Hello, A message was already posted here regarding this issue- I experience the same problem with 6 machines, all with Hitachi harddrive, VIA Motherboard which uses the sata_via driver: Once every few days each machine freezes or just stops reading from the HD and throws i/o error messages as pasted below. Note that the first "ata exception Emask" errors apear right after booting, when harddisks plays smoothly. the I/O errors apear only after few hours-days. Is it a known problem? (Already two posts regarding this)? Any solution or at least a way to check it? (I'm using CentOS5 with the latest updates) =============== ata1.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x0 ata1.00: tag 0 cmd 0xb0 Emask 0x1 stat 0x51 err 0x4 (device error) ata1: EH complete ata1.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x0 ata1.00: tag 0 cmd 0xb0 Emask 0x1 stat 0x51 err 0x4 (device error) ata1: EH complete ata1.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x0 ata1.00: tag 0 cmd 0xb0 Emask 0x1 stat 0x51 err 0x4 (device error) ata1: EH complete ata1.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x0 ata1.00: tag 0 cmd 0xb0 Emask 0x1 stat 0x51 err 0x4 (device error) ata1: EH complete ata1.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x0 ata1.00: tag 0 cmd 0xb0 Emask 0x1 stat 0x51 err 0x4 (device error) ata1: EH complete ata1.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x0 ata1.00: tag 0 cmd 0xb0 Emask 0x1 stat 0x51 err 0x4 (device error) ata1: EH complete SCSI device sda: 160834367 512-byte hdwr sectors (82347 MB) sda: Write Protect is off sda: Mode Sense: 00 3a 00 00 SCSI device sda: drive cache: write back nfsd: last server has exited nfsd: unexporting all filesystems NFSD: Using /var/lib/nfs/v4recovery as the NFSv4 state recovery directory NFSD: starting 90-second grace period ata1.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x2 frozen ata1.00: (BMDMA stat 0x24) ata1.00: tag 0 cmd 0xca Emask 0x4 stat 0x40 err 0x0 (timeout) ata1: SATA link up 1.5 Gbps (SStatus 113 SControl 300) ata1: soft resetting port ata1.00: qc timeout (cmd 0xec) ata1.00: failed to IDENTIFY (I/O error, err_mask=0x4) ata1.00: revalidation failed (errno=-5) ata1: failed to recover some devices, retrying in 5 secs ata1: SATA link up 1.5 Gbps (SStatus 113 SControl 300) ata1: soft resetting port ata1.00: qc timeout (cmd 0xec) ata1.00: failed to IDENTIFY (I/O error, err_mask=0x4) ata1.00: revalidation failed (errno=-5) ata1: failed to recover some devices, retrying in 5 secs ata1: SATA link up 1.5 Gbps (SStatus 113 SControl 300) ata1: soft resetting port ata1.00: qc timeout (cmd 0xec) ata1.00: failed to IDENTIFY (I/O error, err_mask=0x4) ata1.00: revalidation failed (errno=-5) ata1.00: disabled ata1: EH complete sd 0:0:0:0: SCSI error: return code = 0x00040000 end_request: I/O error, dev sda, sector 4840645 Buffer I/O error on device sda2, logical block 578975 lost page write due to I/O error on sda2 sd 0:0:0:0: SCSI error: return code = 0x00040000 end_request: I/O error, dev sda, sector 5065613 Buffer I/O error on device sda2, logical block 607096 lost page write due to I/O error on sda2 sd 0:0:0:0: SCSI error: return code = 0x00040000 end_request: I/O error, dev sda, sector 17800565 Buffer I/O error on device sda2, logical block 2198965 lost page write due to I/O error on sda2 sd 0:0:0:0: SCSI error: return code = 0x00040000 end_request: I/O error, dev sda, sector 4835797 Buffer I/O error on device sda2, logical block 578369 lost page write due to I/O error on sda2 sd 0:0:0:0: SCSI error: return code = 0x00040000 end_request: I/O error, dev sda, sector 4840653 Buffer I/O error on device sda2, logical block 578976 lost page write due to I/O error on sda2 Buffer I/O error on device sda2, logical block 578977 lost page write due to I/O error on sda2 Buffer I/O error on device sda2, logical block 578978 lost page write due to I/O error on sda2 Buffer I/O error on device sda2, logical block 578979 lost page write due to I/O error on sda2 Buffer I/O error on device sda2, logical block 578980 lost page write due to I/O error on sda2 Buffer I/O error on device sda2, logical block 578981 lost page write due to I/O error on sda2 sd 0:0:0:0: SCSI error: return code = 0x00040000 end_request: I/O error, dev sda, sector 4841541 ========================= etc, etc.. Thanks - Oren