Re: Sysinstall automatic filesystem size generation.

From: Matthias Buelow (mkb_at_incubus.de)
Date: 08/29/05

  • Next message: Chuck Swiger: "Re: Sysinstall automatic filesystem size generation." 
    Date: Mon, 29 Aug 2005 23:56:13 +0200
To: Chuck Swiger <cswiger@mac.com>

    Chuck Swiger wrote:

    >Yet you seem willing to spend time discussing the matter...?

    Because it's somewhat of my pet peeve and I always see the mantra-like
    repetition of the argument that "you have to disable the write-back
    cache if you want any safety at all", which is a) extremely
    disadvantageous with today's IDE/SATA drives and hardly feasible
    in reality, and b) other systems like Windows and Linux can operate
    much safer with the cache _enabled_, on most drives except the most
    pathetic ones which are totally broken.

    >>One often sees the "softupdates" argument being fielded by FreeBSD
    >>advocates, typically against Linux users with journalled fs, on web
    >>forums, usenet and other less authoritative (and knowledgable)
    >>places of discussion, and it is often presented as if it were some
    >>kind of magic bullet that makes filesystem corruption impossible.
    >
    >"Often?" Strawman test: can you point out 3 examples by message-id or URL?

    A Google search finds them quickly:

    http://www.heise.de/ix/foren/go.shtml?read=1&msg_id=7335045&forum_id=70615
    (german, argument is that "softupdates is at least a match for a
    journalled fs"),

    http://lists.freebsd.org/pipermail/freebsd-questions/2003-June/009967.html
    ("FS + SoftUpdates is much better than journaling!")

    http://aussatz.antville.org/topics/HowTos/
    (german, argument is "1. practically nothing can break when power
    goes out", and even that you can switch off the machine without any
    problems, except for losing the files that have been written to in
    the last seconds. Of course no mentioning of disk cache or any
    sophistication whatever.)

    >And if you prefer to run a journalled filesystem under Linux instead of
    >softupdates under FreeBSD, by all means, do whatever makes you happy.

    I don't want to do that (that is, I do want that, of course, if I'm
    using Linux, but in general I don't care about Linux). The point
    is, that both Windows and recent Linux make great effort to ensure
    filesystem correctness by using request barriers and clever flushing,
    or even complete disabling/reenabling of the cache at these barrier
    points, even on consumer-grade hardware. While with FreeBSD, the
    attitude generally seems to be a snobby "here's a dime, kid, go buy
    yourself a real computer". That might work for server hardware but
    for the typical PC, which is a commodity product, and where one
    often cannot even select the hardware (be it because your employer
    puts the machine in your office, or you just order some machine
    somewhere because tinkering with components until a PC works
    flawlessly has become a royal PITA and waste of time) and so the
    operating system generally has to work with "normal" off-the-shelf
    hardware, which means, cheap IDE/SATA stuff, and not a super-expensive
    battery-backed U320 SCSI-RAID with a gratis golden Rolex and 1-year
    free membership in the Dubai Nad al-Sheba golf club.

    >PS: I don't want a thread to end on a negative note. It would be useful if
    >FreeBSD had a more adaptable method for dealing with drive power management
    >and caching; in particular, for laptops it might be nice to cache data for
    >much longer-- perhaps even hours-- if nothing fsync()s, in order to permit
    >the drive to spin down.

    My notebook lies to me everytime when the battery is going to be
    out of juice soon (one of the reason I experience powerouts frequently,
    when I don't pay attention), so that seems to be somewhat unreliable
    to me..

    mkb.
    _______________________________________________
    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: Chuck Swiger: "Re: Sysinstall automatic filesystem size generation."

    Relevant Pages

    • Re: Are Linux users all childish fools? What better reason to use Windows.
      ... As a Linux user here, ... denser drives with 8MB cache should really ... Windows does not support the 6410 chipset. ... Microsoft does not support hardware. ...
      (alt.os.linux.suse)
    • Re: Memory used - but where?
      ... Linux tries to make the best use of the available memory as it is ... disk drives and hard drives. ... A typical 7200 RPM drive with an 8 Mb internal cache can deliver about ...
      (comp.os.linux.misc)
    • Re: evangelizing linux not needed
      ... >> things I like about Linux. ... but he had given me some SCSI drives, one of which was a Quantum ... >Linux (as long as the hardware was Linux compatible). ...
      (alt.os.linux)
    • Re: Linux compatible hardware
      ... >> I'm looking at a Dell 4700. ... So here are some hardware questions. ... >> both to work as CD drives and the second to write under Linux. ...
      (comp.os.linux.misc)
    • Re: Linux compatible hardware
      ... >> I'm looking at a Dell 4700. ... So here are some hardware questions. ... >> both to work as CD drives and the second to write under Linux. ...
      (comp.os.linux.hardware)
    • Quantcast