Sparcstorage Array Configuration Guide

SPARCstorage Array Conﬁguration Guide

A Sun Microsystems, Inc. Business 2550 Garcia Avenue Mountain View, CA 94043 U.S.A. 415 960-1300 FAX 415 969-9131 Part No.: 802-2041-10 Revision A, March 1995  1995 Sun Microsystems, Inc. 2550 Garcia Avenue, Mountain View, California 94043-1100 U.S.A. All rights reserved. This product and related documentation are protected by copyright and distributed under licenses restricting its use, copying, distribution, and decompilation. No part of this product or related documentation may be reproduced in any form by any means without prior written authorization of Sun and its licensors, if any. Portions of this product may be derived from the UNIX® and Berkeley 4.3 BSD systems, licensed from UNIX System Laboratories, Inc., a wholly owned subsidiary of Novell, Inc., and the University of California, respectively. Third-party font software in this product is protected by copyright and licensed from Sun’s font suppliers. RESTRICTED RIGHTS LEGEND: Use, duplication, or disclosure by the United States Government is subject to the restrictions set forth in DFARS 252.227-7013 (c)(1)(ii) and FAR 52.227-19. The product described in this manual may be protected by one or more U.S. patents, foreign patents, or pending applications. TRADEMARKS Sun, the Sun logo, Sun Microsystems, Solaris, are trademarks or registered trademarks of Sun Microsystems, Inc. in the U.S. and certain other countries. UNIX is a registered trademark in the United States and other countries, exclusively licensed through X/Open Company, Ltd. OPEN LOOK is a registered trademark of Novell, Inc. PostScript and Display PostScript are trademarks of Adobe Systems, Inc. All other product names mentioned herein are the trademarks of their respective owners. All SPARC trademarks, including the SCD Compliant Logo, are trademarks or registered trademarks of SPARC International, Inc. SPARCstation, SPARCserver, SPARCengine, SPARCstorage, SPARCware, SPARCcenter, SPARCclassic, SPARCcluster, SPARCdesign, SPARC811, SPARCprinter, UltraSPARC, microSPARC, SPARCworks, and SPARCompiler are licensed exclusively to Sun Microsystems, Inc. Products bearing SPARC trademarks are based upon an architecture developed by Sun Microsystems, Inc. The OPEN LOOK® and Sun™ Graphical User Interfaces were developed by Sun Microsystems, Inc. for its users and licensees. Sun acknowledges the pioneering efforts of Xerox in researching and developing the concept of visual or graphical user interfaces for the computer industry. Sun holds a non-exclusive license from Xerox to the Xerox Graphical User Interface, which license also covers Sun’s licensees who implement OPEN LOOK GUIs and otherwise comply with Sun’s written license agreements. X Window System is a product of the Massachusetts Institute of Technology. THIS PUBLICATION IS PROVIDED “AS IS” WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT. THIS PUBLICATION COULD INCLUDE TECHNICAL INACCURACIES OR TYPOGRAPHICAL ERRORS. CHANGES ARE PERIODICALLY ADDED TO THE INFORMATION HEREIN; THESE CHANGES WILL BE INCORPORATED IN NEW EDITIONS OF THE PUBLICATION. SUN MICROSYSTEMS, INC. MAY MAKE IMPROVEMENTS AND/OR CHANGES IN THE PRODUCT(S) AND/OR THE PROGRAM(S) DESCRIBED IN THIS PUBLICATION AT ANY TIME.

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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

iii 3.6 Determining Which RAID Level to Use ...... 3-6 3.7 Other Facts on RAID and the SPARCstorage Array . . . . 3-7

iv SPARCstorage Array Conﬁguration Guide—March 1995 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

v vi SPARCstorage Array Conﬁguration Guide—March 1995 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

vii viii SPARCstorage Array Conﬁguration Guide—March 1995 Product Description 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

1-1 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)

Fan tray Array controller

Power supply

Backplane

Drive tray

Figure 1-2 Internal Components

1-2 SPARCstorage Array Conﬁguration Guide—March 1995 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.

