System Availability and
Data Protection of Infortrend’s ESVA
Storage Solution
White paper
Abstract
This white paper analyzes system availability and data protection on
Infortrend’s ESVA storage systems. ESVA systems feature 99.999%
availability and include excellent data protection, including RAID protection
and local and remote replication capabilities, to ensure that users can enjoy
extremely reliable and stable storage operations.
System Availability and Data Protection of Infortrend’s ESVA Storage Solution
Table of Contents
ESVA (Enterprise Scalable Virtualized Architecture) Storage Systems .............. 3
Combination of Features Contribute to ESVA’s Excellent Reliability .................. 4
ESVA’s Advanced Hardware Design Delivers High System Availability.............. 5
Component Redundancy ............................................................................................. 5
“Five Nines” System Availability................................................................................... 5
ESVA Data Protection Features................................................................................ 7
RAID Protection ........................................................................................................... 7
Local and Remote Replication Capabilities ................................................................. 8
Appendix I: Detailed Analysis of ESVA’s “Five Nines” System
Availability ................................................................................................................ 10
Appendix II: Local and Remote Replication Specifications on ESVA................ 12
2
Copyright © 2010 Infortrend Technology, Inc. All rights reserved. Infortrend, ESVA, EonStor and EonPath are trademarks or registered trademarks
of Infortrend. All other marks and names mentioned herein may be trademarks of their respective owners. The information contained herein is
subject to change without notice. The content provided as is, without express or implied warranties of any kind.
ESVA_WP010_111910_V1.0
System Availability and Data Protection of Infortrend’s ESVA Storage Solution
ESVA (Enterprise Scalable Virtualized Architecture)
Storage Systems
The Infortrend ESVA (Enterprise Scalable Virtualized Architecture) Series is a
leading storage solution designed for mid-range enterprise SAN. At affordable
prices, it meets mission-critical storage demands for performance, scalability
and reliability with advanced hardware designs and comprehensive data
services. On the innovative Enterprise Scalable Virtualized Architecture, various
features, including storage virtualization, thin provisioning, distributed load
balancing, automated storage tiering, automatic data migration, prioritized
volume accessibility, snapshot and replication, are consolidated to realize
optimal business benefits. With ESVA systems, users can optimize ROI, simplify
storage infrastructure, and maximize application productivity.
For more information about Infortrend’s ESVA storage systems, please visit our
website: http://esva.infortrend.com/
3
Copyright © 2010 Infortrend Technology, Inc. All rights reserved. Infortrend, ESVA, EonStor and EonPath are trademarks or registered trademarks
of Infortrend. All other marks and names mentioned herein may be trademarks of their respective owners. The information contained herein is
subject to change without notice. The content provided as is, without express or implied warranties of any kind.
ESVA_WP010_111910_V1.0
System Availability and Data Protection of Infortrend’s ESVA Storage Solution
Combination of Features
Excellent Reliability
Contribute
to
ESVA’s
Infortrend’s ESVA systems are designed to be extremely reliable and secure.
This is achieved with advanced hardware design that ensures high system
availability and data protection features that help to guard data stored in ESVA
systems. The following figure highlights the four major elements that contribute
to ESVA’s reliability:
Figure 1: Key Elements Contributing to ESVA System Reliability
4
Copyright © 2010 Infortrend Technology, Inc. All rights reserved. Infortrend, ESVA, EonStor and EonPath are trademarks or registered trademarks
of Infortrend. All other marks and names mentioned herein may be trademarks of their respective owners. The information contained herein is
subject to change without notice. The content provided as is, without express or implied warranties of any kind.
ESVA_WP010_111910_V1.0
System Availability and Data Protection of Infortrend’s ESVA Storage Solution
ESVA’s Advanced Hardware Design Delivers High
System Availability
Component Redundancy
The first step in achieving a reliable and stable storage system is designing the
system’s hardware in such a way that the system is nearly always available to
users. Design features that are important in this respect are high-quality,
redundant hardware components and the availability of the overall ESVA
system.
Redundant hardware components on ESVA systems include the RAID
controllers, power supplies and cooling modules. The main benefit of redundant
components is that a system will not shut down as a result of a single
component failure. If a single component fails, the system can still operate
normally. With redundant controllers, fault-tolerant data paths can be created so
that data transmission to and from host applications can continue even in the
event of a failure of one of the controllers.
“Five Nines” System Availability
System availability is an indication of normal operating time vs. non-operating
time (due to system failure or other factors).
Several statistics are important to determine system availability, including:
•
MTBF (Mean Time Between Failure): the average time between two
failures of a component or system.
•
MTTR (Mean Time To Recovery): the average time needed to repair a
component or system after a failure so that it operates normally again.
•
MTTF (Mean Time To Failure): average time between the resumption of
normal operations to the next failure.
Availability is calculated as follows: MTTF/MTBF.
