AIX: COPYING RAW DEVICE TO FILE SYSTEM USING DD COMMAND (문서 ID 1027958.6)

AIX: COPYING RAW DEVICE TO FILE SYSTEM USING DD COMMAND (문서 ID 1027958.6) Problem Description: ====================== How to backup the database on the raw device to the filesystem using 'dd'. Solution Description: ===================== The following commands will allow you to copy a raw device to the filesystem and restore from the filesystem to the raw device. You must use the dd command to copy from the raw device. Please Note: ============ 1. Caution is required because some AIX backup programs ignore large files; you must verify that any oversized AIX files are indeed backed up. 2. When doing copy/backup operations, please consider the 4KB offset (taken by Oracle) for the Logical Volume Control Block(LVCB) at the beginning of all IBM Virtual Shared Disks when performing backup/restore operations. 3. When using zero offset raw devices (devices created using: # mklv -T O -y new_raw_device VolumeGroup NumberOfPartitions), ensure the 'skip' parameter is adjusted accordingly. The offset can be 4096 bytes or 128 KB on AIX logical volumes or zero on AIX logical volumes created with the mklv -T O option. Copying to Filesystem -------------------------- Use the command: % dd if=<raw device name> of=<filesystem name> bs=<BlockSize> skip=<SkipInputBlocks> Example: % dd if=/dev/rVh09.za.716c1 of=/a/spdevs04/ibmfs/osupport/dismith/test.ctl bs=4096 skip=1 In the above example we specify the blocksize as 4096 bytes and skip 1 block for the offset for the Logical Volume Control Block(LVCB) bs=BlockSize - Specifies both the input and output block size, superceding the ibs and obs flags. The block size values specified with the bs flag must always be a multiple of the physical block size for the media being used. skip=SkipInputBlocks - Skips the specified SkipInputBlocks value of input blocks before starting to copy. Restoring from Filesystem -------------------------- Use the command: % dd if=/a/spdevs04/ibmfs/osupport/dismith/test.ctl of=/dev/rVh09.za.716c1 bs=4096 seek=1 In the above example we specify the blocksize as 4096bytes and seek 1 block past the beginning of output file before copying, so we will not overwrite the Logical Volume Control Block(LVCB) seek=RecordNumber - Seeks the record specified by the RecordNumber variable from the beginning of output file before copying.