PRIMECLUSTER Global File Services Configuration and Administration Guide 4.2 (Solaris(TM) Operating Environment)

24.4.2 Backing up an entire file system

To back up the GFS Shared File System, use dd(1M). The following describes the backup procedure for using dd(1M).

Entire file system backups are faster than file by file backups. However, a file system backed up with this method cannot be restored on a file by file basis.

Before starting a backup, use the following procedure to check the partition information for the desired GFS Shared File System. Estimate the backup capacity required including the number of physical media required and then unmount the GFS Shared File System.

• For a single partition configuration

  Use sfcinfo(1M) to display partition information and check that the file system has only a single partition (same special file names) and that the capacity of the tape is sufficient. The size of the partition can be estimated by adding 1 MB to the sum of the values displayed in the size field (in kilobytes).

  Example: In the following example, a file system with a single partition configuration is backed up.

# sfcinfo /dev/sfdsk/gfs/dsk/volume1
FSID special                                     size  Type  mount
   1 /dev/sfdsk/gfs/dsk/volume1(3fa0081)        12626  META  /mnt
   1 /dev/sfdsk/gfs/dsk/volume1(3fa0081)       113992  DATA  /mnt
   1 /dev/sfdsk/gfs/dsk/volume1(3fa0081)         5120  LOG   /mnt


# dd if=/dev/sfdsk/gfs/rdsk/volume1 of=/dev/rmt/0 bs=1024k

• For a multi-partition configuration

  dd(1M) can handle one partition at a time. For a multi-partition configuration, therefore, the partitions must be backed up one at a time. Use sfcinfo(1M) to check the partition configuration then backup each partition with the same procedure as used for a single partition configuration.

  Example: In the following example, a file system with three partitions (log area separation + data area addition) is backed up.

# sfcinfo /dev/sfdsk/gfs/dsk/volume1
FSID special                                     size  Type  mount
   1 /dev/sfdsk/gfs/dsk/volume1(3fa0081)        25986  META  /mnt
   1 /dev/sfdsk/gfs/dsk/volume1(3fa0081)       105751  DATA  /mnt
   1 /dev/sfdsk/gfs/dsk/volume2(3fa0082)         5120  LOG   /mnt
   1 /dev/sfdsk/gfs/dsk/volume3(3fa0083)       131736  DATA  /mnt


# dd if=/dev/sfdsk/gfs/rdsk/volume1 of=/dev/rmt/0 bs=1024k -> Tape 1
  Tape change
# dd if=/dev/sfdsk/gfs/rdsk/volume2 of=/dev/rmt/0 bs=1024k -> Tape 2
  Tape change
# dd if=/dev/sfdsk/gfs/rdsk/volume3 of=/dev/rmt/0 bs=1024k -> Tape 3

• All the partitions making up the desired GFS Shared File System must be backed up. Avoid backing up and storing only some of the partitions.
• The tapes used for backups must be labeled so that the backed up partitions can be identified. They must then be stored as a set.

dd(1M) does not support multi-tape volumes. If the file system is too large to fit on a single tape, it must be backed up as separate blocks. To do this, set bs (block length) and count (number of blocks) and increase iseek (input-side offset (number of blocks) by the value of count).

Example: In the following example, a partition is backed up in 1 GB units.

# dd if=/dev/sfdsk/gfs/rdsk/volume1 of=/dev/rmt/0 bs=1024k count=1024
  -> Tape 1
  Tape change
# dd if=/dev/sfdsk/gfs/rdsk/volume1 of=/dev/rmt/0 bs=1024k count=1024 iseek=1024
  -> Tape 2
  Tape change
# dd if=/dev/sfdsk/gfs/rdsk/volume1 of=/dev/rmt/0 bs=1024k count=1024 iseek=2048
  -> Tape 3
  Tape change
# dd if=/dev/sfdsk/gfs/rdsk/volume1 of=/dev/rmt/0 bs=1024k count=1024 iseek=3072
  -> Tape 4
    ...