Arch Linux

drake.withers

Member

Registered: 2015-10-11

Posts: 5

External Hard Drives Not Recognized

Hello all,

I'm fairly adept at using Arch, but I lack a solid understanding of the fundamentals, so I apologize if this question is elementary to most of you. I've searched different forums and found some relevant articles but I'm still missing something and I'd like help to understand what's going on.

After a fresh install on a new-to-me laptop, when I plug in any of my two external HDDs, nothing happens. After a brief period, a message appears in the console:

"[  521.658050] sd 0:0:0:0: [sda] Asking for cache data failed"

I've never experienced this problem with previous Arch builds. All the other articles I've read talk about the usb-storage kernel module and/or blacklisting uas.

I'd appreciate if someone knowledgeable were willing to take the time to explain this to me from zero, or at least tell me what I'm missing to properly understand this frustrating issue.

Thanks in advance!

Drake

ewaller

Administrator

From: Pasadena, CA

Registered: 2009-07-13

Posts: 20,659

Re: External Hard Drives Not Recognized

Thumb drive, spinning drive, or SSD?

How do you identify that they are not recognized?  What is the output of lsblk before and after you attach the drive?

---

Nothing is too wonderful to be true, if it be consistent with the laws of nature -- Michael Faraday
The shortest way to ruin a country is to give power to demagogues.— Dionysius of Halicarnassus
---
How to Ask Questions the Smart Way

drake.withers

Member

Registered: 2015-10-11

Posts: 5

Re: External Hard Drives Not Recognized

I noticed the problem while attempting to mount my external HDD, spinning-type. Worked fine on a live version of Arch and on Windows.

Strangely, it seems to be working fine this morning. Last night I ran mkinitcpio -P with "usb-storage" passed explicitly in the modules section of /etc/mkinitcpio.conf. It did not seem to resolve the issue, but this morning in attempting to replicate it for you the device is recognized just fine.

While I can't replicate the lsblk output to share with you, I can tell you what was happening. The device was showing up as an entry in lsblk as simply "sda" without its single partition being printed in the tree. After a few seconds of waiting, the message "[  521.658050] sd 0:0:0:0: [sda] Asking for cache data failed" would appear. The size printed in the output of lsblk read something small like 15M, though it is a 3.6TB removable hard drive.

Today's output:

NAME        MAJ:MIN RM   SIZE RO TYPE MOUNTPOINTS
sda           8:0    0   3.6T  0 disk
└─sda1        8:1    0   3.6T  0 part
nvme0n1     259:0    0 238.5G  0 disk
├─nvme0n1p1 259:1    0   512M  0 part /boot
├─nvme0n1p2 259:2    0    10G  0 part [SWAP]
└─nvme0n1p3 259:3    0   228G  0 part /

Any idea what's going on here? I'm skeptical about my "fix" as usb-storage should be included in the initial ramdisk by default, right? Though it seems to be working fine now I'd really like to understand what's happening.

Last edited by drake.withers (2022-08-31 13:40:25)

Slithery

Administrator

From: Norfolk, UK

Registered: 2013-12-01

Posts: 5,776

Re: External Hard Drives Not Recognized

Did you maybe update the kernel and then not reboot before connecting the drives?

---

No, it didn't "fix" anything. It just shifted the brokeness one space to the right. - jasonwryan
Closing -- for deletion; Banning -- for muppetry. - jasonwryan

aur - dotfiles

drake.withers

Member

Registered: 2015-10-11

Posts: 5

Re: External Hard Drives Not Recognized

That's very possible. It was late, and I was tired.

Is "usb-storage" a module that typically needs to be loaded explicitly? I don't remember having to do this before. Are there any other kernel modules I may be neglecting to load?

ewaller

Administrator

From: Pasadena, CA

Registered: 2009-07-13

Posts: 20,659

Re: External Hard Drives Not Recognized

Is "usb-storage" a module that typically needs to be loaded explicitly?

No, it should load dynamically when needed.  Which lends credence to having had a mismatched kernel.
When a kernel is updated, the old kernel modules are removed from /lib/modules, and a new directory is created for the new kernel's mosules.
The old kernel continues to run -- generally until the system is rebooted. If, after the modules have been updated, the running kernel tries to load a module (perhaps because someone attached a usb storage device), that process will fail because the modules for the running kernel are gone.  Rebooting, the new kernel is used, and it can find its modules and things are right with the world again.

---

Nothing is too wonderful to be true, if it be consistent with the laws of nature -- Michael Faraday
The shortest way to ruin a country is to give power to demagogues.— Dionysius of Halicarnassus
---
How to Ask Questions the Smart Way

drake.withers

Member

Registered: 2015-10-11

Posts: 5

Re: External Hard Drives Not Recognized

Thanks for your help! I like your explanation. It also appears that I'm having I/O problems with this particular HDD.

Best,
Drake