Fan tray

Power supply

Diagnostic module

Controller

Differential SCSI interface

Figure 1-3 SPARCstorage Array Model 200 Series Subsystem

Product Description 1-3 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.

1-4 SPARCstorage Array Conﬁguration Guide—March 1995 Hardware Conﬁgurations 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.

2-1 2

2.1 Option 1

Table 2-1 Option 1

Option Hardware Needed Notes One SPARCstorage Array on a single Order: Simplest, most common conﬁguration host SBus slot - One SPARCstorage Array - One FC/S card

Figure 2-1 shows how you would connect the SPARCstorage Array to a host system using this option.

Host System SPARCstorage Array

FC/OM FC/OM FC/S

Figure 2-1 Option 1 Connection

2-2 SPARCstorage Array Conﬁguration Guide—March 1995 2

2.2 Option 2

Table 2-2 Option 2

Option Hardware Needed Notes Two SPARCstorage Arrays on a Order: - Highest capacity per SBus slot single host SBus slot - Two SPARCstorage Arrays - One FC/S card - Connecting 2 arrays on one SBus slot - One FC/OM 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

Figure 2-2 shows how you would connect the SPARCstorage Arrays to a host system using this option.

SPARCstorage Arrays Host System

FC/OM FC/OM FC/S

FC/OM

Figure 2-2 Option 2 Connection

Hardware Conﬁgurations 2-3 2

2.3 Option 3

Table 2-3 Option 3

Option Hardware Needed Notes Dual-host connection to Order: Two possible reasons for this conﬁguration: a single SPARCstorage - One SPARCstorage - Static dual-porting. Two systems connect to an array, but each Array Array disk in the array is “owned” by only one system at a time. One - Two FC/S cards host system functions as a backup for the other host. *† - One FC/OM - One ﬁbre optic cable - 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. †

*. 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.

Figure 2-3 shows how you would connect the SPARCstorage Array to the host systems using this option.

Host Systems

FC/OM FC/S SPARCstorage Array

FC/OM FC/OM

FC/OM FC/S

Figure 2-3 Option 3 Connection

2-4 SPARCstorage Array Conﬁguration Guide—March 1995 2

2.4 Option 4

Table 2-4 Option 4

Option Hardware Needed Notes Fully redundant, dual- Order: - This conﬁguration is for the highest levels of availability where hosted SPARCstorage - Two SPARCstorage all hardware components are redundant. Array Arrays - Four FC/S cards - When each array is set up so that it holds a complete copy of the - Two FC/OMs data for both host system A and host system B, then any - Two ﬁbre optic cables component in either array can fail with no loss of data service to the host systems *†

Figure 2-4 shows how you would connect the SPARCstorage Arrays to the host systems using this option.

Host System A SPARCstorage Array A

Data A FC/OM FC/OM FC/S

Data B, Mirrored FC/OM

FC/OM FC/S

Host System B SPARCstorage Array B

FC/OM FC/S Data A, Mirrored FC/OM

Data B FC/OM FC/OM FC/S

Figure 2-4 Option 4 Connection

Hardware Conﬁgurations 2-5 2

2-6 SPARCstorage Array Conﬁguration Guide—March 1995 Software Conﬁgurations 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.

3-1 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.

Physical disks B = Blocks of data B1

B1 B4 B2

c1t0d0s1 B2 B5 B4 c1t0d0

B3 B6 c2t0d0s1 B6 c2t0d0

Figure 3-1 Example of Striped Data

3-2 SPARCstorage Array Conﬁguration Guide—March 1995 3

A data layout using striping has the following characteristics: • Spreads data across multiple disk spindles for better performance • Can be tuned to optimize either random or sequential I/O performance • No redundant data protection, lower reliability than independent disks • Same low cost per usable Mbyte as independent disks

3.3 Mirroring (RAID 1)

Mirroring data copies the same data onto two or more separate physical disk drives. This is useful if you want to make sure data is available even if one physical disk fails; the data can be retrieved from the other physical disk that has the copy of the original data. In addition, it can sometimes improve read performance on busy data sets.

