Copying UFS Files and File Systems (Tasks)
This chapter describes how to copy UFS files and file systems to disk, tape, and diskettes by using various backup commands.
This is a list of the step-by-step instructions in this chapter.
Commands for Copying File Systems
When you need to back up and restore complete file systems, use the ufsdump and ufsrestore commands described in Chapter 49, UFS Backup and Restore Commands (Reference). When you want to copy or move individual files, portions of file systems, or complete file systems, you can use the procedures described in this chapter as an alternative to the ufsdump and ufsrestore commands.
Table 50-1 When to Use Various Backup Commands
For More Information
Back up file systems to tape
Create a file system snapshot
Restore file systems from tape
Transport files to other systems
pax, tar, or cpio
Copy files or file systems between disks
Copy files to diskette
The following table describes various backup and restore commands.
Table 50-2 Summary of Various Backup Commands
Aware of File System Boundaries?
Support Multi Volume Backups?
Physical or Logical Copy?
The following sections describe the advantages and disadvantages of each method, and provide step-by-step instructions and examples of how to use the commands.
Copying File Systems Between Disks
Two commands are used to copy file systems between disks:
The next section describes how to use the dd command to copy file systems between disks.
Making a Literal File System Copy
Note - Do not use the dd command with variable-length tape drives without first specifying an appropriate block size.
You can specify a device name in place of standard input or standard output, or both. In this example, the contents of the diskette are copied to a file in the /tmp directory:
$ dd < /floppy/floppy0 > /tmp/output.file 2400+0 records in 2400+0 records out
The dd command reports on the number of blocks it reads and writes. The number after the + is a count of the partial blocks that were copied. The default block size is 512 bytes.
The dd command syntax is different from most other commands. Options are specified as keyword=value pairs, where keyword is the option you want to set and value is the argument for that option. For example, you can replace standard input and standard output with this syntax:
$ dd if=input-file of=output-file
To use the keyword=value pairs instead of the redirect symbols in the previous example, you would type the following:
$ dd if=/floppy/floppy0 of=/tmp/output.file