These records arise repeatly in /var/log/messages, I think there must be a bad sector on the hard disk, does it?

Mar 27 15:46:48 MailServer kernel: ata2: status=0x51 { DriveReady SeekComplete Error }
Mar 27 15:46:48 MailServer kernel: ata2: error=0x40 { UncorrectableError }
Mar 27 15:46:48 MailServer kernel: ata2: status=0x51 { DriveReady SeekComplete Error }
Mar 27 15:46:48 MailServer kernel: ata2: error=0x40 { UncorrectableError }
Mar 27 15:46:48 MailServer kernel: ata2: status=0x51 { DriveReady SeekComplete Error }
Mar 27 15:46:48 MailServer kernel: ata2: error=0x40 { UncorrectableError }
Mar 27 15:46:48 MailServer kernel: ata2: status=0x51 { DriveReady SeekComplete Error }
Mar 27 15:46:48 MailServer kernel: ata2: error=0x40 { UncorrectableError }
Mar 27 15:46:48 MailServer kernel: ata2: status=0x51 { DriveReady SeekComplete Error }
Mar 27 15:46:48 MailServer kernel: ata2: error=0x40 { UncorrectableError }
Mar 27 15:46:48 MailServer kernel: scsi1: ERROR on channel 0, id 1, lun 0, CDB: Read (10) 00 00 04 7b a5 00 00 08 00
Mar 27 15:46:48 MailServer kernel: Current sda: sense key Medium Error
Mar 27 15:46:48 MailServer kernel: Additional sense: Unrecovered read error - auto reallocate failed
Mar 27 15:46:48 MailServer kernel: end_request: I/O error, dev sda, sector 293797
Mar 27 15:46:48 MailServer kernel: ata2: status=0x51 { DriveReady SeekComplete Error }
Mar 27 15:46:48 MailServer kernel: ata2: error=0x40 { UncorrectableError }
Mar 27 15:46:48 MailServer kernel: scsi1: ERROR on channel 0, id 1, lun 0, CDB: Read (10) 00 00 04 7b a6 00 00 07 00
Mar 27 15:46:48 MailServer kernel: Current sda: sense key Medium Error
Mar 27 15:46:48 MailServer kernel: Additional sense: Unrecovered read error - auto reallocate failed
Mar 27 15:46:48 MailServer kernel: end_request: I/O error, dev sda, sector 293798

Thanks.

Yes, should be replaced.

Thank you.

And there is another system, which build on RAID5. One of its partition always has problem every time I transport large amount of datas:

Mar 27 09:14:24 four-cpus kernel: EXT3-fs error (device sdb1): ext3_new_block: Allocating block in system zone - block = 418611201
Mar 27 09:14:24 four-cpus kernel: Aborting journal on device sdb1.
Mar 27 09:14:24 four-cpus kernel: EXT3-fs error (device sdb1) in ext3_prepare_write: Journal has aborted
Mar 27 09:14:24 four-cpus kernel: __journal_remove_journal_head: freeing b_committed_data
Mar 27 09:14:24 four-cpus kernel: ext3_abort called.
Mar 27 09:14:24 four-cpus kernel: EXT3-fs error (device sdb1): ext3_journal_start_sb: Detected aborted journal
Mar 27 09:14:24 four-cpus kernel: Remounting filesystem read-only
Mar 27 14:46:47 four-cpus kernel: ext3_abort called.
Mar 27 14:46:47 four-cpus kernel: EXT3-fs error (device sdb1): ext3_remount: Abort forced by user
Mar 27 14:46:47 four-cpus kernel: ext3_abort called.
Mar 27 14:46:47 four-cpus kernel: EXT3-fs error (device sdb1): ext3_remount: Abort forced by user

Then, sdb1 became read-only filesystem.