5
Copyright © 2010 Infortrend Technology, Inc. All rights reserved. Infortrend, ESVA, EonStor and EonPath are trademarks or registered trademarks
of Infortrend. All other marks and names mentioned herein may be trademarks of their respective owners. The information contained herein is
subject to change without notice. The content provided as is, without express or implied warranties of any kind.
ESVA_WP010_111910_V1.0
System Availability and Data Protection of Infortrend’s ESVA Storage Solution
The table below shows often-used availability statistics (expressed in
percentages) and the corresponding downtime of a system (per year). Obviously,
each minute of
downtime can have far-reaching consequences for enterprises. The differences
between the percentages shown below can thus be very meaningful for
companies that are evaluating storage systems for purchase.
Availability
Downtime Per Year
98%
7.30 days
99%
3.65 days
99.5%
1.83 days
99.9%
8.76 hours
99.99%
52.56 minutes
99.999%
5.26 minutes
99.9999%
31.54 seconds
Table 1: Widely Used Availability Indicators and Corresponding Downtime
Infortrend’s ESVA systems feature an availability of 99.999% (“five nines”),
meaning that on average an ESVA system will only suffer approximately five
minutes of downtime per year 1 . In terms of hardware, ESVA systems are
extremely reliable and allow users to enjoy stable system operations.
1
For detailed calculations at the basis of ESVA systems’ availability, see the Appendix.
6
Copyright © 2010 Infortrend Technology, Inc. All rights reserved. Infortrend, ESVA, EonStor and EonPath are trademarks or registered trademarks
of Infortrend. All other marks and names mentioned herein may be trademarks of their respective owners. The information contained herein is
subject to change without notice. The content provided as is, without express or implied warranties of any kind.
ESVA_WP010_111910_V1.0
System Availability and Data Protection of Infortrend’s ESVA Storage Solution
ESVA Data Protection Features
Infortrend’s ESVA storage systems include a number of features that ensure
excellent data protection. These features include RAID protection and data
services, such as local and remote replication capabilities.
RAID Protection
RAID (Redundant Array of Independent Disks) technology is at the core of ESVA
systems. RAID involves the use of two or more disk drives to improve
performance, error recovery, and fault tolerance. Mainstream RAID levels are
described below:
•
RAID 0 (Disk striping): delivers maximum performance, without any data
redundancy.
•
RAID 1 (Disk mirroring): data is mirrored, or copied, on two different disks,
offering maximized data redundancy and excellent reliability.
•
RAID 3 (Disk striping with dedicated parity): delivers excellent performance,
while one dedicated parity drive offers data redundancy.
•
RAID 5 (Disk striping with interspersed parity): delivers excellent
performance; data redundancy is same as RAID 3, with the difference that
parity data is interspersed among all member drives.
•
RAID 6 (Disk striping with two interspersed parity disks): a RAID 6
configuration is essentially an extension of a RAID 5 configuration with a
second independent distributed parity scheme that offers even better data
redundancy.
Infortrend ESVA systems are by default configured to operate with RAID 5, with
excellent data redundancy to ensure that data will not be lost due to failure of
individual disk drives.
If users feel that the data protection offered by RAID 5 is not enough, they can
choose to configure their storage system with RAID 6. This RAID level offers an
extra parity scheme to ensure that data is even better protected.
7
Copyright © 2010 Infortrend Technology, Inc. All rights reserved. Infortrend, ESVA, EonStor and EonPath are trademarks or registered trademarks
of Infortrend. All other marks and names mentioned herein may be trademarks of their respective owners. The information contained herein is
subject to change without notice. The content provided as is, without express or implied warranties of any kind.
ESVA_WP010_111910_V1.0
System Availability and Data Protection of Infortrend’s ESVA Storage Solution
Local and Remote Replication Capabilities
In addition, ESVA systems offer data services including local and remote
replication capabilities that offer a number of ways in which to improve data
protection and avoid data loss. Local replication capabilities include snapshot
and volume copy/mirror, while remote replication can be done in either
synchronous or asynchronous mode.
Snapshots
allow
users
to
perform
instant,
low-impact
backups
with
space-efficient differential copies. In the instant of snapshot creation, a
point-in-time data image is taken without disrupting online applications. Based
on the image, data changes will be copied to the snapshot volume when new
writes occur. With copy-on-write design, snapshots protect data from accidental
modifications, deletions and corruptions with minimal capacity requirements and
performance overhead. By accessing a snapshot copy as the desired recovery
point, users can immediately restore system availability from data disruption.
Figure 2: ESVA Snapshot Feature
Volume mirror/copy allows users to non-disruptively create full data copies in a
single storage pool. The copies created with volume mirror can be constantly
synced with the source data or split as independent copies. When a volume
fatally fails, these copies can be constantly synced and can be leveraged for
quick recovery without any data loss. Split copies can be used to enhance
operational resilience by allowing shared access of critical information among
production and batch applications, such as testing, data mining, scientific
analysis and tape backup. As business needs require, the split copies can be
quickly re-synced with source.