If you were mirroring data to two physical disks, you would send the same data to both disks. Figure 3-2 shows how data would be mirrored to two physical disks.

Physical disks B = Blocks of data

B1 B2 B3 B1

c1t0d0s1 c1t0d0 B1 B2 B3

Figure 3-2 Example of Mirrored Data

A data layout using mirroring has the following characteristics: • Duplicate copies of data, so if a disk fails, data is still available and applications keep running • Performance roughly the same as independent disks • Highest cost per usable Mbyte

Software Conﬁgurations 3-3 3

3.4 Mirroring Striped Disks (RAID 0 + 1)

Mirroring striped disks consists of two separate operations:

1. Data is striped across several physical disks.

2. The data from the striped disks is mirrored on separate physical disks.

This is useful if you want to get data written to or read from physical disks quickly and also want to make sure that data is available even if a disk fails.

Figure 3-3 shows how you would stripe and mirror data over four physical disks.

B = Blocks of data Physical disks B1

B1 B3 B2

Striping B3

c1t0d0s1 B2 B4

c1t0d0 B4

B1 B3 c2t0d0s1 c2t0d0

Mirroring

B2 B4 c3t0d0s1 c3t0d0

Figure 3-3 Example of Mirroring Striped Data

3-4 SPARCstorage Array Conﬁguration Guide—March 1995 3

A data layout using mirroring striped disks has the following characteristics: • Duplicated copies of striped data remain available even if a disk fails • Combines performance of striping with data protection of mirroring • Has cost per usable Mbyte disadvantages of mirroring

3.5 RAID 5

A RAID 5 configuration is similar to a striped configuration in that data is spread out evenly across several disks in a system. However, a RAID 5 configuration adds a parity block to the stripe to provide redundancy. This parity block contains the result of an exclusive OR (XOR) procedure done on the data in the data stripes. If the data on one of the disks in the RAID 5 configuration becomes inaccessible due to a hardware or software failure, data can be restored by XORing the contents of the remaining data disks with the parity disk. The data on the failed disk can be rebuilt from the output of the XOR process.

When a write is performed on disks set up in a RAID 5 configuration, the data is written to all but one of the disks; the remaining disk then gets the parity information written to it. The next write performed on the disks in a RAID 5 configuration would work the same way, except that the parity information would be written to a different disk than that used in the first write. That way, the parity information gets spread across all the disks in the configuration, so that if one disk fails, the data from that disks can be restored using the parity information written on the remaining disks in the configuration.

For example, if three disks were used in a RAID 5 configuration, data written to those disks in this manner: for the first set of writes, data would be written to the first two disks in the configuration and the parity information would be written to the third disk. On the second set of writes to the disks, the data would be written to the first and third disks, and the parity information would be written to the second. On the third set of writes, the data would be written to the second and third disks, and the parity information would be written to the first. The fourth write would be performed as the first write was, with data on the first and second disks and parity information on the third. Figure 3-4 shows how RAID 5 information would be written to disks using this setup.

Software Conﬁgurations 3-5 3

D D P D P D P D D D D P

D = Data Stripe Unit P = Parity Stripe Unit

Figure 3-4 Graphical Representation of RAID 5 Writes

A data layout using RAID 5 has the following characteristics: • Spreads data across multiple disk spindles for better performance • Data remains available even if a disk fails because of parity • Slightly higher cost per usable Mbyte as independent disks or striping

3.6 Determining Which RAID Level to Use

The different RAID levels have varying degrees of beneﬁts and liabilities in each of the following areas: • Cost — number of disks required • Data reliability — ability to get data even if disk fails • Data transfer capacity — ability to move large amounts of sequential access data rapidly • I/O rate — ability to satisfy large numbers of random I/O requests per unit time

3-6 SPARCstorage Array Conﬁguration Guide—March 1995 3

Refer to Table 3-1 for to determine which RAID level best suits your needs.

