On Sat, 28 Sep 2013 01:10:14 +0200, Alan McKinnon wrote about Re: [gentoo-user] separate / and /usr to require initramfs 2013-11-01:
> On 28/09/2013 00:57, Dale wrote: > > Bruce Hill wrote: > >> On Fri, Sep 27, 2013 at 05:33:02PM -0500, Dale wrote: > >>> I'm hoping that since I use eudev, I don't have to worry about > >>> this. If I do, this could get interesting, again. Dale > >> Do you have /usr separate from / ? > > > > Yep. From my understanding tho, eudev is not supposed to be > > affected by this problem tho. > > > > One reason for this being seperate, I have / and /boot on a regular > > partition and everything else on LVM. Sometimes that /usr gets a > > bit full. It's not so bad after I moved all the portage stuff out > > and put it in /var. Now I have to watch /var too. lol > > > Ask yourself this question: > > Why do you have /usr separate? > > No really, *why exactly*? You write as though you expected the question to be regarded as rhetorical. I can't speak for Dale, but since I have much the same arrangement (with /boot and / on physical partitions and everything else under LVM2 control) I shall write from my perspective. The reason I have /usr separate is so that I can have it striped without needing an initramfs. > One of the very first things you do with /usr at boot time is mount > it, and from then on you use it exactly as if it were always on / > anyway. No. The I/O characteristics of a striped /usr are rather different from those of / on a simple partition. > I'll bet that since you moved all of portage out, your mount > options and fs configs are the same between the two anyway. Again no. My portage volume has different mount options from /usr, as it has nosuid and noexec in force. The portage volume is not striped either, as it does not get as much I/O traffic as /usr. > So what > exactly does a separate /usr get you on a stabd-alone workstation buy > you? It buys me decent performance from elderly PATA hard drives. Striping gives a throughput multiplier on that corner of the DASD farm. This is advantageous because /usr/bin and /usr/lib receive a lot of data traffic running application programs -- much more than /bin and /lib. The /usr/bin directory appears earlier in my PATH than /bin and the majority of application software is loaded without /bin being troubled. The faster the /usr LV can respond, the faster software can load. > I've been looking at this for ages and conclude it buys me > nothing but pain. They don't even change much if /home and /var are > elsewhere, so guage your size right (easy to do) and never need look > at it again. > > Separate /usr for the most part is an ancient artifact from decades > ago. It's useful in edge cases but not in the general case with modern > hardware. So why do people do it? I reckon it's inertia and nothign > more. Which is kinda silly as inertia ignores everythign else in the > environment that is changing around you (and *that* is a given). I'm not sure if you're invoking some law of physics here, but inertia does not ignore everything else -- even if it actually offers resistance to change, it does not ignore it. > So unless you have something exotic like /usr mounted off a central > server, or want / on LVM (and your grub doesn't support lvm), you are > going to need an initramfs anyway to get around the circular bootstrap > problem. I am yet to have a circular dependency problem in my bootstrap sequence. Of course, I don't have bluez installed. I also do not have udev or systemd installed. > I say people should make their lives easier and just stick /usr on the > same volume as / and be done with it. It removes a whole lot of > painful scenarios that are going to keep on biting you as the rest of > the world moves on and progresses That then devolves the I/O characteristics of /usr/bin and /usr/lib into those of /bin and /lib, which would make a slow system even slower. -- Regards, Dave [RLU #314465] *-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-* dwn...@ntlworld.com (David W Noon) *-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
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