Dell EqualLogic PS4000 User manual

Dell EqualLogic
Configuration Guide
Dell EqualLogic
Storage Infrastructure and Solutions

Dell EqualLogic Configuration Guide v11.3
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Revision History
Revision
Date
Changes
v11.1
April 2010
Updated content. Applied new template.
v11.2
July 2010
Quarterly version cycle update: content additions and edits.
V11.3
Oct 2010
Quarterly version cycle update: content additions and edits.
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Table of Contents
1Introduction ........................................................................................................ 1
1.1 Audience....................................................................................................... 1
1.2 Document Structure ......................................................................................... 1
2PS Series Storage Arrays .......................................................................................... 2
2.1 Array Models .................................................................................................. 2
2.2 Feature Comparison ......................................................................................... 3
2.3 Controllers .................................................................................................... 4
2.3.1 Controller Types ........................................................................................ 4
2.3.2 Controller Redundancy................................................................................. 5
2.3.3 Controller Failover ..................................................................................... 5
2.3.4 Firmware ................................................................................................. 7
2.4 RAID Policies .................................................................................................. 9
2.4.1 RAID 5..................................................................................................... 9
2.4.2 RAID 6.................................................................................................... 10
2.4.3 RAID 10 .................................................................................................. 11
2.4.4 RAID 50 .................................................................................................. 12
3Peer Storage Operations......................................................................................... 14
3.1 Groups ........................................................................................................ 14
3.2 Pools........................................................................................................... 14
3.3 Volumes....................................................................................................... 15
3.3.1 Volume Attributes ..................................................................................... 16
3.3.2 Volume Features ....................................................................................... 17
3.3.3 Thin Provisioning....................................................................................... 17
3.3.4 Snapshots ............................................................................................... 18
3.3.5 Cloning .................................................................................................. 18
3.3.6 Replication.............................................................................................. 19
3.3.7 Clustering ............................................................................................... 24
4SAN Design ......................................................................................................... 25
4.1 Implementation of Standards ............................................................................. 25
4.2 General Requirements and Recommendations ......................................................... 25
4.2.1 Quality of Service (QoS) .............................................................................. 26

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4.3 Ethernet Switches and Infrastructure.................................................................... 27
4.3.1 Connecting SAN Switches in a Layer 2 Network................................................... 28
4.3.2 Sizing Inter-Switch Connections ..................................................................... 30
4.3.3 Comparing Inter-Switch Connection Types ........................................................ 31
4.4 Host Configuration Guidelines ............................................................................ 32
4.4.1 Recommendations for Host Connectivity in Redundant SANs................................... 32
4.4.2 Multi-Path I/O .......................................................................................... 33
4.5 EqualLogic iSCSI SAN Design ............................................................................... 35
4.5.1 Redundant SAN Configuration ....................................................................... 35
4.5.2 Partially Redundant SAN Configurations ........................................................... 36
4.6 Integrating 1GbE and 10GbE SANs ........................................................................ 38
5M1000e Blade Chassis Integration.............................................................................. 40
5.1 Guidelines for Stacking Switches in a Blade Chassis................................................... 40
5.2 Single M1000e Enclosure Integration..................................................................... 41
5.3 Multiple M1000e Enclosure Integration .................................................................. 41
5.4 M1000e Ethernet Pass-Through I/O Module ............................................................. 43
5.5 External Tier Stacking ...................................................................................... 43
5.6 Stack to Stack Interconnect ............................................................................... 43
5.6.1 10GbE Uplink Recommendations .................................................................... 43
5.6.2 1GbE Uplink Recommendations ..................................................................... 44
Appendix A Network Ports and Protocols ...................................................................... 47
A.1 Required Ports and Protocols ................................................................................ 47
A.2 Optional Ports and Protocols................................................................................. 47
Appendix B Recommended Switches ........................................................................... 49
B.1 Recommended 1GbE Switches ............................................................................... 49
B.2 Recommended 10GbE Switches.............................................................................. 50
Appendix C Supported iSCSI Initiators.......................................................................... 51
C.1 Hardware iSCSI Initiators (HBAs) ............................................................................ 51
C.2 Software iSCSI Initiators ...................................................................................... 52
C.3 Network Interface Controllers ............................................................................... 53
Appendix D PowerConnect 54xx Switch Configuration ...................................................... 54
D.1 Disabling iSCSI Optimization Setting ........................................................................ 54
D.2 Enabling the PortFast Option to Configure STP Edge Ports ............................................. 55
D.3 Configuring Flow Control ..................................................................................... 55

