Phantom unreadable drives, hd0 through hd4, are causing errors

In Grub, in addition to hd5, which is my actual drive, there are hd0 through hd4. Trying to ls them says they have an unknown filesystem. When grub loads, it prints several pages of

error: failure reading sector 0x80 on hd0
error: failure reading sector 0x80 on hd1

etc. It also does this after selecting the OS.

This all started after I added another partition to my (btrfs-formatted) root drive, so maybe it has something to do with that.

What causes this, and how do I fix it?

whoKnows

Posted 2019-04-11T20:50:02.117

Reputation: 111

Are you saying that you don't know the origins of hd0 through hd4? – rickhg12hs – 2019-04-12T22:51:44.060

@rickhg12hs Yes. – whoKnows – 2019-04-13T23:35:58.940

What does fdisk -l /dev/hd show?... Or whatever the device is – rickhg12hs – 2019-04-13T23:39:00.037

1@rickhg12hs I'm not at that computer right now, but Linux doesn't see any additional drives (only grub does) – whoKnows – 2019-04-13T23:54:26.097

Answers

One possible cause of these phantom devices are from your BMC. Various BMCs, which provide IPMI and often a KVM function, will create virtual USB devices when you're using the KVM (also commonly called iKVM.)

While I don't know of a solution for Grub to ignore certain devices, here are a few workarounds:

Manually edit your grub entry at boot to use the correct hdX device for that boot only.
Disconnect iKVM sessions during boot.

I hope somebody comes along with a better answer for this! I've also seen hardware consoles with KVMs (like the Tripp-Lite B070-008-19-IP 8-port rack-mounted console with IP KVM) do this, so suspect anything that connects to the USB bus.

Paul

Posted 2019-04-11T20:50:02.117

Reputation: 281