8
Copyright © 2010 Infortrend Technology, Inc. All rights reserved. Infortrend, ESVA, EonStor and EonPath are trademarks or registered trademarks
of Infortrend. All other marks and names mentioned herein may be trademarks of their respective owners. The information contained herein is
subject to change without notice. The content provided as is, without express or implied warranties of any kind.
ESVA_WP010_111910_V1.0
System Availability and Data Protection of Infortrend’s ESVA Storage Solution
Users can also create copies independent from source with volume copy
technology. These copies are ideal for time-critical applications since they are
immediately available for use even before the copying process is fully completed.
Similar to split
copies created by volume mirror, the editing of independent copies does not
affect the service level of primary applications or their data integrity.
Remote replication capability allows users to create full data copies across
storage pools, either in synchronous or asynchronous mode. If source data fails
due to system malfunctions or disasters, users can leverage the disk-based
remote copy to restart service within only minutes. If the source needs to resume
its role, it can be quickly synced with the remote copy for only differentials.
To further ensure the integrity of the remote data, remote replication allows users
to protect the remote copy with snapshot technology. Granular snapshot images
can help restore the corrupt remote copy in seconds when it needs to resume
business service.
Figure 3: Full data copies in a single storage pool (local replication) and across storage pools
(remote replication)
9
Copyright © 2010 Infortrend Technology, Inc. All rights reserved. Infortrend, ESVA, EonStor and EonPath are trademarks or registered trademarks
of Infortrend. All other marks and names mentioned herein may be trademarks of their respective owners. The information contained herein is
subject to change without notice. The content provided as is, without express or implied warranties of any kind.
ESVA_WP010_111910_V1.0
System Availability and Data Protection of Infortrend’s ESVA Storage Solution
Appendix I: Detailed Analysis of ESVA’s “Five Nines”
System Availability
ESVA system availability is based on individual component availability and the
way in which individual components are linked together.
The availability of individual components is calculated based on component
specifications of component suppliers or Infortrend. From these individual
availability figures, the availability of the overall ESVA system can be calculated.
Analyzed components to determine system availability include:
•
•
Ctrl PCBA:
Host Board:
Printed Circuit Board Assembly located within the controller
Host board located within the controller
•
BP:
front
Backplane board within system enclosure; separates the
and rear sections of the enclosure
•
FAN:
Cooling fan modules; protect the system from overheating
•
PSU:
subsystem
Power supply units; provides constant power to the
The table below shows availability of individual components and overall system
availability. Detailed formulas are provided in the notes that follow the table.
Table 2: ESVA System Availability
Notes:
•
Individual component availability formula: MTTF/MTBF x 100
10
Copyright © 2010 Infortrend Technology, Inc. All rights reserved. Infortrend, ESVA, EonStor and EonPath are trademarks or registered trademarks
of Infortrend. All other marks and names mentioned herein may be trademarks of their respective owners. The information contained herein is
subject to change without notice. The content provided as is, without express or implied warranties of any kind.
ESVA_WP010_111910_V1.0
System Availability and Data Protection of Infortrend’s ESVA Storage Solution
•
Redundant availability (parallel-coupled) formula: (1 - [(1-A#1) x (1-A#2)]) x
100
o A#1=Availability of Component #1 of a redundant pair
o A#2=Availability of Component #2 of a redundant pair
o Availability in decimal numbers
•
Overall ESVA system availability: Ctrl PCBA availability x Host Board
availability x BP availability x FAN availability x PSU availability x 100
o Except for BP (single component availability), other availability
numbers in this formula are for parallel-coupled redundant
components
o Component availability in decimal numbers
11
Copyright © 2010 Infortrend Technology, Inc. All rights reserved. Infortrend, ESVA, EonStor and EonPath are trademarks or registered trademarks
of Infortrend. All other marks and names mentioned herein may be trademarks of their respective owners. The information contained herein is
subject to change without notice. The content provided as is, without express or implied warranties of any kind.
ESVA_WP010_111910_V1.0
System Availability and Data Protection of Infortrend’s ESVA Storage Solution
Appendix
II:
Local
Specifications on ESVA
and
Remote
Replication
The table below shows local and remote replication specifications for different
ESVA models.
Table 3: Local and Remote Replication Specifications on ESVA Systems
12
Copyright © 2010 Infortrend Technology, Inc. All rights reserved. Infortrend, ESVA, EonStor and EonPath are trademarks or registered trademarks
of Infortrend. All other marks and names mentioned herein may be trademarks of their respective owners. The information contained herein is
subject to change without notice. The content provided as is, without express or implied warranties of any kind.
ESVA_WP010_111910_V1.0
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