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D.4 Disabling Unicast Storm Control ............................................................................. 56
D.5 Configuring Jumbo Frames ................................................................................... 57
Appendix E PowerConnect 62xx Switch Configuration ...................................................... 58
E.1 Interface Naming Convention ................................................................................ 58
E.2 Enabling the PortFast Option to Configure STP Edge Ports ............................................. 59
E.3 Configuring Flow Control ..................................................................................... 59
E.4 Disabling Unicast Storm Control ............................................................................. 59
E.5 Configuring Jumbo Frames ................................................................................... 60
Appendix F Cisco IOS based Switch Configuration ........................................................... 61
F.1 Enabling the PortFast Option to Configure STP Edge Ports ............................................. 62
F.2 Configuring Flow Control ..................................................................................... 62
F.3 Disabling Unicast Storm Control ............................................................................. 63
F.4 Configuring Jumbo Frames ................................................................................... 63
Related Publications................................................................................................... 66

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1Introduction
With the Dell™ EqualLogic™ PS Series of storage arrays Dell provides a storage solution that delivers the
benefits of consolidated networked storage in a self-managing, iSCSI storage area network (SAN) that is
affordable and easy to use, regardless of scale. By eliminating complex tasks and enabling fast and
flexible storage provisioning, these solutions dramatically reduce the costs of storage acquisition and
ongoing operations.
To be able to leverage the advanced features provided by an EqualLogic array, a robust, standards-
compliant iSCSI storage area network (SAN) infrastructure must be created. While almost any industry
standard, enterprise class Ethernet switch can be used to connect hosts to the EqualLogic-based virtual
storage volumes, some switches, network interface controllers(NICs), iSCSI Host Bus Adapters (HBAs),
and iSCSI initiators can directly impact the overall performance of the SAN storage solution. The Dell
EqualLogic Configuration Guide is provided as an aid to help storage administrators determine how
best to build an iSCSI infrastructure for use within an EqualLogic SAN solution. This document focuses
on network configuration, host integration and other topics that help to ensure a smooth deployment
with maximum SAN performance.
This document should be used strictly as a guide in planning an EqualLogic SAN solution. It should not
be considered a statement of support for any specific configuration. Actual viability of any
configuration will depend on the capabilities of the individual components (switches, network
interface controllers, initiators, etc.) that make up the SAN infrastructure.
1.1 Audience
This configuration guide is intended for storage administrators, SAN designers, storage consultants, or
anyone who is considering purchasing or has purchased an EqualLogic PS Series Array(s) for use in a
production storage area network. It is assumed that all readers have experience in designing and/or
administering a shared storage solution. Also, there are some assumptions made in terms of familiarity
with all current and possibly future Ethernet standards as defined by the Institute of Electrical and
Electronic Engineers (IEEE) as well as all TCP/IP and iSCSI standards as defined by the Internet
Engineering Task Force (IETF).
1.2 Document Structure
This rest of this configuration guide contains the following sections:
Section 2, PS Series Storage Arrays on page 2
Section 3, Peer Storage Operations on page 14
Section 4, SAN Design on page 25
Section 5, M1000e Blade Chassis Integration on page 40
Appendices:
oNetwork Ports and Protocols on page 47
oRecommended Switches on page 49
oSupported iSCSI Initiators on page 51
oPowerConnect 54xx Switch Configuration on page 54
oPowerConnect 62xx Switch Configuration on page 58
oCisco IOS based Switch Configuration on page 61

