topic Re: buffer I/O error on device sda in Operating System - Linux

buffer I/O error on device sda

Samer Dahr — Thu, 03 Jan 2008 11:45:35 GMT

Hello,
I have 2 DL380G5 servers on which i have installed redhat linux ES 4. both servers are connected to a MSA 1000 using fiber channel connectors.
i have made all zoning configuration for the san switch.
i have created luns on the msa uning the CLI.
now i am trying to create partitions, volume groups and logical volumes and file systems on the created lun.
on the first server, i noticed that there is /dev/sda and /dev/sdb, and both represent the msa1000 that i have.
but when trying to access the /dev/sda, it always mention that it is uncapable to be read.so i created the patitions using the fdisk utility on the /dev/sdb.
on the second server, i can just see /dev/sda that it is unaccessible too, so i am not able to find the partitions that i have created on the msa via the other server.
on the booting of both servers, i am getting the following:
buffer I/O error on device sda, logical block 1
buffer I/O error on device sda, logical block 2
buffer I/O error on device sda, logical block 3.......

what could the problem be , and why i can't see /dev/sdb on the second server as i the first one?

thanks in advance
Samer

Re: buffer I/O error on device sda

Rob Leadbeater — Thu, 03 Jan 2008 12:56:28 GMT

Hi Samer,

A couple of things to check...

Firstly make sure that the connection type for the hosts on the MSA is set to Linux. That could cause the errors you're seeing.

Secondly, it sounds like you've presented the LUNs to both servers. Are you using any Clustering software ? If not then you'll end up with corrupt file systems.

Hope this helps,

Regards,

Rob

Re: buffer I/O error on device sda

Samer Dahr — Thu, 03 Jan 2008 13:32:10 GMT

Hi Rob,
Thanks for your answer.
first, i will install a cluster software for sure but i would make sure that the lun created is accessible by both servers , and i am till now working on just one server turned on.
could you please tell me how to set the connection type for the hosts on the MSA to Linux ?
thanks and best regards
Samer

Re: buffer I/O error on device sda

Rob Leadbeater — Thu, 03 Jan 2008 13:36:48 GMT

Hi Samer,

You should check the connection profile, with the MSA CLI command:

show connection

If this is listed as Default, then it will be causing problems.

Cheers,
Rob

Re: buffer I/O error on device sda

Samer Dahr — Thu, 03 Jan 2008 13:50:28 GMT

Thanks Rob , I will check this and tell you the result.
but do you think that the firmware version can cause the problem? and if i need to upgrade it , does it make a problem if i do it via a windows server and the servers connected are linux ? i think it does not make sense but just to make sure.

Best Regards
Samer

Re: buffer I/O error on device sda

Rob Leadbeater — Thu, 03 Jan 2008 13:55:57 GMT

The firmware might be a problem, although unlikely... What version is the MSA1000 running ?

Cheers,
Rob

Re: buffer I/O error on device sda

Samer Dahr — Fri, 04 Jan 2008 10:12:51 GMT

the firmware version that i have is 4.98 , i have upgraded it to version 7 (active/active) and now both servers can access the msa and there is no errors on booting.
but what is still faulty is that the first server has 2 paths to the msa (/dev/sda and /dev/sdb) but the second one has just one path (/dev/sda). could this be a hardware problem? i will anyway try to switch the cables and the HBAs and see if it could be the source of the problem