when we run the following dmesg on rhel 7.2 , we get errors about assuming drive cache

dmesg --level=err
[    5.325381] sd 0:0:0:0: [sda] Assuming drive cache: write through
[    5.325492] sd 0:0:5:0: [sde] Assuming drive cache: write through
[    5.325637] sd 0:0:3:0: [sdc] Assuming drive cache: write through
[    5.325667] sd 0:0:4:0: [sdd] Assuming drive cache: write through
[    5.326309] sd 0:0:2:0: [sdb] Assuming drive cache: write through
[   10.277944] piix4_smbus 0000:00:07.3: SMBus Host Controller not enabled!

any idea what is the meaning of this kernel error?

I have read the redhat post - https://access.redhat.com/solutions/42752

but not clearly what is the solution ?

Note - I must to said that servers are after unexpected reboot


1 Answer 1


From the link you gave, “So these events can typically be ignored.” That’s the solution.

The kernel prints the message to err on the side of caution; all it means is that the kernel tried to determine the drives’ caches’ characteristics, using an optional feature of the SCSI specification, but the drives don’t support it so the characteristics couldn’t be obtained. There’s nothing to do about it.

(The only drives I’m aware of that provide the required information are SCSI or SAS drives.)

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .