Hi all, hope you are having a nice day, its nice and warm today in Canberra Australia.
iostat -e / -E reports soft and hard errors. Any idea what these are exactly? All I hear are I/O's failing and needing to retry, but no cause as to why they fail.
My SUN guru tells me its our EMC SAN array generating RSCN's or other fibre channle stuff, and the qlogic card then logs back into the fabric, and during that process some I/O has failed. However the iostat errors come up regardless of the EMC san.
I have searched for and read articles, etc, and really found nothing. however one article said the scsi driver doesn't know the disk RPM speed, another saying that SUN array software needs to be turned off.
We have a history with SUNmc causing SAN disk problems by constantly polling the disk for information (which is why we are upgrading it and have turned it off on some servers).
If you have lots of soft errors, are you likely to get a hard error? When you have lots of hard errors (eg, an internal disk is reporting 2400 hard errors with no corresponsing /var/adm/message entries to do with RSCN, scsi, etc) will you end up with track/cylinder errors?
I guess database/application issues will also cause I/O retries just like tcpip.
The number of network output/inpuit/collisions/queues, also do not relate to the iostat -e output.
Many Thanks
take care all