Are these SATA errors dangerous?
While I essentially agree with Geppettvs D'Constanzo's answer, I would suggest that some of the first things you might also try are
Checking that your SATA cable is securely attached and plugged into the sockets on the motherboard and hard drive.
Replacing your SATA cable. SATA cables are (relatively) inexpensive and you do sometimes get a "bad" one. Often simply replacing the cable is the easiest way to diagnose and solve a problem like this.
(Although it is somewhat unexpected that two cables would both be bad at the same time. Still, it's an easy thing to check so in my opinion probably worth doing.)
I just saw you pastbins containing the SMART data for your drives. Notice the unexpectedly large number of CRC errors for drives sdb and sdc. I suggest you start by checking the cables and connections for those drives.
junior@mediacenter:/$ sudo smartctl -a /dev/sda
...
Model Family: SAMSUNG SpinPoint M7E (AFT)
Device Model: SAMSUNG HM321HI
...
199 UDMA_CRC_Error_Count 0x0036 200 200 000 Old_age Always - 0
junior@mediacenter:/$ sudo smartctl -a /dev/sdb
...
Model Family: SAMSUNG SpinPoint F4 EG (AFT)
Device Model: SAMSUNG HD204UI
...
199 UDMA_CRC_Error_Count 0x0036 100 100 000 Old_age Always - 57
junior@mediacenter:/$ sudo smartctl -a /dev/sdc
...
Model Family: SAMSUNG SpinPoint F4 EG (AFT)
Device Model: SAMSUNG HD204UI
...
199 UDMA_CRC_Error_Count 0x0036 100 100 000 Old_age Always - 398
OK. So not a latpop then. ;-)
Of course, if this is happening on a laptop than none of the above apply and I'm not sure what advice to offer. Maybe remove and re-install the hard drive? Perhaps it just needs to be re-seated in its socket to improve the connection?
sbd and sdc are connected on the same external e-sata cable (Thermaltake Duo HDD Dock). i'll replace my e-sata cable.
It could be due to a faulty or low quality cable. It could also be that the cable is somehow moved, bumped, or otherwise jostled while the drive is being used.
It looks like you have a bad quality/damaged SATA Power/Data Cable. Which may be causing Bad CRC's. They aren't harmful at all and you can live with them but you are going to lose a lot of data soon.
The SMART report of your hard disk drives looks sane, so I am for power supply issues based on my experience when setting 5 hard disk drives in the same case/power source. I finished using an external power source (475W) for 2 drives and the case's 600W for all the case including GPU, optical and hard disk drives.
Anyway, I suggest you to run a full backup before you do anything else. If possible, clone your hard disk drive, after which you should check your cables and power source voltages.
There seems to be a problem between some kernel versions ans some SATA controllers.
I have recently started to suffer a very similar problem (not sure if it is just the same) on a web server running Scientific Linux.
The most accurate and complete information I have found about such problem is this launchpad bug.
In short: Disabling NCQ seems to be the best workaround for users having this problem.