File System Administration 2550 Garcia Avenue Mountain View, CA 94043 U.S.A. A Sun Microsystems, Inc. Business 1994 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. 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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. Please Recycle Contents Preface. xix Part 1 —Administering File Systems 1. Planning File Systems . 1 Types of File Systems. 2 Disk-Based File Systems . 3 Network-Based File Systems . 3 Pseudo File Systems . 4 File System Administration Commands. 7 Syntax of Generic Commands . 8 Manual Pages for Generic and Specific Commands . 9 How the File System Commands Determine the File System Type. 9 How to Find Out the Type of a File System . 9 The Default SunOS File Systems . 12 Understanding Disk Device Names . 13 Understanding the UFS File System . 13 iii Disk Slices . 14 Cylinder Groups . 19 Planning UFS File Systems . 19 File System Parameters . 20 Making File Systems Available . 21 Understanding Mounting and Unmounting . 22 The Automounter . 29 Sharing Files From a Server . 29 2. Creating File Systems. 35 Creating a UFS File System on a Disk Slice . 35 Preparing to Create a UFS File System . 36 Installing a Boot Block on a UFS File System. 37 Creating a File System on a Diskette . 37 Creating a Temporary File System (TMPFS) . 38 Creating a Loopback File System. 39 3. Mounting and Unmounting File Systems . 41 Finding Out Which File Systems Are Mounted . 41 Creating Entries in the File System Table . 42 Mounting File Systems in the File System Table . 45 Mounting File Systems From the Command Line. 47 Unmounting File Systems. 53 Sharing File Systems . 55 Examples of Automatic Sharing Entries in the /etc/dfs/dfstab File . 56 iv File System Administration—August 1994 4. Copying UFS Files and File Systems. 57 Commands for Copying File Systems. 58 Copying Complete File Systems . 58 Using the labelit and volcopy Commands . 59 Using the dd Command . 63 Using the cpio Command . 64 Copying Files and File Systems to Tape . 65 Useful Commands for Streaming Tape Cartridges . 65 Using the tar Command . 67 Using the cpio Command . 69 Copying Files and File Systems to Diskette . 72 Copying Files with a Different Header Format . 76 Retrieving Files Created With the bar Command. 77 5. The Cache File System . 79 Cache File System Concepts . 79 Resource Management . 80 Front File System Requirements . 80 Setting Up a Cached File System . 80 Administering a Cache . 81 Creating a Cache . 81 Cache Parameters . 81 Setting Cache Parameters . 83 Modifying Parameters. 84 Displaying Information About Cached File Systems . 85 Contents v Deleting Cached File Systems . 86 Mounting a Cached File System. 86 Using mount to Mount a Cached File System . 87 Creating a vfstab Entry for Cached File Systems . 91 Checking a Cached File System . 91 Part 2 —Backup and Restore 6. Planning a Backup Strategy . 95 Why You Back Up File Systems . 95 Understanding the ufsdump Command . 96 Advantages of ufsdump . 96 Disadvantages of ufsdump . 97 How ufsdump Works . 97 Choosing Which File Systems to Back Up . 99 File Systems to Back Up on a Standalone System . 100 File Systems to Back Up on a Server . 100 Choosing Which Media to Use. 102 Backup Device Names. 103 Guidelines for Drive Maintenance and Media Handling. 107 Considering Other Issues . 108 When to Run Backups. 108 How Long to Save Backups . 109 How to Back Up Files to a Remote Drive . 109 Do You Need to Become Superuser?. 110 Should You Check File Systems Before a Full Backup? . 110 vi File System Administration—August 1994 Do You Want to Put Multiple Backups on the Same Tape? 111 Where Do the Files Reside? . 111 How Do You Backup on a Heterogeneous Network? . 111 What Are the Security Issues? . 112 Planning a Backup Schedule . 112 7. Backing Up Files and File Systems . 121 Preparing to Do Backups . 121 Doing Complete Backups . 126 Doing Incremental Backups . 128 Backing Up Individual Files and Directories . 128 Using a Remote Drive to Do Backups . 128 Doing Backups on Remote Systems . 130 Troubleshooting When the Root File System Fills Up. 130 Options and Arguments for the ufsdump Command. 131 Default Command Options . 132 Options for the ufsdump Command. 132 8. Restoring Files and File Systems . 139 Preparing to Restore Files and File Systems. 139 Determining Which Tapes to Use . 140 Determining the Disk Device Name . 141 Determining the Type of Tape Drive You Will Use . 142 Determining the Tape Device Name . 142 Restoring Complete File Systems. 142 Synopsis of Steps ..