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2PS Series Storage Arrays
PS Series Storage SANs provide a peer storage architecture comprised of one or more independent
arrays. Each array contains its own controllers, cache, storage, and interface ports. Grouped together
they can create one or more single instance storage pools that are based on the IETF iSCSI standard.
The capabilities of the PS Series solution are provided through a unique set of software and hardware
capabilities that, when used cooperatively, can provide a full featured SAN solution. The following
sections provide additional insight into specifications and functions of PS Series arrays.
2.1 Array Models
Starting with the PS5000 family of arrays, Dell EqualLogic model names designate various pieces of
information regarding the PS Series array. The "PS" is the product name and stands for "Peer Storage".
The four digit model number indicates the major feature sets and generational information. The first
digit is the "family" and is typically referred to as the "x-thousand" family where "x" is (currently) either
5 or 6. The second digit designates the chassis form-factor (16 drives vs. 48 drives). The last two are
digits designate the controller type (―00‖ indicates a controller with 1GbE ports, ―10‖ indicates a
controller with 10GbE ports).
The letter designation at the end of the model name indicates the array drive technology being used
within the array: "E" indicates SATA technology, "X" indicates 10,000 RPM SAS technology, "XV" indicates
15,000 RPM SAS technology and "S" indicates SSD technology.
Array Model
Drive Type
Number of Drives
PS50E –PS2400E
SATA
14, 56(a)
PS3000X, PS3x00XV
SAS
16
PS4000E
SATA
16
PS4000X, PS4000XV
SAS
16
PS5000E
SATA
16
PS5000X, PS5000XV
SAS
16
PS5500E
SATA
48
PS6000E
SATA
16
PS6000X, PS6000XV
SAS
16
PS6000S, PS6010S
SSD
16
PS6010E
SATA
16
PS6010X, PS6010XV
SAS
16
PS6000XVS, PS6010XVS
SAS / SSD
8 / 8
PS6500E
SATA
48
PS6510E
SATA
48

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PS6510X
SAS
48
(a) PS2400E comprised of 4 drive enclosures, 14 drives each
Table 1: Array Models
2.2 Feature Comparison
The Dell EqualLogic PS6000 Series provides the full range of features and capabilities available with the
EqualLogic PS Series storage products. The Dell EqualLogic PS4000 Series provides a subset of features
and capabilities, targeted at remote office and small to medium business storage deployments. Table 2
provides a feature and scalability comparison between the various array models offered.
Feature
PS50 –PS6XX01
Group with
PS4000 Only
Maximum members in a group
162
2
Maximum members in a pool
8
2
Maximum volumes in a group
1024
256
Maximum number of pools in a group
4
2
Snapshots in a group
10,000
2048
Snapshots of a volume
512
128
Replicas of a volume
512
128
Replication partners per group
16
2
Replication partners per volume
1
1
Volumes in a collection
8
8
Collections in a group (snapshot and
replication)
100
100
Volume connections per pool and per group
(each time an iSCSI initiator connects to a
volume counts as a connection)
2048(a)with 4 pools,
maximum 512 per pool
4096(b) with 4 pools,
maximum 1024 per pool
256 with 2 pools,
maximum 128 per pool
Access control records per volume and its
snapshots
16
16
Maximum volumes enabled for replication
128
32
Simultaneous management sessions (any
combination of GUI, telnet, or scripting
sessions)
7
7
(a) Up to controller firmware level 4.x.x
(b) Beginning with controller firmware level 5.x.x
Table 2: Array Feature Comparison
1
In a mixed group of PS6000, PS6500 and PS4000 the higher limits normally prevail
2
In a mixed group of PS6000, PS6500 and PS4000 arrays the maximum number of PS4000 arrays in the group is two

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2.3 Controllers
Since the EqualLogic PS Series was introduced, there have been several different array models released
with new features, better performance and greater storage capacity. The storage array controllers
were improved to take advantage of advances in the underlying networking and storage technologies.
2.3.1 Controller Types
Array controllers can be identified and differentiated by the controller "type" designation. Each
controller type will have a different colored label to help quickly identify the controller type. Table 3
lists each Dell EqualLogic controller along with some characteristics about each.
Controller
Type
Faceplate
Network
Interfaces
Storage
Type
Notes
Type 1
3 x 1GbaseT
3 x 1Gb SFP (combo)
SATA
Original Controller
Design
PS50 –PS2400
1GB Cache
Type 2
3 x 1GbaseT
3 x 1Gb SFP (combo)
SATA
PS50 –PS2400
1GB Cache
Type 3 SAS
Type 3 SATA
3 x 1GbaseT
SAS
SATA
PS3000 –PS5000
1GB Cache
Small Form Factor
Cannot mix Type 3 SAS
with Type 3 SATA
Type 4
3 x 1GbaseT
SAS
PS3000 –PS5000
1GB Cache
Small Form Factor
Cannot mix Type 3 SAS
with Type 4 controller
Type 5
3 x 1GbaseT
SATA
PS3000 –PS5000
1GB Cache
Small Form Factor
Cannot mix Type 3 SAS
with Type 5 controller
Type 6
3 x 1GbaseT
SATA
PS5500 only
2GB Cache
Small Form Factor
Type 7
4 x 1GbaseT
SAS
SATA
SSD
PS6000 –PS6500
2GB Cache
Small Form Factor
Cannot mix SAS and
SATA drives in same
array
Type 8
2 x1GbaseT
1 x 10/100Mb mgt
SAS
SATA
PS4000 only
2GB Cache
Small Form Factor
Cannot mix SAS and
SATA drives in same
array

