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On Sat, 15 Dec 2012 10:16:05 +0200 |
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nunojsilva@×××××××.pt (Nuno J. Silva) wrote: |
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> On 2012-12-14, Mark Knecht wrote: |
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> |
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> > I guess the other question that's lurking here for me is why do you |
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> > have /usr on a separate partition? What's the usage model that |
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> > drives a person to do that? The most I've ever done is |
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> > move /usr/portage and /usr/src to other places. My /usr never has |
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> > all that much in it beyond those two directories, along with |
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> > maybe /usr/share. Would it not be easier for you in the long run to |
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> > move /usr back to / and not have to deal with this question at all? |
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> |
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> I may be wrong in this one, but the idea I have is that your regular |
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> applications (so, most of them) all lie under /usr/ -- /lib /bin and |
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> others are for essential system tools. |
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> |
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That was the original reason for having / and /usr separate, and it |
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dates back to the early 70s. The other reason that stems from that time |
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period is the size of disks we had back then - they were tiny and often |
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a minimal / was all that could really fit on the primary system drive. |
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Gradually over time this setup became the norm and people started to |
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depend on it, and more importantly, started to believe it was important |
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to retain it. It's their right to believe that. |
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Recently I decided to measure if I still needed a separate /usr (I was |
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a long time advocate of retaining it). I'm in the lucky position of |
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having ~200 Linux machines, all distinctly different, at my disposal, |
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so I trawled through memory and incident logs looking for cases where a |
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separate /usr was crucial to recovery after any form of error. To my |
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surprise, I found none at all and those logs go back 5 years. |
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So I got to change my mind (not something I do very often I admit) and |
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concluded that separate base and user systems (/ and /usr) was no |
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longer something I needed to do - the "system" - disks, hardware and |
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the software on the disks - was very reliable, and what I really needed |
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was ability to boot from USB rescue disks. I did find, not |
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unsurprisingly, that I also really needed /usr/local on a separate |
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partition but that's because of how we install our in-house software |
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here, plus our backup policies. |
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It also goes without saying that these days we |
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need /home, /var, /var/log and /tmp to all be on their own filesystem, |
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and we need that more than ever. |
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I thought I should just toss that in the ring for people who are |
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undecided where they stand on the debate of separate / vs /usr. It's |
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what I found on our production, dev and staging servers, plus a whole |
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lot of people's personal workstations (sysadmins and devs). The |
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environment is a large corporate ISP that defies categorization, we |
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almost have at least one of every imaginable use-case for running on |
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Linux except something in the Top 100 SuperComputer list. I reckon it's |
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about as representative as I'm ever gonna see. |
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People are free to draw their own conclusions as always, and real data |
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is valuable in arriving at those conclusions. YMMV. |
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-- |
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Alan McKinnon |
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alan.mckinnon@×××××.com |
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