Table 3-1 Comparisons of RAID Levels

➊ — much better than single disk ➌ — equal to single disk ➍ — slightly worse than single disk ➋ — slightly better than single disk ➎ — much worse than single disk Data transfer capacity I/O Rate RAID Data Levels Cost Reliability Writing Data Reading Data Write Read 0 ➌➎➊➊➊➊ 1 ➎➊➍➋➍➋ 0 + 1 ➎➊➊➊➊➊ 5 ➍➊➊➊➊➊

3.7 Other Facts on RAID and the SPARCstorage Array • You can use any combination of independent disks or disks using RAID levels 0, 1, 0 + 1, or 5 in the same array. • RAID groups may even span multiple arrays. • Optional hot spares are automatically swapped in to replace any failed disk in a RAID 0 + 1 or 1 group without human intervention. Hot spares are extra disk drives in the array that are powered up and ready to use. If a drive in a RAID 0 + 1 or 1 group fails, the Volume Manager detects the failure and automatically rebuilds the data from the failed drive onto a hot spare drive. • There can be one or more hot spares per array. A hot spare drive can be tied to one or more particular drives, one or more particular RAID groups, or may be designated as a spare for any drive in any RAID group. • The combination of hot spares with warm pluggability provides new levels of high availability and administrative ﬂexibility. Hot spares allow maintenance to be deferred for long periods of time and warm pluggability means that the array downtime is very short when a failed drive is eventually changed. • Since RAID is not ideal for many situations, the SPARCstorage Array allows you to conﬁgure disk drives as regular, independent disks, rather than forcing you to use RAID.

Software Conﬁgurations 3-7 3

• RAID stripe sizes are adjustable to optimize for either random or sequential I/O patterns. • Striped data organizations (RAID 0, 0 + 1 and 5) can be tuned to optimize for either random or sequential I/O performance. • To optimize for random performance, striping is used to evenly balance the I/O load across disk spindles in the RAID. This is done by setting the stripe width as large or larger than the typical application I/O request. For example, if the typical I/O request is 8 Kbytes, setting the stripe width to 64 Kbytes might be appropriate. This tends to evenly distribute I/O request across all the disk drives in the RAID, and each I/O request is serviced by a single disk drive. • Sequential performance is optimized when data is spread out so that each application I/O request spans all the drives in the RAID group. This requires setting the stripe width so that it is small relative to the size of the typical I/O request. For example, in a RAID group four data disks wide, if typical application I/O size is 8 to 16 Kbytes, a stripe width of 2 Kbytes may be best.

3-8 SPARCstorage Array Conﬁguration Guide—March 1995 Index

A H array controller, location, 1-2 hardware conﬁgurations considerations, 2-1 for single host SBus slot, 2-2, 2-3 B for single host system, 2-2, 2-3 backplane, location, 1-2 for single SPARCstorage Array, 2-2, battery module, location, 1-2 2-4 for two host systems, 2-4, 2-5 D for two SPARCstorage Arrays, 2-3, 2- 5 drive trays, location, 1-2 full redundancy, 2-5 highest capacity per SBus slot, 2-3 F sharing one array between two hosts, 2-4 fan tray, location, 1-2 simplest, most common, 2-2 FC/OM, see Fibre Channel Optical static dual-porting, 2-4 Module hot spares, 3-7 FC/S, see Fibre Channel Sbus card Fibre Channel Optical Module location, 1-2 M maximum number per FC/S, 1-4 mirroring striped disks, see RAID level 0 + maximum number per SPARCstorage 1 Array, 1-4 mirroring, see RAID level 1 Fibre Channel SBus card, standard package, 2-1 P parity, 3-5 power supply, location, 1-2

Index-1 R RAID considerations cost, 3-6 data reliability, 3-6 data transfer capacity, 3-6 I/O rate, 3-6 deﬁnition, 3-1 determining which level to use, 3-6 level 0 + 1, description, 3-4 level 0, description, 3-2 level 1, description, 3-3 level 5, description, 3-5 Redundant Array of Independent Disks, see RAID

S SPARCstorage Array internal components, 1-2 product description, 1-1 standard package, 2-1 striping, see RAID level 0

W warm pluggability, 3-7

X XOR, 3-5

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