Sun Microsystems SPARCstorage 100 Series User manual

SPARCstorageArrayConfigurationGuide
Part No.: 802-2041-10
Revision A, March 1995
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1995 Sun Microsystems, Inc.
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iii
Contents
1. Product Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
1.1 SPARCstorage Array Model 100 System Features . . . . . . 1-1
1.2 SPARCstorage Array Model 200 System Features . . . . . . 1-3
1.3 General Information for SPARCstorage Array Model 100 and
200 Systems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
2. Hardware Configurations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
2.1 Option 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
2.2 Option 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
2.3 Option 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
2.4 Option 4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5
3. Software Configurations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
3.1 Independent Disks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
3.2 Striping (RAID 0) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
3.3 Mirroring (RAID 1). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3
3.4 Mirroring Striped Disks (RAID 0 + 1) . . . . . . . . . . . . . . . . 3-4
3.5 RAID 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5

iv SPARCstorage Array Configuration Guide—March 1995
3.6 Determining Which RAID Level to Use . . . . . . . . . . . . . . 3-6
3.7 Other Facts on RAID and the SPARCstorage Array . . . . 3-7

v
Figures
Figure 1-1 SPARCstorage Array Model 100 Series . . . . . . . . . . . . . . . . . . . 1-1
Figure 1-2 Internal Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
Figure 1-3 SPARCstorage Array Model 200 Series Subsystem . . . . . . . . . 1-3
Figure 2-1 Option 1 Connection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
Figure 2-2 Option 2 Connection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
Figure 2-3 Option 3 Connection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
Figure 2-4 Option 4 Connection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5
Figure 3-1 Example of Striped Data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
Figure 3-2 Example of Mirrored Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3
Figure 3-3 Example of Mirroring Striped Data . . . . . . . . . . . . . . . . . . . . . . 3-4
Figure 3-4 Graphical Representation of RAID 5 Writes . . . . . . . . . . . . . . . 3-6

vi SPARCstorage Array Configuration Guide—March 1995

vii
Tables
Table 2-1 Option 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
Table 2-2 Option 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
Table 2-3 Option 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
Table 2-4 Option 4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5
Table 3-1 Comparisons of RAID Levels . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-7

viii SPARCstorage Array Configuration Guide—March 1995

1-1
ProductDescription 1
1.1 SPARCstorage Array Model 100 System Features
The SPARCstorage™ Array Model 100 Series provides SCSI disk expansion for
SPARCstation™, SPARCserver™ and SPARCcenter™ systems. It features three
drive trays—each tray configured with up to ten half-height, single-connector,
3.5-inch disk drives.
The SPARCstorage Array Model 100 Series, shown in Figure 1-1, features front
and rear component accessibility.
Figure 1-1 SPARCstorage Array Model 100 Series

1-2 SPARCstorage Array Configuration Guide—March 1995
1
Internal system components (see Figure 1-2) are:
•Power supply
•Backplane
•Array controller, with
•Fibre Channel Optical Module (FC/OM)
•Battery module
•Fan tray
•Drive trays (3)
Figure 1-2 Internal Components
Array controller
Power supply
Drive tray
Fan tray
Backplane

Product Description 1-3
1
1.2 SPARCstorage Array Model 200 System Features
The SPARCstorage Array Model 200 Series is a rackmount disk array
controller. Up to six Differential SCSI disk trays may be connected to it. See
Figure 1-3.
Figure 1-3 SPARCstorage Array Model 200 Series Subsystem
Fan tray
Power supply
Diagnostic
module
Controller
Differential
SCSI interface

1-4 SPARCstorage Array Configuration Guide—March 1995
1
Functional parts of the SPARCstorage Array Model 200 Series hardware
include:
•Removable power supply
•Removable LCD-display diagnostic module
•Removable disk array controller module
•Removable Differential SCSI interface modules (two) with three differential
SCSI ports per module
•Removable fan tray
•Internal backplane with attached power and signal buses
•Rack-mountable chassis
1.3 General Information for SPARCstorage Array Model 100 and 200 Systems
The SPARCstorage Array connects to a host system using fibre optic cables.
These cables connect to a Fibre Channel Optical Module (FC/OM) mounted on
a Fibre Channel SBus (FC/S) card on the host system side, and to an FC/OM
mounted on the array controller on the SPARCstorage Array side.
You can have a maximum of two FC/OMs per FC/S card on the host system
side and two FC/OMs on the array controller on the SPARCstorage Array side.
Because of the number of FC/OMs available on both the host system and the
SPARCstorage Array sides, you have several hardware configuration options
when connecting a SPARCstorage Array to a server. Chapter 2, “Hardware
Configurations,” contains all the information for you to choose the hardware
configuration that best suits your needs.
The SPARCstorage Array also has storage management software which offers
several software options. Chapter 3, “Software Configurations,” contains all the
information for you to choose the software configuration that best suits your
needs.

2-1
HardwareConfigurations 2
You have several options when it comes to connecting a SPARCstorage Array
to a host system. The two factors that determine which options you should
select are:
•The number of SPARCstorage Arrays in the configuration
•The number of host systems in the configuration
When reviewing the following options, keep in mind that every SPARCstorage
Array comes standard with one FC/OM and one fibre optic cable and that
every FC/S card comes standard with one FC/OM.

