root=/dev/nfs makes arch wait 10 seconds before booting
Task Info (Flyspray) | |
---|---|
Opened By | Antonio (kokoko3k) |
Task ID | 35529 |
Type | Bug Report |
Project | Arch Linux |
Category | Arch Projects |
Version | None |
OS | All |
Opened | 2013-05-29 08:03:22 UTC |
Status | Assigned |
Assignee | Dave Reisner (falconindy) |
Assignee | Giancarlo Razzolini (grazzolini) |
Details
I've a pxe system that mounts "/" over nfs, and i noticed that the 10 seconds the system waits for /dev/nfs always timeout, on every boot. but after that, the system boots fine and the nfs mounts are available. changing rootdelay kernel parameter to a lower value (even just 1 second) , makes the system boots faster and fine;
I went deeper into this, The problem is (seems to be) that the init function: poll_device() in /usr/lib/initcpio/init_functions, waits for the device /dev/nfs (specified in the kernel command line) to be available. But /dev/nfs will never show up because, as stated here: https://www.kernel.org/doc/Documentation/filesystems/nfs/nfsroot.txt
" root=/dev/nfs
This is necessary to enable the pseudo-NFS-device. Note that it's not a
real device but just a synonym to tell the kernel to use NFS instead of
a real device.
"
To make the long story short:
- the kernel needs root=/dev/nfs in order to boot from nfs
- arch init waits for /dev/nfs
- /dev/nfs does not appear because is not meant to be a real device