I installed 11.2 64 bits on a production and a test server. The production server needs about twice the time for writing as the test server. Looking at the system messages, I found the following message appearing about 3 times a day:

Code:
May  3 03:52:14 server kernel: [1345564.810117] ata1.00: qc timeout (cmd 0xa0)
May  3 03:52:14 server kernel: [1345564.810240] ata1.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x6 frozen
May  3 03:52:14 server kernel: [1345564.810264] ata1.00: cmd a0/00:00:00:00:00/00:00:00:00:00/a0 tag 0
May  3 03:52:14 server kernel: [1345564.810266]          cdb 00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00
May  3 03:52:14 server kernel: [1345564.810269]          res 51/20:03:00:00:00/00:00:00:00:00/a0 Emask 0x5 (timeout)
May  3 03:52:14 server kernel: [1345564.810293] ata1.00: status: { DRDY ERR }
May  3 03:52:19 server kernel: [1345569.859035] ata1: link is slow to respond, please be patient (ready=0)
May  3 03:52:24 server kernel: [1345574.857056] ata1: device not ready (errno=-16), forcing hardreset
May  3 03:52:24 server kernel: [1345574.857167] ata1: soft resetting link
May  3 03:52:24 server kernel: [1345575.008259] ata1: clearing spurious IRQ
May  3 03:52:24 server kernel: [1345575.027550] ata1: clearing spurious IRQ
May  3 03:52:24 server kernel: [1345575.046147] ata1: clearing spurious IRQ
May  3 03:52:24 server kernel: [1345575.065243] ata1.00: configured for UDMA/33
May  3 03:52:24 server kernel: [1345575.065895] ata1: EH complete
ata1.00 is the DVD-ROM of the production server:
Code:
<6>[    2.689402] ata1.00: ATAPI: TEAC DVD-ROM DV28EV, D.AE, max UDMA/33
These messages mostly appear when writing to the harddisc, for example when creating a big tgz o making a database backup.

The question is, why do I get a DVD-ROM error when writing to the harddisk?

Can anyone help me with this problem? It's really annoying that the test server is faster than the production server, while the later has the more powerful hardware.