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Type 9
2 x 1GbaseT
1 x 10/100Mb mgt
SAS
SATA
2nd generation PS4000
2GB Cache
Small Form Factor
Cannot mix SAS and
SATA drives in same
array
Type 10
2 x 10GB SFP+
1 x 10/100Mb mgt
SAS
SATA
SSD
10Gb Ethernet
PS6010 –PS6510
2GB Cache
Small Form Factor
Table 3: Array Controller Type Comparison
2.3.2 Controller Redundancy
Each array can be configured with either a single controller, or dual redundant controllers. The single
controller configuration will provide the same level of I/O performance as a dual controller
configuration. The dual controller configuration provides for redundancy. Redundant controllers will
prevent volume connections between hosts and SAN from being dropped in the event of an active
controller failure.
The Active Controller is the controller which is processing all disk and network I/O operations for the
array.
A second controller in dual controller configurations will always be in a ―passive‖ operating mode. In
this mode, the secondary controller will exhibit the following characteristics:
Each of its Ethernet ports are electrically inactive (active lights are off)
The passive controller cache mirrors the cache of the active controller.
2.3.3 Controller Failover
To support redundant controller fail over, each Ethernet port on the active controller that is connected
to the SAN must have its corresponding port on the passive controller also connected to the same SAN
network. In the event of a controller failure, the passive controller will immediately activate and
continue to process all data requests to the array. The following changes occur during fail over:
The backup controller automatically enables each of the corresponding Ethernet ports that
were enabled on the failed primary controller
The IP addresses that were assigned to each of the failed controller Ethernet ports are
reassigned to the corresponding ports on the second controller.
A link failure on one or more of the Ethernet ports on the active controller does not constitute a
controller failure. For this reason, it is important to ensure that ports from each controller are
connected to at least two different switches. This will prevent a switch failure from also disabling all
paths between a host and its connected volumes.
It is critical that port connections for both controllers are configured so that the corresponding ports
on each controller are connected to the SAN. If port 0 on the active controller is the only port
connected to the SAN, then port 0 on the passive controller must also be connected to the SAN. This is
shown in the partial and fully connected controller failover scenarios illustrated in Figure 1 and Figure
2 below. Note how IP addresses are reassigned to the ports during the failover process.

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Figure 1 Partially Connected Controller Failover

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2.3.4 Firmware
Each EqualLogic PS Series array runs a core operating system in firmware that provides all of the PS
Series features and functionality. The firmware version is defined using a version number and will be
updated from time to time as new features are added or for general maintenance improvements.
The firmware version number takes the following form: "X.Y.Z":
"X" is used to identify the "major" release number. This changes when there are very significant
changes in the features and functionality.
"Y" is the "minor" release number. This changes as new minor features or improvements in
existing features are made for a given major release.
"Z" denotes maintenance releases. This changes whenever a maintenance release level is
released to resolve any identified technical or usability issues.
Figure 2 Fully Connected Controller Failover

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Firmware Upgrade
Before beginning a firmware upgrade process, you must review the Release Notes for the firmware
update revision. The release notes will be included with the firmware update kit. All firmware update
kits are available at http://www.equallogic.com/support/ (Support ID required for login access). The
release notes contain the latest information and guidelines for:
Completing the upgrade with minimal potential for service disruption
Operating system and iSCSI initiator configuration settings that will minimize potential for I/O
disruption during the upgrade process
Latest updates to the supported firmware upgrade paths
In addition to the Release Notes, the process for updating controller firmware is described in detail in
the following document (Support ID required for login access):
PS Series Storage Arrays: Updating Storage Array Firmware, available at:
https://www.equallogic.com/support/download_file.aspx?id=594
Supported firmware upgrade paths (up to version 5.0.x) are shown in Table 4 below:
Starting Firmware
Version
Ending Firmware
Version
4.2.*, 4.3.*
5.0.*
4.2.*
4.3.*
4.1.*
4.2.*, 4.3.*
4.0.*
4.1.*
3.2.*, 3.3.*
4.0.*
3.1.*
3.2.*, 3.3.*
3.0.*
3.1.*
Table 4 Controller Firmware Upgrade Paths

