1) Should I change these SAS disks? The model is not easy to find in my country. --Yes, i would replace the drive in predictive failure.  It may run for awhile, but eventually it will fail and you don't want to risk your data.  2) Should I update the firmware of all SAS disks? --Yes, it is a good idea to update the firmware on the drives.  It helps with their interaction with the controller.  3) Another idea? --Make sure your bios is current as well, at 2.7.0     Regards,
Hello I have a DELL PE 2950 III and I read some errors in the Windows 2012 event logs: The IO operation at logical block address 6bac027 for Disk 2 was retried.The IO operation at logical block address 800 for Disk 3 was retried.The IO operation at logical block address 800 for Disk 4 was retried. These errors appear when I backup the virtual machines (Hyper-V) hosted on this server after I upgrade from Windows 2008 R2 to Windows 2012.  And from several years I have a predictive error for one disk: Predictive Failure reported:  Physical Disk 0:0:3 Controller 0, Connector 0  1) Should I change these SAS disks? The model is not easy to find in my country. 2) Should I update the firmware of all SAS disks? 3) Another idea? The server configuration: - Dell PowerEdge 2950 III.- RAID controller: Perc 6/i (firmware 6.3.1-0003, A14)- RAID 5: 6 x 146 GB ST9146802SS + 2 x 146 GB ST9146803SS.- Disk ST9146802SS: original firmware (2 new versions exists)- Disk ST9146803SS: original firmware (a new version exists)  Thank you
W2012: IO operation was retried