I started getting the following errors every night when the /var partition backed up on one of my CentOS 5 servers.

DUMP: read error from /dev/sda5: Input/output error: [block 4125240, ext2blk 0]: count=515655
DUMP: read error from /dev/sda5: Input/output error: [block 4125252, ext2blk 0]: count=515656
DUMP: read error from /dev/sda5: Input/output error: [sector 4125240, ext2blk 0]: count=515655
DUMP: read error from /dev/sda5: Input/output error: [sector 4125252, ext2blk 0]: count=515656
DUMP: read error from /dev/sda5: Input/output error: [sector 4125241, ext2blk 0]: count=515655
DUMP: read error from /dev/sda5: Input/output error: [sector 4125253, ext2blk 0]: count=515656
DUMP: read error from /dev/sda5: Input/output error: [sector 4125242, ext2blk 0]: count=515655
DUMP: read error from /dev/sda5: Input/output error: [sector 4125254, ext2blk 0]: count=515656
DUMP: read error from /dev/sda5: Input/output error: [sector 4125243, ext2blk 0]: count=515655
DUMP: read error from /dev/sda5: Input/output error: [sector 4125255, ext2blk 0]: count=515656
DUMP: read error from /dev/sda5: Input/output error: [sector 4125244, ext2blk 0]: count=515655
DUMP: read error from /dev/sda5: Input/output error: [sector 4125245, ext2blk 0]: count=515655
DUMP: read error from /dev/sda5: Input/output error: [sector 4125246, ext2blk 0]: count=515655
DUMP: read error from /dev/sda5: Input/output error: [sector 4125247, ext2blk 0]: count=515655

Also, I found the following kinds of message in the messages file:

May 7 02:34:37 white1 kernel: ata1.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x0
May 7 02:34:37 white1 kernel: ata1.00: BMDMA stat 0x24
May 7 02:34:37 white1 kernel: ata1.00: cmd c8/00:50:ea:9f:03/00:00:00:00:00/e3 tag 0 dma 40960 in
May 7 02:34:37 white1 kernel: res 51/40:00:08:a0:03/00:00:00:00:00/03 Emask 0x9 (media error)
May 7 02:34:37 white1 kernel: ata1.00: status: { DRDY ERR }
May 7 02:34:37 white1 kernel: ata1.00: error: { UNC }
May 7 02:34:37 white1 kernel: ata1.00: configured for UDMA/133
May 7 02:34:37 white1 kernel: ata1: EH complete
May 7 02:34:40 white1 kernel: ata1.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x0
May 7 02:34:40 white1 kernel: ata1.00: BMDMA stat 0x24
May 7 02:34:40 white1 kernel: ata1.00: cmd c8/00:50:ea:9f:03/00:00:00:00:00/e3 tag 0 dma 40960 in
May 7 02:34:40 white1 kernel: res 51/40:00:08:a0:03/00:00:00:00:00/03 Emask 0x9 (media error)
May 7 02:34:40 white1 kernel: ata1.00: status: { DRDY ERR }

From single user mode with /var dismounted, I ran the following:

# e2fsck -c /dev/sda5

I wish I had kept the output, but I know I accepted the defaults ( “Y” ) for all the prompts or which their were a couple. After it completed, I ran dump that completed without error. We will see how it goes from here. According to the man page, any bad blocks found using this command are added to the bad block inode so that they are used by any files or directories.