PRIMECLUSTER Global File Services Configuration and Administration Guide 4.1 (Linux)

11.2.2 Backing up entire file system

To back up the GFS Shared File System in file system unit, use dd(1). The following describes the backing-up procedure using dd(1).

Entire-file-system backing-up allows backing-up of the entire file system more quickly than file-by-file backing-up. However, a file system backed up with this method cannot be restored on a file-by-file basis during restoring.

When you back up entire file system, please carry out in the state where the file system was unmounted.

Before executing backing-up, use the following procedure to check the partition information for the desired GFS Shared File System. Estimate the backing-up media capacity required for backing-up and the number of required media and then unmount of the GFS Shared File System.

Use sfcinfo(8) to display partition information and make it sure that tape capacity is sufficient. The partition size can be estimated by adding 1 MB to the sum of the values displayed in the size field (in kilobytes).

# sfcinfo /dev/sfdsk/gfs/dsk/volume1
FSID special                                      size  Type  mount
   1 /dev/sfdsk/gfs/dsk/volume1(e721)            12626  META   -----
   1 /dev/sfdsk/gfs/dsk/volume1(e721)             5120  LOG    -----
   1 /dev/sfdsk/gfs/dsk/volume1(e721)           113992  DATA   -----
 
# dd if=/dev/sfdsk/gfs/dsk/volume1 of=/dev/st0 bs=1024k 

 

Tapes used for data backup should be labeled for identifying the backed up partition.

 

If the file system is too large to fit on a single tape, data needs to be divided and backed up.

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

# dd if=/dev/sfdsk/gfs/dsk/volume1 of=/dev/st0 bs=1024k count=1024
  -> Tape 1
  Tape change 
# dd if=/dev/sfdsk/gfs/dsk/volume1 of=/dev/st0 bs=1024k count=1024 skip=1024
  -> Tape 2
  Tape change 
# dd if=/dev/sfdsk/gfs/dsk/volume1 of=/dev/st0 bs=1024k count=1024 skip=2048
  -> Tape 3
  Tape change 
# dd if=/dev/sfdsk/gfs/dsk/volume1 of=/dev/st0 bs=1024k count=1024 skip=3072
  -> Tape 4
    ... 

 

dd(1) does not support multi-tape volumes. If the file system is too large to fit on a single tape, data needs to be divided and backed up. In such cases, set bs (block length) and count (number of blocks) and increase skip (input-side offset (number of blocks) ) by the value of count.