPS is the number of I/Os that can be processed by a storage device per second. It is used to measure the response
capability of a storage device. IOPS is the most important measurement indicator for a large number of small I/Os.
Bandwidth is also called throughput that indicates the total amount of data that can be processed per second. It is used to
measure the storage throughput. Bandwidth is useful for measuring large I/Os, especially for measuring the time required
for processing a large amount of data.
Bandwidth = IOPS x Average I/O size
Latency refers to the time consumed for processing I/Os. It is used to measure the processing speed of storage devices.
Latency is classified into host latency and storage latency. Storage latency refers to the period from the time when I/Os
arrive at the storage device to the time when the storage device returns a processing completion message to the host.
Host latency is the sum of the storage latency, link transmission time, and host queuing time. Users focus on the host
latency.
IOPS = Number of concurrent requests/Average latency
Performance evaluation
IOPS and bandwidth are the two most important indicators for performance evaluation.
The IOPS assessment focuses on the I/O sequence, cache hit ratio, and IOPS of a single disk. The major bottleneck of
the maximum IOPS of a storage system is the CPU processing capability.
The bandwidth assessment focuses on the I/O size, bandwidth of a single disk, and storage hardware bandwidth. For the
maximum bandwidth of a storage system, the major bottleneck is the front-end and back-end channel bandwidth and
mirroring bandwidth.

Data Protection?

Online application information is extracted to create one or more copies based oncertain
policies, and the copies are stored on preset storage media for recovery in case of an
online system fault.
Protectable faults Protection data types Types of backup media
Backup

Recovery
startup
Recovery Application
completed recovery
Backup
completed
RPO
= Economic loss
An error or
disaster
occurs.
00:00
+
06:00
12:00
Backup
started
RTO
BW
Point in time to
which data is
recovered
Three Elements of a Backup System

Disaster Recovery
Disaster recovery is a higher-level data protection.
 Differences from backup
 Backup focuses on data availability.
 Disaster recovery focuses on data security.
 Backup is used to prevent logical faults from damaging the production system.
 Disaster recovery is used to prevent physical faults from damaging the production
system.
 Generally, the RPO and RTO values of a disaster recovery system are smaller than
those of a backup system.
 Relations with backup
 Both disaster recovery and backup belong to data protection.
 A backup system can also be used to construct some cost-effective disaster
recovery solutions.
 They complement each other.

Disaster Recovery and Its Tiers
RTO
Disaster recovery refers to establishing a systematic data emergency response mode in advance by using scientific
technical means and methods to cope with disasters. The content includes data backup and system backup, business
continuity planning, personnel architecture, communication assurance, crisis management, disaster recovery planning,
disaster recovery schemes, business recovery schemes, emergency response, third-party cooperation organizations, and
supply chain crisis management. The disaster recovery levels range from the module level to system-level and solution-level.
SHARE's seven tiers of disaster recovery released in 1992, were updated in 2012 by IBM as an eight tier model.
(Generally, data backup is usually applied to tier 1 to tier 4, and data disaster recovery is usually applied to tier 4 to tier 7.)
TCO
Tier 7: highly automated, business-integrated solution
Tier 6: zero or little data loss
Tier 5: transaction integrity
Tier 4: point-in-time copies
Tier 3: electronic vaulting
Tier 2: data backup with hot site
Tier 1: data backup with no hot site
Total Cost of Ownership (TCO)
15
minutes
1 to 4
hours
4 to 8
hours
8 to 12
hours
12 to 16 24 hours
hours
Days Weeks

Production array
Synchronous remote replication
Asynchronous remote replication
Disaster recovery array
Remote replication enables data copies to be maintained at two or
more sites in a distance from the source data site to prevent data loss
upon a disaster.
There are various remote replication technologies, among which
synchronous remote replication and asynchronous remote replication
are most widely used in the storage industry.
Remote Replication (HyperReplication)

In the active-active data centers solution, both data centers are running and can carry production
services. The overall service capabilities and system resource usage of the data centers are high.
Data centers can work in either
active-passive mode or active-
active mode.
In active-passive mode, some
services run in data center A,
with data center B as the hot
backup, while other servicesrun
in data center B, with data
centerA as the hot backup. This
achieves approximate active-
active effects.
In active-active mode, all I/O
paths can access active-active
LUNs to achieve load balancing
and seamless failover.
Active-Active Storage (HyperMetro)

a b c
d e f
g h i
j k l
a b c
d e f
g h i
j k l
Snapsh
ot
a b c
d m f
g h n
08:00 am
09:00 am
a b c
d e f
g h i
j k l
Source data
j k l
Data snapshot
Snapshot (HyperSnap)

1. Function: Data is stored concurrently on two independent storage areas (commonly
logical volumes) through the same I/O operations.
2. Benefit
• The two mirror volumes are identified by the host or storage controlled as the
same production volume. Services can be switched over between the two
volumes to improve system reliability.
• Concurrent operations on mirror volumes can improve system performance.
Mirroring (HyperMirror)
LUN 2
LUN 1
I/O

A clone is a copy or multiple copies of source data at a specific point in time.
A snapshot is similar to a stereotyped shadow at a certain point in time, while a cloneis
a stereotyped entity at a certain point in time.
Implementation process
11
Enable the clone function.
Start datasynchronization.
2 2
After datasynchronization
is complete, data on the
primary LUN is the same
as that on the secondary
LUN.
33
After splitting is completed,
the primary and secondary
LUNs become
independent LUNs.
44
The secondary LUN can
be mapped to the host.It
can be used for data
analysis and query.
1
2
3
4
Primary LUN Secondary LUN Primary LUN Secondary LUN
Clone (HyperClone)

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All Rights Reserved.
The information in this document may contain predictive
statements including, without limitation, statements regarding
the future financial and operating results, future product
portfolio, new technology, etc. There are a number of factors
that could cause actual results and developments to differ
materially from those expressed or implied in the predictive
statements. Therefore, such information is provided for
reference purpose only and constitutes neither an offer nor
an acceptance. Huawei may change the information at any
time without notice.
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