AIX allows users to configure tape devices for either fixed or variable length block mode. Sybase IQ BACKUP only supports variable-length devices.
You can use the following command to display the block mode for a tape device:
% mt -f <tape device> status
For example:
mt -f /dev/rmt0.1 status
rmt0 Available 00-07-A1-1,0 5.0 GB 8mm Tape Drive attribute value description user_settable mode yes Use DEVICE BUFFERS during writes True block_size 0 BLOCK size (0=variable length) True extfm no Use EXTENDED file marks True density_set_1 140 DENSITY setting #1 True density_set_2 20 DENSITY setting #2 True compress yes Use data COMPRESSION True
Note that the value for block_size is 0. This tape drive is in variable-length block mode. A non-zero value indicates fixed length block mode, which IQ backup does not support.
To change the block mode, you will need root access. Use SMIT to display and change the current block mode of any tape device that you plan to use for backups.
To change the current block mode using SMIT:
Select the Devices option from the System Management menu.
Select the Tape Drive option.
Select the Change/Show Characteristics of Tape Drive option.
Select the tape device. SMIT shows characteristics, including the current block size.
Type a new value in the BLOCK size Entry Field and press Enter.
