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#1 2016-03-18 18:48:41
- dumbl3d0re
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[SOLVED] Practical difference between kernel parameters "rw" and "ro"?
What practical difference does it make to use the kernel parameter "rw" instead of "ro"? Why is "ro" default if "everyone" (all examples in the wiki) should use "rw"?
Last edited by dumbl3d0re (2016-03-19 10:01:28)
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#2 2016-03-18 20:02:49
- Roberth
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Re: [SOLVED] Practical difference between kernel parameters "rw" and "ro"?
Rw is what is default. Rw means that a partition is readable and writable, while Ro means that they are only readable.
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#3 2016-03-18 20:08:42
- ugjka
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Re: [SOLVED] Practical difference between kernel parameters "rw" and "ro"?
Read-only is a fallback when nothing is specified. Consider it a safety feature.
Last edited by ugjka (2016-03-18 20:10:24)
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#4 2016-03-18 20:12:53
- dumbl3d0re
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Re: [SOLVED] Practical difference between kernel parameters "rw" and "ro"?
Rw is what is default.
mkinitcpio uses ro as default value when neither rw or ro is set by the boot loader. [1]
I can't find any information on the systemd-boot page that says that it use "rw" by default. If you are right and the wiki wrong, I would appreciate it if you could edit the wiki. 
Rw means that a partition is readable and writable, while Ro means that they are only readable.
Read-only is a fallback when nothing is specified. Consider it a safety feature.
I understand that I should use "rw", but I don't understand why?
[1] https://wiki.archlinux.org/index.php/Ke … meter_list
Last edited by dumbl3d0re (2016-03-18 20:17:05)
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#5 2016-03-18 20:38:56
- WorMzy
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Re: [SOLVED] Practical difference between kernel parameters "rw" and "ro"?
Read the footnote.
The kernel defaults to rw (see 'man bootparam'), but the initrd scripts default to ro and overrides this. The bootloader you use is irrelevant.
You should specify the rw flag if you're using the fsck flag in your mkinitcpio config, the reason for that is described here.
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#6 2016-03-18 20:43:46
- brebs
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Re: [SOLVED] Practical difference between kernel parameters "rw" and "ro"?
I think the point is that a *read-only* filesystem can be fsck'd and repaired, and also stands more chance of being mountable (which is pretty essential for bootup). Automatically FSCKing the root filesystem at bootup (and triggering a repair, if needed) is a sensible precaution.
As a nice example of how it's done (cough), see my initscript, which is a cobbling together of all the nice parts I saw and pinched from other initscripts. Except systemd of course.
Last edited by brebs (2016-03-18 20:44:18)
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