2-2 SPARCstorage Array Configuration Guide—March 1995
2
2.1 Option 1
Figure 2-1 shows how you would connect the SPARCstorage Array to a host
system using this option.
Figure 2-1 Option 1 Connection
Table 2-1 Option 1
Option Hardware Needed Notes
One SPARCstorage Array on a single
host SBus slot Order: - One SPARCstorage Array
- One FC/S card
Simplest, most common configuration
FC/OM FC/SFC/OM
SPARCstorage Array
Host System

Hardware Configurations 2-3
2
2.2 Option 2
Figure 2-2 shows how you would connect the SPARCstorage Arrays to a host
system using this option.
Figure 2-2 Option 2 Connection
Table 2-2 Option 2
Option Hardware Needed Notes
Two SPARCstorage Arrays on a
single host SBus slot Order: - Two SPARCstorage Arrays
- One FC/S card
- One FC/OM
- Highest capacity per SBus slot
- Connecting 2 arrays on one SBus slot
could possibly cause the FC/S to be a
performance bottleneck on extremely
demanding sequential I/O
applications
- Lower cost than using 2 FC/S cards
for two arrays
SPARCstorage Arrays Host System
FC/OM
FC/OM
FC/SFC/OM
FC/OM

2-4 SPARCstorage Array Configuration Guide—March 1995
2
2.3 Option 3
Figure 2-3 shows how you would connect the SPARCstorage Array to the host
systems using this option.
Figure 2-3 Option 3 Connection
*. Software to control and manage this type of high availability is not supplied with the SPARCstorage Array and must be purchased separately.
†. Dual host configurations are potentially dangerous and can result in data corruption if both systems access the same disk at the same time.
Table 2-3 Option 3
Option Hardware Needed Notes
Dual-host connection to
a single SPARCstorage
Array
Order:
- One SPARCstorage
Array
- Two FC/S cards
- One FC/OM
- One fibre optic cable
Two possible reasons for this configuration:
- Static dual-porting. Two systems connect to an array, but each
disk in the array is “owned” by only one system at a time. One
host system functions as a backup for the other host. *†
- Sharing an array between two systems. Each system uses the
reserve command to reserve a subset of the disks so that the
other system is not allowed to access them. †
SPARCstorage Array
Host Systems
FC/SFC/OM
FC/SFC/OM
FC/OM
FC/OM

Hardware Configurations 2-5
2
2.4 Option 4
Figure 2-4 shows how you would connect the SPARCstorage Arrays to the host
systems using this option.
Figure 2-4 Option 4 Connection
*. Software to control and manage this type of high availability is not supplied with the SPARCstorage Array and must be purchased separately.
†. Dual host configurations are potentially dangerous and can result in data corruption if both systems access the same disk at the same time.
Table 2-4 Option 4
Option Hardware Needed Notes
Fully redundant, dual-
hosted SPARCstorage
Array
Order:
- Two SPARCstorage
Arrays
- Four FC/S cards
- Two FC/OMs
- Two fibre optic cables
- This configuration is for the highest levels of availability where
all hardware components are redundant.
- When each array is set up so that it holds a complete copy of the
data for both host system A and host system B, then any
component in either array can fail with no loss of data service to
the host systems *†
FC/OM
SPARCstorage Array A
SPARCstorage Array B
Host System A
Host System B
FC/OM
FC/OM
FC/OM
FC/SFC/OM
FC/SFC/OM
FC/SFC/OM
FC/SFC/OM
Data A, Mirrored
Data A
Data B
Data B, Mirrored

2-6 SPARCstorage Array Configuration Guide—March 1995
2

3-1
SoftwareConfigurations 3
The SPARCstorage Volume Manager software can be configured for different
levels of RAID, which stands for Redundant Array of Independent Disks.
RAID is defined as a disk array in which part of the storage capacity is used to
hold redundant information about user data that is stored on the remainder of
the disk space capacity. The redundant information enables the user data to be
regenerated if one of the array’s member disks or the access path to it fails.
Following are the data layouts offered by the SPARCstorage Volume Manager
storage management software:
•Independent disks
•RAID Level 0 (also known as striping)
•RAID Level 1 (also known as mirroring)
•RAID Level 0 + 1 (also known as mirroring striped disks)
•RAID Level 5
Note that the SPARCstorage Volume Manager storage management software
allows all these data layouts to be mixed at the same time within the same
array, with no restrictions on how the layouts are mixed and matched. These
data layouts may be spread across multiple SPARCstorage Arrays. This
flexibility allows you to configure your SPARCstorage Arrays to meet your
specific requirements.
These data layouts are explained in greater detail in the following sections.

3-2 SPARCstorage Array Configuration Guide—March 1995
3
3.1 Independent Disks
A data layout using independent disks has the following characteristics:
•Best for most applications
•No redundant data protection
•Lowest cost per usable Mbyte
3.2 Striping (RAID 0)
Striping data spreads the data out over more than one physical disk so that the
data is laid out evenly across the disks.
If you were striping data over three physical disks, the first block of data
would go on the first disk, the second block would go on the second disk, and
the third block would go on the third disk. The fourth block of data would
then go back on the first disk, the fifth block would go on the second disk, and
so on. Figure 3-1 shows how data is spread out over three disks by striping the
data.
Figure 3-1 Example of Striped Data
c2t0d0s1
c2t0d0
c1t0d0s1
c1t0d0
Physical disks
B1
B2
B3
B4
B5
B6
B = Blocks of data
B1 B4
B2 B5
B3 B6