PowerPath RHEL4 dmesg buffer I/O error on sd* device

Question

Hi, I've recently installed PP 4.5.1 on RHEL4 kernel version 2.6.9-42.0.10.ELsmp and wanted to confirm whether the following errors reported by dmesg are expected or not. The errors displayed take the form: Buffer I/O error on device sdi, logical block 0 end_request: I/O error, dev sdi, sector 512 Buffer I/O error on device sdi, logical block 64 Buffer I/O error on device sdi, logical block 65 Buffer I/O error on device sdi, logical block 66 Buffer I/O error on device sdi, logical block 67 Buffer I/O error on device sdi, logical block 68 Buffer I/O error on device sdi, logical block 69 Buffer I/O error on device sdi, logical block 70 Buffer I/O error on device sdi, logical block 71 end_request: I/O error, dev sdi, sector 512 Buffer I/O error on device sdi, logical block 64 The errors relate to a number of different sd devices.....sdi, sdj, sdr, sdq, etc., but powermt display dev=all doesn't report doesn't display these devices under the I/O paths. I can see the /dev/emcpower devices and have partitioned them, laid out a filesystem, mounted them and can write data so they seem to be OK. The only thing I can think is that the sd devices displaying errors are only being reserved by an SP and not presented to the OS and if an I/O path failover were to occur the LUNs on that SP would become active. Is that correct to assume? Thanks, Simon

admin111111 · Answer

Pls see Primus emc157139In summary: The devices logging the I/O error are assigned to SP-B, but currently 'owned' by SP-A. The CLARiiON array is an active-passive array so this is normal behavior when multiple paths are utilized. These messages logged at boot up may be ignored.

SGibbs · Answer

Thanks....that makes sense now.

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