[cs615asa] mounting volumes

[Elliot Wasem]

Hey Mark,

Appreciate the help. I took a look at dmesg before and after mounting, and found that before I mounted the volume, the output looked like this:
and after I mounted the volume using the command:
$ aws ec2 attach-volume --instance-id i-<id> --volume-id vol-<id> --device /dev/sdh
it looked like this:

which indicated to me that the device is called xbd2 . I don't see it under /dev, but I'm able to read and write to it. I do however see a bunch of devices ranging from xbd2a to xbd2p . I'm able to dd directly to /dev/xbd2 , and read from it with dd as well. So, I guess that's my attached volume.

Does anyone know why there are 21 devices starting with xbd2, but no device simply called xbd2? Is it because there are 21 sectors on the device, and it's addressing each sector separately?
Thanks,
Elliot Wasem
https://elliotwasem.xyz

On Feb 16 2020, at 12:56 pm, Mark Freeman <mfreema1 at stevens.edu> wrote:
>
> Hi Elliot,
>
> I believe there is a block device mapping that occurs, which differs based on AMI. So even if you specify to mount at /dev/sda3, that gets mapped to somewhere else.
>
> Have you checked on the instance using dmesg? That usually gives a notification of where it mapped into.
>
> If that doesn't work, perhaps try specifying a different --device mount point when attaching the volume. Say /dev/sdh or something like that?
>
> Not sure if this helps your situation, but figured I'd chime in.
>
> Thanks!
> Mark
>
>
> On Sun, Feb 16, 2020, 12:48 PM Elliot Wasem <ewasem at stevens.edu (mailto:ewasem at stevens.edu)> wrote:
> > Hey all,
> >
> > I feel like I'm losing my mind here, but I can't find a volume once it's mounted.
> > I've started a netbsd instance, created a volume, and mount it to /dev/sda3. It successfully mounts, and all flags indicate it's attached (both describe-volume from cli interface, as well as the GUI on aws console). However, I can't find the stinking device when I look inside /dev. Anyone know what it should be called?
> > Best,
> > Elliot Wasem
> > https://elliotwasem.xyz (https://nam02.safelinks.protection.outlook.com/?url=https%3A%2F%2Felliotwasem.xyz%2F&data=02%7C01%7Cewasem%40stevens.edu%7Ce61c07ca334741667cdf08d7b3098a59%7C8d1a69ec03b54345ae21dad112f5fb4f%7C0%7C0%7C637174725872373841&sdata=ey0uX7kD1RAnx0xT3%2FF%2F91ueq0QxSHF6NATVVtJnd0k%3D&reserved=0)
> >
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