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2.4 RAID Policies
Each array in an EqualLogic array group is configured with a single RAID policy. Arrays (or group
members) within the same storage pool that have the same RAID policy will cooperatively work to host
volumes by distributing those volumes over multiple arrays. Two things defined the RAID policy:
RAID level
hot-spare configuration
Each array implements a default RAID policy that includes a hot-spare. To configure a RAID policy that
does not include a hot-spare you must manually initialize the array using the Command Line Interface.
2.4.1 RAID 5
RAID 5 (striped disks with distributed parity) will combine N disks in an arrangement where each stripe
consists of N-1 disks that contain data blocks plus 1 disk that contains a parity block. For each stripe,
the parity block will be placed on a different disk ensuring that the parity blocks are not located on a
single disk in the RAID set. RAID 5 implementations can tolerate a single drive failure without data
loss.
For EqualLogic arrays using a RAID 5 policy, Table 5 shows the drive layouts that are enforced based on
the number of drives in each array and the hot spare configuration.
Disk
Drives
Hot Spare
No Hot Spare
7
6 Data/Parity
1 Hot-spare
RAID Policy for RAID 5
without a hot spare is not
supported
8
7 Data/Parity
1 Hot-spare
14
13 Data/Parity
1 Hot-spare
16
15 Data/Parity
1 Hot-spare
48(a)
46 Data/Parity
2 Hot-spares
(a) 48 drive arrays implement multiple RAID 5 sets within a chassis
Table 5: RAID 5 Drive Layouts
For EqualLogic arrays using a RAID 5 policy, the total quantity of raw storage available can be
computed based on number of drives and the hot spare configuration. The Table 6 below shows the
amount of raw storage available using the hot spare drive layouts specified in Table 5 above.
Note: Configuring a RAID policy that does not include a hot-spare will increase the risk
potential for data loss in the event of multiple drive failure.

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Disk Drive
Qty / Size
50(a)
100(a)
74
146
250
300
400
450
500
600
750
1000
2000
7(b)
-
-
-
-
1250
-
-
-
-
-
-
-
-
8(c)
-
-
-
-
1500
-
-
-
-
-
-
-
-
14(d)
-
-
888
-
3000
-
4800
-
6000
-
-
-
-
16
700
1400
-
2044
3500
4200
5600
6300
7000
8400
10500
14000
-
48
-
-
-
-
-
-
-
-
21000
25200
-
42000
84000
(a) Solid State Disk
(b) Legacy PS50E
(c) PS4000E and PS6000E only
(d) Legacy PS70E,PS100E, PS100X, PS200E and PS300E
Table 6: RAID 5 Total Storage Available with Hot Spares (in GB)
2.4.2 RAID 6
RAID6 (striped set with dual distributed parity) combines N disks in an arrangement where each stripe
consists of N-2 disks that contains data blocks and 2 disks that contain parity blocks. Each parity block
generates parity using a different ―view‖ of the data blocks depending on the RAID 6 implementation.
RAID 6 implementations can tolerate up to 2 drive failures per RAID set at the same time without data
loss. RAID 6 is not recommended for workloads consisting mainly of random writes. For EqualLogic
arrays using a RAID 6 policy, Table 7 shows the drive layouts that are enforced based on the number of
drives in each array and the hot spare configuration.
Disk Drives
Hot Spare
No Hot Spare
7
6 Data/Parity
1 Hot-spare
7 Data/Parity
8
7 Data/Parity
1 Hot-spare
8 Data/Parity
14
13 Data/Parity
1 Hot-spare
14 Data/Parity
16
15 Data/Parity
1 Hot-spare
16 Data/Parity
8 / 8(c)
13 Data/Parity(d)
1 Hot-spare
16 Data/Parity
48(a)
47 Data/Parity
1 Hot-spare
N/A(b)
(a) 48 drive arrays implement multiple RAID 6 sets within a single chassis.
(b) 48 drive arrays cannot implement a no hot-spare RAID policy.
(c) PS60x0 XVS with 8x 100GB SSD and 8x 450GB SAS.
(d) One 450Gb hot spare, 2x 450 Gb parity and 2x 100Gb SSD parity.
Table 7: RAID 6 Drive Layouts
Table 8 shows the amount of raw storage available using the hot spare drive layouts specified in Table
7 above.

