Corrupt block message in alert log

Recently, we found the following message appearred in our alert_<SID>.log file.

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Corrupt block relative dba: 0x1e403ac6 file=121. blocknum=15046. Fractured block found during direct read Data in bad block - type:8. format:2. rdba:0x1e403ac8 last change scn:0x0000.382b9618 seq:0x1 flg:0x08 consistancy value in tail 0x96840801
check value in block header: 0x0, check value not calculated spare1:0x0, spare2:0x0, spare2:0x0
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Corrupt block relative dba: 0x1e403ac8 file=121. blocknum=15048. Fractured block found during direct read Data in bad block - type:8. format:2. rdba:0x1e403ac8 last change scn:0x0000.382b9618 seq:0x1 flg:0x08 consistancy value in tail 0x96840801
check value in block header: 0x0, check value not calculated spare1:0x0, spare2:0x0, spare2:0x0

However, when we try to see any problem on the corresponding tablespace, the result is everything normal. The size reported in system view is the same as before. The 'v$recover_file' return no datafile need to be repaired. The 'alter system check datafiles;' return everything are normal.

Do anyone know what's the problem on these messages. Please help and advice. Thank You Very Much!
Thanks in Advance! Received on Sat Jan 13 2001 - 12:42:18 CST