we`ve got a database server machine running a 2.6.18.2 vanilla kernel on Debian Etch. The database is MySQL 5. Everything works fine, but sometimes the server "lags", i.e. it doesn`t respond for 30 seconds. We`ve now investigated the problem and found this messages in syslog (and dmesg):
15:55:44 omega11 kernel: ata1: port is slow to respond, please be patient
15:55:44 omega11 kernel: ata1: soft resetting port
15:55:44 omega11 kernel: ata1: port is slow to respond, please be patient
15:55:44 omega11 kernel: ata1: SATA link up 1.5 Gbps (SStatus 113 SControl 300)
15:55:44 omega11 kernel: ATA: abnormal status 0xD0 on port 0xFFFFC2000000401C
15:55:44 omega11 last message repeated 5 times
15:55:44 omega11 kernel: ata1.00: qc timeout (cmd 0xec)
15:55:44 omega11 kernel: ata1.00: failed to IDENTIFY (I/O error, err_mask=0x4)
15:55:44 omega11 kernel: ata1: failed to recover some devices, retrying in 5 secs
15:55:44 omega11 kernel: ata1: hard resetting port
15:55:44 omega11 kernel: ata1: SATA link up 1.5 Gbps (SStatus 113 SControl 300)
15:55:44 omega11 kernel: ata1.00: configured for UDMA/133
15:55:44 omega11 kernel: ata1: EH complete
15:55:44 omega11 kernel: SCSI device sda: 293046768 512-byte hdwr sectors (150040 MB)
15:55:44 omega11 kernel: sda: Write Protect is off
15:55:44 omega11 kernel: SCSI device sda: drive cache: write back
We`ve got this messages up to 5 times a day since as far as our syslogs reach.
It seems no kind of queuing is used:
# cat /sys/block/sda/device/queue_type
none
# cat /sys/block/sda/device/queue_depth
1
The server is up for 91 days now and has low to medium load (depending on daytime). Since it`s a production server located in a datacenter, we can`t just test some random kernel on it :(
Does somebody have a glue whats going on here? Could it be a hardware failure?
We have an identical machine using the same kernel. It`s used as a webserver. There also this messages shows up, but not that often (10 times in 91 days uptime). If it is a hardware failure, then both machines would been affected by the same hardware problem.
What can we do to fix this problem? Is it known?
I`ve found many posts related to SATA problems, but none seemed to be about this problem.
Do you need additional information?