If your system uses System V shared memory (your system administrator can tell you if it does), then depending on the constraints of the archive device driver, using double buffering (the -D option) can sometimes show a dramatic increase in the I/O rate of the archive device. It is not uncommon to see the speed increase by a factor of two. Unfortunately, it is also not uncommon to see the speed decrease slightly also. This feature is very hardware and software dependent, and the only way to discover if you should use it for a particular device is to try it and see if it helps.
ArGest Backup User Guide
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- What is ArGest Backup?
- General Notes
- Device Compatibility
- Performance
- Platform and Version Compatibility
- A Word About Capacity and Compression
- Fast Recovery
- Recover to an Alternate Location
- The BRU Tape Format
- Verify Capabilities
- Special Files
- File Comparisons
- File Restore Overwrite Protection
- Catalogs – What Are They?
- Archival Versus Backup
- Tape Data Protection Options
- Definitions and Concepts
- Important Backup Data Selection Concepts
- Installation, Licensing, QuickStart
- Advanced Terminal Operation
- The brutab File
- Terminal Archive Creation: The Backup Function
- Overview
- The BRU Command Line
- Command Line Options: Modes
- Telling BRU This Is a Backup (-c)
- Estimating Archive Size (-e)
- Command Line Options: Control Options
- Telling BRU What Device to Use: (-f device)
- Labeling the Archive: (-L) label
- Backing up Raw devices: (-r)
- Changing Default BRU Operations With: (-Q)
- Selection Depth for Backup: (-U)
- Setting the Verbosity Level: (-v and -V)
- Generating Log Files Using: (-v lower case v)
- Confirmation Option: (-w)
- Do Not Cross Mount Points: (-m)
- Excluding Remote Files: (-R)
- Running Without User Intervention: (-B)
- Specifying Media Size: (-s media_size)
- Data Compression: (-Z)
- Command Line Options: File Selection
- Using Wildcard Filename Expansion
- Using Pathnames
- Selecting Files from stdin: (-)
- Selecting Files by Date: (-n date)
- Date Formats for Use with (-n)
- Resetting Access Time: (-a)
- Inverse Date Specification
- Selecting Files by User: (-o)
- Selecting Files by User Name: (-o login_name)
- Selecting Files by File Owner: (-o pathname)
- Selecting Files by User ID: (-o decimal_value)
- Forcing Overwrite of Archives (OVERWRITEPROTECT): (-O)
- The Shell Scripts fullbru and incbru
- Interrupting BRU
- Terminal File Inclusion and Exclusion
- Terminal Archive Inspection and Verification
- Overview
- Archive Inspection
- Inspecting an Archive: (-i)
- Listing the Table of Contents: (-t)
- Dumping the Archive Information Block: (-g)
- Archive Verification
- Archive Verification – Reporting File Differences: (-d)
- Difference Mode Examples
- Using BRU To Find System Problems
- AUTOSCAN Verification
- When AUTOSCAN Is Disabled
- Terminal Extract Files: The Restore Function
- Overview
- The BRU Command Line
- Command Line Options: Modes
- Telling BRU To Restore: (-x)
- Command Line Options: Control Options
- Telling BRU What Device to Use: (-f device)
- Setting the Verbosity Level: (-v)
- Generating Log Files: (-v)
- Label Option: (-L)
- Command line override option: (-Q)
- Depth Selection on Restore Option: (-U)
- Confirmation Option: (-w)
- Changing Ownership of Extracted Files: (-C)
- Command Line Options: File Selection
- Using Wildcard File Name Expansion
- Using Include/Exclude Patterns
- Unconditional File Type Extraction: (-u flag)
- The -E File Extraction Option
- Extracting Filenames Read from stdin: –
- Extracting Files by Date: (-n date)
- Inverse Date Specification
- Extracting Files by User: (-o)
- Extracting Files by User Name: (-o username)
- Extracting Files by User ID: (-o uid)
- Extracting Files by File Owner: (-o pathname)
- Where To Put the Files: Pathnames
- Translate on Restore Option: (-T file)
- Converting Pathnames from Absolute to Relative Form: (-PA)
- Terminal Advanced Uses
- Overview
- Telling BRU the Buffer Size: (-b bufsize)
- Setting the Archive Media Size: (-s msize)
- Reading stdin or Writing stdout (standard I/O streams)
- Using Multiple Files/Devices: (-f device)
- Ownership of Extracted Files: (-C)
- Increasing BRU’s Speed
- Specifying a Larger (or Smaller) Buffer Size
- Available memory size
- Device limitations
- Improperly specified size
- Archive header information
- Double Buffering: (-D)
- Turning Off Error Checking: (-F)
- Using Data Compression: (-Z)
- Using An Alternate Compressor With BRU
- Using BRU with brutalk: (-I args)
- Running BRU from cron
- Setting Up a cron Entry
- BRU’s I/O Streams
- Handling Sparse Files: (-S threshold)
- Using Remote Devices (non-OS X)
- Restoring Shared Library Files – SmartRestore
- Appending to Existing Archives
- Live Systems Backups
- Appendix
- Appendiz A – Files That Are Installed
- Appendix B – The BRU Help Command
- Appendix C – The BRU Manual Page
- Appendix D – Table of BRU Modes and Options
- Appendix E – Sample BRUTAB File
- Appendix F – BRU Execution Log
- Appendix G – The Shell Scripts: fullbru and incbru
- Appendix H – The brutalk Program
- Appendix I – The brutalk File
- Appendix J – Advanced BRUTAB Settings
- Appendix K – Using MOUNTCMD and UNMOUNTCMD
- Appendix L – BRU Messages
- ArGest Backup License Agreement
- Home
- Docs
- ArGest Backup User Guide
- Terminal Advanced Uses
- Double Buffering: (-D)