backup(0) CLIX backup(0)
NAME
backup, dumpdates - Incremental dump format
SYNOPSIS
#include <sys/types.h>
#include <sys/inode.h>
#include <protocols/dumprestore.h>
DESCRIPTION
Tapes used by backup and restore contain the following:
⊕ A header record
⊕ Two groups of bit map records
⊕ A group of records describing directories
⊕ A group of records describing files
The format of the header record and the first record of each description
as given in the include file <protocols/dumprestore.h> is as follows:
#define TP_BSIZE 1024
#define NTREC 10
#define TP_NINDIR (TP_BSIZE/2)
#define TS_TAPE 1
#define TS_INODE 2
#define TS_BITS 3
#define TS_ADDR 4
#define TS_END 5
#define TS_CLRI 6
#define OFS_MAGIC (int) 60011
#define NFS_MAGIC (int) 60012
#define CHECKSUM (int) 84446
struct u_spcl {
char dummy[TP_BSIZE];
struct s_spcl {
int c_type;
time_t c_date;
time_t c_ddate;
int c_volume;
daddr_t c_tapea;
ino_t c_inumber;
int c_magic;
int c_checksum;
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backup(0) CLIX backup(0)
#ifdef FFS
struct ffsdinode c_dinode;
#else
struct dinode c_dinode;
#endif
int c_count;
char c_addr[TP_NINDIR];
} s_spcl;
} u_spcl;
#define spcl u_spcl.s_spcl
#define DUMPOUTFMT "%-20s %c %s" /* for printf */
/* name, incno, ctime(date) */
#define DUMPINFMT "%20s %c %[\n]\n" /* inverse for scanf */
NTREC is the number of 1024-byte records in a physical tape block.
TP_BSIZE is the size of file blocks on the dump tapes. NTREC is the
number of TP_BSIZE blocks written in each tape record. TP_NINDIR is the
number of indirect pointers in a TS_ADDR record. It must be a power of
two.
The TS_ entries are used in the c_type field to indicate the type of
header this is. The types and their meanings are as follows:
TS_TAPE Tape volume label.
TS_INODE A file or directory follows. The c_dinode field is a copy of
the disk inode and contains bits telling the type of file this
is.
TS_BITS A bit map follows. This bit map has a 1 bit for each inode
that was backed up.
TS_ADDR A subrecord of a file description. See c_addr below.
TS_END End-of-tape record.
TS_CLRI A bit map follows. This bit map contains a zero bit for all
inodes that were empty on the file system when backed up.
MAGIC All header records have this number in c_magic. OFS_MAGIC is
the old file system magic number. NFS_MAGIC is the new file
system magic number.
CHECKSUM Header records checksum to this value.
The fields of the header structure are as follows:
c_type The type of the header.
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backup(0) CLIX backup(0)
c_date The date the backup was taken.
c_ddate The date the file system was backed up from.
c_volume The current volume number of the backup.
c_tapea The current number of this (1024-byte) record.
c_inumber The number of the inode being backed up if this has type
TS_INODE.
c_magic The value NFS_MAGIC above, truncated as needed.
c_checksum The value needed to make the record sum to CHECKSUM.
ic_dinode A copy of the inode as it appears on the file system.
c_count The count of characters in c_addr.
c_addr An array of characters describing the blocks of the backed up
file. A character is zero if the block associated with that
character was not present on the file system. Otherwise, the
character is nonzero. If the block was not on the file
system, no block was backed up; the block will be restored as
a hole in the file. If space in this record is not
sufficient to describe all blocks in a file, TS_ADDR records
will be scattered through the file, each picking up where the
last left off.
Each volume except the last ends with a tape mark (read as an end-of-
file). The last volume ends with a TS_END record and then the tape mark.
The structure idates describes an entry in the file /etc/dumpdates where
backup history is kept.
struct idates {
char id_name[16];
char id_incno;
time_t id_ddate;
};
The fields of the structure are as follows:
id_name The dumped file system is /dev/dsk/s?u?p?.?.
id_incno The level number of the dump tape; see backup.
id_ddate The date of the incremental backup.
FILES
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backup(0) CLIX backup(0)
/etc/dumpdates
RELATED INFORMATION
Commands: backup(8), restore(1)
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