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Disk Drive
Qty / Size
50(a)
100(a)
74
146
250
300
400
450
500
600
750
1000
2000
7(b)
-
-
-
-
1000
-
-
-
-
-
-
-
-
8(c)
-
-
-
-
1250
-
-
-
-
-
-
-
-
14(d)
-
-
740
-
2500
-
4000
-
5000
-
-
-
-
16
650
1300
-
1898
3250
3900
5200
5850
6500
7800
9750
13000
-
8 / 8(e)
-
-
-
-
-
-
-
2850
-
-
-
-
-
48
-
-
-
-
-
-
-
-
19500
23400
-
39000
78000
(a) Solid State Disk
(b) Legacy PS50E
(c) PS4000E and PS6000E only
(d) Legacy PS70E, PS100E, PS100X, PS200E, PS300E and PS400E
(e) PS60x0 XVS with 8 x 100GB SSD and 8 x 450GB SAS
Table 8: RAID 6 Total Storage Available with Hot Spares (in GB)
2.4.3 RAID 10
RAID 10 (mirrored sets in a striped set) combines two high performance RAID types: RAID 0 and RAID 1.
A RAID 10 is created by first building a series of two disk RAID 1 mirrored sets, and then distributing
data over those mirrors. RAID 10 implementations can tolerate one drive failure per mirror pair.
For EqualLogic arrays using a RAID 10 policy, Table 9 shows the drive layouts that are enforced based
on the number of drives in each array and the hot spare configuration.
Disk
Drives
Hot Spare
No Hot Spare
7
6 Data (3 mirrors)
1 Hot-spare
N/A(a)
8
6 Data (3 mirrors)
2 Hot-spares
8 data (4 mirrors)
14
12 Data (6 mirrors)
2 Hot-spares
14 Data (7 mirrors)
16
14 Data (7 mirrors)
2 Hot-spares
16 Data (8 mirrors)
48
46 Data (23 mirrors)
2 Hot-spares
N/A(b)
(a) Not supported. An even number of drives is required by RAID 10
(b) 48 drive arrays cannot implement a no hot-spare policy.
Table 9: RAID 10 Drive Layouts
For EqualLogic arrays using a RAID 10 policy, the total quantity of raw storage available can be
computed based on number of drives and the hot spare configuration. The Table 10 below shows the
amount of raw storage available using the hot spare drive layouts specified in Table 9 above.

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Disk Drive
Qty / Size
50(a)
100(a)
74
146
250
300
400
450
500
600
750
1000
2000
7(b)
-
-
-
-
750
-
-
-
-
-
-
-
-
8(c)
-
-
-
-
750
-
-
-
-
-
-
-
-
14(d)
-
-
444
-
1500
-
2400
-
3000
-
-
-
-
16
350
700
-
1022
1750
2100
2800
3150
3500
4200
5250
7000
-
48
-
-
-
-
-
-
-
-
11500
13800
-
23000
46000
(a) Solid State Disk
(b) Legacy PS50E
(c) PS4000E and PS6000E only
(d) Legacy PS70E,PS100E, PS100X, PS200E, PS300E and PS400E
Table 10: RAID 10 Total Storage Available with Hot Spares (in GB)
2.4.4 RAID 50
RAID 50 (RAID 5 sets in a striped set) is created by first creating two or more RAID 5 sets, and then
striping data over those RAID5 sets. RAID 50 implementations can tolerate a single drive failure per
RAID5 set.
For EqualLogic arrays using a RAID 50 policy, Table 11 shows the drive layouts that are enforced based
on the number of drives in each array and the hot spare configuration.
Disk
Drives
Hot Spare
No Hot Spare
7
6 Data/Parity
1 Hot-spare
N/A(a)
8
6 Data/Parity
2 Hot-spares
8 Data/Parity
14
12 Data/Parity
2 Hot-spares
14 Data/Parity
16
14 Data/Parity
2 Hot-spares
16 Data/Parity
48(b)
46 Data/Parity
2 Hot-spares
N/A(c)
(a) RAID 50 requires an even number of disk drives. A 7 drive configuration without hot-spare
would result in odd number of disk drives.
(b) 48 drive arrays implement stripes across multiple RAID 5 sets within a single chassis.
(c) 48 drive arrays cannot implement a no hot-spare policy.
Table 11: RAID 50 Drive Layouts
For EqualLogic arrays using a RAID 50 policy, the total quantity of raw storage available can be
computed based on number of drives and the hot spare configuration. The Table 12 below shows the
amount of raw storage available using the hot spare drive layouts specified in Table 11 above.

