dd备份文件有大小限制吗

didikei

AIX4.3.3
裸设备文件:/dev/tmpa(文件大小:20G)
3590流带:/dev/rmt0
命令行:dd if=/dev/tmpa of=/dev/rmt0 bs=2048k

出错信息如下:
dd: 0511-051 The read failed.
: There is an input or output error.
8000+0 records in.
8000+0 records out.

问题:
是因为dd对文件有限制吗
怎么解决这个问题

ewhisper

0511-051 The read failed
Possible Causes
The tape is backed up on a tape device with a block size that differs from the one on which it is currently set.
The value specified with either the bs, ibs, or obs flag is not a multiple of the block size of the tape device.
The value specified for the fskip flag is greater than the number of end-of-file marks on the tape.
The tape is damaged.
Procedures for Recovery
Use the chdev command to change the block size on the tape device:
chdev -1 rmt# -a block size=0
Use the tctl command to check the block size of the tape device:
tctl -f /dev/rmt# status
Then, specify the value of the bs, ibs, or obs flag as a multiple of the block size.
Use the tcopy command to check the number of files or records that can be accessed on tape.
Check the error log for tape errors:
errpt -a