Re: 5.x: how do I get a *swap*-backed /tmp via rc.conf?

From: Sean Winn (sean_at_gothic.net.au)
Date: 10/10/05

  • Next message: Michael L. Squires: "Re: 5.3 -> 5.4 breaks ATA (Intel ICH2)" 
    Date: Tue, 11 Oct 2005 01:09:05 +1000
To: Lowell Gilbert <freebsd-stable-local@be-well.ilk.org>

    Lowell Gilbert wrote:
    > David Wolfskill <david@catwhisker.org> writes:
    >
    >
    >>I made the somewhat unexpected discovery that in FreeeBSD 5-STABLE,
    >>if I use the "tmp*" variables in /etc/rc.conf to have an MFS /tmp
    >>created, it is apparentyly not swap-backed -- as I expected from
    >>the part of the mdmfs man page that reads:
    >>
    >> By default, mdmfs creates a swap-based (MD_SWAP) disk with soft-updates
    >> enabled and mounts it on mount-point.
    >>
    >>and a review of the way mdmfs is invoked by /etc/rc; rather, it appears
    >>to be malloc-backed.
    >>
    >>Here's what's in /etc/{defaults/,}rc.conf about it on one such machine:
    >>
    >>g1-59(5.4-S)[42] grep tmp /etc/{default*/,}rc.conf
    >>/etc/defaults/rc.conf:tmpmfs="AUTO" # Set to YES to always create an mfs /tmp, NO to never
    >>/etc/defaults/rc.conf:tmpsize="20m" # Size of mfs /tmp if created
    >>/etc/defaults/rc.conf:tmpmfs_flags="-S" # Extra mdmfs options for the mfs /tmp
    >>/etc/defaults/rc.conf:isdn_traceflags="-f /var/tmp/isdntrace0" # Flags for isdntrace
    >>/etc/defaults/rc.conf:clear_tmp_enable="NO" # Clear /tmp at startup.
    >>/etc/rc.conf:tmpmfs="YES"
    >>/etc/rc.conf:tmpsize="512m"
    >>/etc/rc.conf:tmpmfs_flags="-i4096"
    >>g1-59(5.4-S)[43]
    >>
    >>And:
    >>
    >>g1-59(5.4-S)[43] sudo mdconfig -l -u md0
    >>md0 malloc 524288 KBytes
    >>g1-59(5.4-S)[44]
    >>
    >>Oh, for some sense of what we're working with:
    >>
    >>g1-59(5.4-S)[44] uname -a
    >>FreeBSD g1-59.catwhisker.org. 5.4-STABLE FreeBSD 5.4-STABLE #6: Sun Oct 9 06:24:17 PDT 2005 root@g1-59.catwhisker.org.:/usr/obj/usr/src/sys/LAPTOP i386
    >>g1-59(5.4-S)[45]
    >>
    >>So, back to my original question: how do I get a *swap*-backed /tmp?
    >>
    >>[The way I was alerted to the possibliity that my /tmp might not
    >>be swap-backed is that I was using a machine running 5-STABLE as a CVS
    >>server, in order to update /usr/ports on another machine. That's why I
    >>have the -i4096 argument in there, BTW: to double the number of inodes
    >>for when the CVS server starts consuming them with wild abandon as it
    >>builds an isomorphic hierarchy to /usr/ports in /tmp. I think it only
    >>took me 3 panics before I poked around in the mailing list archives and
    >>noted scottl's comment about using a swap-backed /tmp instead, which got
    >>me wondering what backing store my /tmp was using. I did look at
    >>/etc/rc.d/tmp, as well a /etc/rc.subr, but I'm still failing to see why
    >>I'm getting a malloc-backed /tmp. FWIW, although the /tmp in question
    >>is an MFS in 4.x, I do this (use the box as a CVS server for /usr/ports)
    >>without problem on 4.x.]
    >
    >
    >
    > It's hard-coded into rc_subr.
    > Changing it to a default parameter and overriding it in rc.conf would
    > probably be easy to get committed.

    Probably really easy, seeing it's already done for RELENG_6 after being
    implemented in CURRENT.

    http://www.freebsd.org/cgi/cvsweb.cgi/src/etc/defaults/rc.conf?rev=1.259&content-type=text/x-cvsweb-markup

    > _______________________________________________
    > freebsd-stable@freebsd.org mailing list
    > http://lists.freebsd.org/mailman/listinfo/freebsd-stable
    > To unsubscribe, send any mail to "freebsd-stable-unsubscribe@freebsd.org"
    >
    _______________________________________________
    freebsd-stable@freebsd.org mailing list
    http://lists.freebsd.org/mailman/listinfo/freebsd-stable
    To unsubscribe, send any mail to "freebsd-stable-unsubscribe@freebsd.org"

  • Next message: Michael L. Squires: "Re: 5.3 -> 5.4 breaks ATA (Intel ICH2)"