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Disk Drive
Qty / Size
50(a)
100(a)
74
146
250
300
400
450
500
600
750
1000
2000
7(b)
-
-
-
-
1000
-
-
-
-
-
-
-
-
8(c)
-
-
-
-
1000
-
-
-
-
-
-
-
-
14(d)
-
-
740
-
2500
-
4000
-
5000
-
-
-
-
16
600
1200
-
1752
3000
3600
4800
5400
6000
7200
9000
12000
-
48
-
-
-
-
-
-
-
-
19500
23400
-
39000
78000
(a) Solid State Disk
(b) Legacy PS50E
(c) PS4000E and PS6000E only
(d) Legacy PS70E,PS100E, PS100X, PS200E, PS300E and PS400E
Table 12: RAID 50 Total Storage Available with Hot Spares (in GB)

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3Peer Storage Operations
3.1 Groups
A PS Series SAN Group is a Storage Area Network (SAN) comprised of one or more PS Series arrays
connected to an IP network. Each array in a group is called a group member. Each member is assigned
to a storage pool. There can be up to 4 pools within the group.
A group can consist of up to 16 arrays of any family or model as long as all arrays in the group are
running firmware with the same major and minor release number. For example, it is supported to have
different arrays in the same group running different maintenance release levels, as long as their major
and minor revision levels match. An example of this would be running version 4.0.1 and 4.0.3 on
different arrays in the same group. An example of an unsupported configuration would be different
arrays in the same group running 4.0.1 and 4.1.0 (the minor versions differ). The only exception to this
rule is for short term time periods when array firmware versions may be out of sync while upgrading
the firmware on each array within a group. Features available for use within the group are determined
by the lowest version of FW running within the group.
3.2 Pools
A pool is a container that each member is assigned after being added to the group. A pool can have
between 1 to 8 members. There is always at least one pool in any group and it is called the ―default
pool‖ unless the name is changed. Regardless of the name of this pool, it is always considered the
default storage pool. All newly added members are automatically assigned to the default pool. The
default pool cannot be deleted.
Pools can be used as part of an overall tiered storage strategy for the SAN. Tiered storage is storage
that is differentiated and optimized for the type of applications and data being hosted. Instead of
optimizing all of the storage in the group for maximum storage utilization, a tiered storage system
allows for the administrator to optimize different arrays for a variety of requirements such as
application performance requirements or cost efficiency.
Pools are the containers that provide scope for all automated storage optimization features of the
group. Pools with multiple arrays can implement different RAID policies within the pool. The
EqualLogic automated optimization features will automatically move a volume from an array or set of
arrays with one RAID policy to another array or set of arrays with a different RAID policy if it is
determined that the application needs more (or less) performance.
The following rules apply to pools:
Each member can be assigned to only one pool.
Each pool can host up to 8 members.
Each group will have at least 1 pool –the default pool.
Note: It is recommended that all arrays run the exact same version of FW at all times,
except during a FW upgrade process. (See Section 2.3.4 on page 7 for more information.)

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Each group can have up to 4 pools.
PS5500E, PS6500E/X and PS6510E/X must reside in a different pool from other arrays.
PS5500E, PS6500E/X and PS6510E/X can coexist in the same pool.
Figure 3 shows a PS Series group with the maximum of 4 pools. Note the use of Pool 3 for containing
PS5500/PS6500 series arrays only. Also note that Pool 3 contains arrays that implement both 1GbE and
10GbE controllers.
The following best practices should be considered for storage pools:
Do not mix arrays with different drive speeds within a single pool unless they are running a
unique RAID policy
Do not mix arrays with different drive technologies (SATA, SAS, SSD) within a single pool unless
they are running a unique RAID policy.
Do not mix arrays with different controller speeds (1GbE, 10GbE) within a single pool unless
they are each running unique RAID policies.
To override the automated performance decisions for a specific volume, indicate a ―preferred‖
RAID type for that volume. If that RAID type exists within the pool, the volume will reside on
those arrays that match the preferred RAID policy for the volume.
3.3 Volumes
Volumes provide the storage allocation structure within an EqualLogic SAN. Volumes are seen on the
network as iSCSI targets by hosts and are presented to the user as disk drives once the iSCSI initiator
Figure 3 Tiered Pools in a PS Series Group