Date: Wed, 21 Apr 2010 19:16:08 +1000 From: David N <davidn04@gmail.com> To: Andrew Reilly <areilly@bigpond.net.au> Cc: freebsd-fs@freebsd.org Subject: Re: gjournal: what is it good for? Message-ID: <g2u4d7dd86f1004210216wa8dc9ed1i44776068add4c530@mail.gmail.com> In-Reply-To: <20100421085228.GA27892@duncan.reilly.home> References: <20100418235428.GC4620@duncan.reilly.home> <20100420234447.GB1737@garage.freebsd.pl> <20100421011834.GA24928@duncan.reilly.home> <k2q4d7dd86f1004201920s2139647aja783e86e266153ca@mail.gmail.com> <20100421024803.GA25701@duncan.reilly.home> <r2q4d7dd86f1004210105o1ab574b7g350822e9bed99b82@mail.gmail.com> <20100421085228.GA27892@duncan.reilly.home>
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On 21 April 2010 18:52, Andrew Reilly <areilly@bigpond.net.au> wrote: > On Wed, Apr 21, 2010 at 06:05:02PM +1000, David N wrote: >> On 21 April 2010 12:48, Andrew Reilly <areilly@bigpond.net.au> wrote: >> > On Wed, Apr 21, 2010 at 12:20:46PM +1000, David N wrote: >> >> What kind of disks are you using? Or what hardware are you using? >> > >> > Several: main /usr is on a gjournal on top of a gmirror over a >> > pair of Samsung 1TB 3.5" SATA drives, but I have other gjournals >> > on a 750G WD SATA, a 1.5T Seagate and another 1TB WD MyBook >> > firewire unit. =A0There is brokenness in the firewire connection >> > that results in me always coming up manually through single-user >> > mode, at the moment. =A0In single user mode pilot error is >> > sufficient to account for the problems that I was having with >> > mount vs fsck of the gjournalled drives, I'm fairly sure. > >> Wow, thats a setup. > > More an artifact of fair old age and accretion than design... > >> I have a few more questions. >> >> Your first email, you mentioned gjournal overflow panics. Have you fixed= that? > > No: I've avoided it, at risk of incomplete backups, by leaving > the -L (snapshot) option off my backup "dump" calls. =A0I'm fairly > certain that I can generate those panics on demand, now that I > know what's causing them. =A0(I prefer not to, of course, this > machine is in constant use.) > >> I see you are gmirroring the slices, when you did the gmirror + >> gjournal slice, did you check the bsdlabel? sometimes it doesn't >> report the right block size, and the disk + journal overlap. I had >> this happen to me on my first setup which resulted in the overflow >> panics. > > Not sure about that. =A0All of my disks only have one bsdlabel, on > the raw provider. =A0I fdisk -BI; bsdlabel -w -B and then newfs > the ...s1a partition, as a general rule. =A0Now that I'm running > gjournal, that's fdisk; bsdlabel; gjournal label ...; newfs > ...s1a.journal. =A0There isn't a label between the gjournal and > the file system. > > In the case of my main, gmirrored disk pair, I bsdlabel -e'd > after the "use whole disk" standard procedure and made liberal > use of "*" wildcards to make sure that bsdlabel did the right > thing. =A0I was *very* glad when I didn't have to muck about > calculating sector offsets any more. > > I have my mirror'd pair layered: fdisk; bsdlabel; gmirror on > ad[46]s1a, ad[46]s1d and ad[46]s1e, separately, rather than > mirroring the raw ad4/ad6 pair and then bsdlabeling the > resulting mirror because I couldn't see the point in swapping to > a mirror. =A0So I swap to ad4s1b and ad6s1b independently. =A0So I > have root on mirror/gm0a (no soft-updates), var on mirror/gm0d > (with soft-updates), and a gjournal on mirror/gm0e, with a newfs > -J partition on mirror/gm0e.journal > >> Its not as easy as a >> gmirror label ... >> gjournal label ... >> You gotta check the bsdlabel each time to make sure the c slice and >> additional slices are the correct size. > > I didn't think that GEOM layers needed to have a bsdlabel each, > and newfs is happy enough (I think) to sit on an unlabelled GEOM > provider. =A0Certainly the examples in the gjournal, gmirror and > mdconfig man pages seem to suggest that newfs'ing straight onto > one of them is the way to go. > >> If you do decide to do it again, gpt made it really easy. > > What's a gpt? =A0Neither man nor bash know about it on my system. > >> Did you use newfs -J to format the slices/journal? > > Yup. > > Thanks for the help and suggestions! > > Cheers, > > -- > Andrew > Can you show me a print out of gjournal list and bsdlabel /dev/mirror/gm0e.journal And any other .journal you have Just want to double check something. Regards David N
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