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I was reading my logwatch this morning and I've noticed that there are a lot of kernel errors. I'm on CentOS 6 and the machine acts as a web server. Can anyone help me understand what these mean and if I need to take any action?

Fixing these sort of errors is not normally part of my job and as such I have virtually no experience with things like this. I'm particularly worried that the read and write errors may be indicating a disk has failed? Any help is very appreciated!

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Something is wrong in the I/O subsystem, disk or controller probably.. – NickW Apr 29 '13 at 8:25
@NickW Sorry, bit of a noob here, what's a controller? – GhostInTheSecureShell Apr 29 '13 at 8:26
Well, you know the disk is connected with a cable to the motherboard, on the motherboard there is usually some dedicated circuitry allowing other parts of the computer to talk to the disks. You probably need to do a proper check of your disks. – NickW Apr 29 '13 at 9:25
Brilliant, thanks for your explanation and help. – GhostInTheSecureShell Apr 29 '13 at 9:32
up vote 1 down vote accepted

Most likely you have either a bad disk, or a bad SCSI controller (which is what the disks connect to). If this is happening on a hardware RAID array, the RAID controller might be bad.

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Great, thanks. Yes the server has RAID so that would make sense. So these problems need fixing and shouldn't be left as is? What I'm asking is: do I need to take any action? – GhostInTheSecureShell Apr 29 '13 at 9:17
Absolutely. If there isn't already filesystem corruption, there will be if you leave it like that. This type of error often happens when the RAID controller (or drives) stop responding to commands. – Falcon Momot Apr 29 '13 at 9:25
Brilliant, thanks for your explanation and help. – GhostInTheSecureShell Apr 29 '13 at 9:32
Nailed it. The RAID controller was bad. Thank you. – GhostInTheSecureShell May 1 '13 at 8:57
Woot. Np. At least you get to keep the drives :) – Falcon Momot May 2 '13 at 1:13

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