Date: Mon, 26 Apr 2010 19:59:29 -1000 (HST) From: Jeff Roberson <jroberson@jroberson.net> To: Scott Long <scottl@samsco.org> Cc: Alex Keda <admin@lissyara.su>, freebsd-current@freebsd.org Subject: Re: HEADS UP: SUJ Going in to head today Message-ID: <alpine.BSF.2.00.1004261956430.1398@desktop> In-Reply-To: <622DDEDF-0320-49DA-8037-CA8C1F682CC1@samsco.org> References: r2x7d6fde3d1004210606o25fdf542j42cb5fdef75991e2@mail.gmail.com <4BD35437.2060208@lissyara.su> <alpine.BSF.2.00.1004241656270.1398@desktop> <622DDEDF-0320-49DA-8037-CA8C1F682CC1@samsco.org>
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On Sun, 25 Apr 2010, Scott Long wrote: > On Apr 24, 2010, at 8:57 PM, Jeff Roberson wrote: >> On Sun, 25 Apr 2010, Alex Keda wrote: >> >>> try in single user mode: >>> >>> tunefs -j enable / >>> tunefs: Insuffient free space for the journal >>> tunefs: soft updates journaling can not be enabled >>> >>> tunefs -j enable /dev/ad0s2a >>> tunefs: Insuffient free space for the journal >>> tunefs: soft updates journaling can not be enabled >>> tunefs: /dev/ad0s2a: failed to write superblock >> >> There is a bug that prevents enabling journaling on a mounted filesystem. So for now you can't enable it on /. I see that you have a large / volume but in general I would also suggest people not enable suj on / anyway as it's typically not very large. I only run it on my /usr and /home filesystems. >> >> I will send a mail out when I figure out why tunefs can't enable suj on / while it is mounted read-only. >> > > This would preclude enabling journaling on / on an existing system, but I would think that you could enable it on / on a system that is being installed, since (at least in theory) the target / filesystem won't be the actual root of the system, and therefore can be unmounted at will. That's definitely true. Some users have had mixed success enabling it on /. It looks like it is a bug either in g_access or ffs's use of g_access which does not allow tunefs to write after a downgrade. I'm not yet sure how this is presently working for the softdep flag itself, or if it actually is at all. To clarify my earlier statements: Journaling only makes sense when the fsck time is longer than a few tens of seconds. So volumes less than a gig or two don't really need journaling. It just costs extra writes and fsck time will likely be similar. In some pathological cases it can even be faster to fsck a small volume than it is to run the journal recovery on it. Thanks, Jeff > > Scott >
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