Date: Sat, 12 Jul 2008 00:39:03 +0530 From: "Tapan Chaudhari" <tapan.list@gmail.com> To: freebsd-geom@freebsd.org Subject: Re: Can GEOM be used to intercept the I/o calls to an existing mounted device? Message-ID: <482257ad0807111209g20cdb0f6j9f7000fd57a7287a@mail.gmail.com> In-Reply-To: <482257ad0807111129i66ac4372sbc9b4d4ef7675e9d@mail.gmail.com> References: <482257ad0807100541s2d2c3d1eo6cd57c3a1bc338d1@mail.gmail.com> <200807102309.03191.mark@legios.org> <482257ad0807100655u1a5c660awfad05564e40e9a95@mail.gmail.com> <482257ad0807111129i66ac4372sbc9b4d4ef7675e9d@mail.gmail.com>
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Hi, I got the problem resolved of not getting mails. It was the stupid of me that changed the settings :-).. I have unchecked the digest. Did Ivan sent some attachment with the mail? An attachment was scrubbed in the digest I received. Sorry for the trouble but still, can anyone resend it? Expecting some help regarding "interception mechanism" from all of you. Thanks, --Tapan. On Fri, Jul 11, 2008 at 11:59 PM, Tapan Chaudhari <tapan.list@gmail.com> wrote: > Hey guys, > First of all, I was not able to receive your replies to my mail. I > don't know the reason but I am already subscribed to the list. I got to know > about your replies from the digest i received today. I have written a mail > to the mailing list owner describing this problem. Hope this does not happen > again. > > > Well regarding GEOM as Poul mentioned he has already done this interception > mechanism in GEOM, Poul can you please help me out by giving some directions > as to how to move ahead and implement the interceptions of i/o to a > particular device? I would be really happy to get any help regarding the > interception mechanism. > > Thanks, > --Tapan. > > > On Thu, Jul 10, 2008 at 7:25 PM, Tapan Chaudhari <tapan.list@gmail.com> > wrote: > >> Thanks Mark, but unmounting will anyways work. But the problem here will >> be, a new device "/dev/mirror/gm0" and "/dev/mirror/gm0s1" will be created >> after :- >> >> #gmirror label -v -n -b round-robin gm0 /dev/md0 >> #gmirror load >> #gmirror configure -a gm0 >> >> and "/dev/md0s1" gets deleted. >> Now I will have to mount the new device "/dev/mirror/gm0s1" to get my >> original contents. >> Can't I do it on the fly while the device is already mounted? I just want >> that all the calls going to the device "/dev/md0s1" first come to me and >> then it goes to the original device. In short intercepting the i/o calls. Is >> there some way I can achieve this? >> >> Thanks, >> >> >> On Thu, Jul 10, 2008 at 6:39 PM, Mark Gladman <mark@legios.org> wrote: >> >>> On Thursday 10 July 2008 22:41:25 Tapan Chaudhari wrote: >>> > Hi All, >>> > I am a newbie to FreeBSD and GEOM. I wanted to intercept the i/o >>> calls >>> > going to a particular mounted device by writing some driver. >>> > I came across geom and thought it might work. I tried to create a new >>> > device, mount it and then tried using gmirror to mirror the device :- >>> > >>> > #dd if=/dev/zero of=file1 bs=1M count=10 >>> > #dd if=/dev/zero of=file2 bs=1M count=10 >>> > #mdconfig -f file1 >>> > #mdconfig -f file2 >>> > #fdisk -B /dev/mirror/md0 >>> > #newfs /dev/mirror/md0s1 >>> > #mkdir /mnt/mirror0 >>> > #mount /dev/mirror/md0s1 /mnt/mirror0/ >>> > >>> > #gmirror label -v -n -b round-robin gm0 /dev/md0 >>> > gmirror: Can't store metadata on /dev/md0: Operation not permitted. >>> > >>> > It gave me this error "gmirror: Can't store metadata on /dev/md0: >>> Operation >>> > not permitted." >>> > >>> > Am I doing something wrong? Or GEOM does not permit me intercept the >>> i/o >>> > calls? If not geom, is there any other mechanism by which I can achieve >>> it? >>> > >>> > >>> > Thanks, >>> > --Tapan. >>> > _______________________________________________ >>> > freebsd-geom@freebsd.org mailing list >>> > http://lists.freebsd.org/mailman/listinfo/freebsd-geom >>> > To unsubscribe, send any mail to "freebsd-geom-unsubscribe@freebsd.org >>> " >>> >>> Hey, >>> >>> You're attempting to set up gmirror on a mounted device. >>> Unmount /dev/mirror/md0s1 then retry the gmirror command and it should >>> work. >>> >>> Cheers! >>> Mark >>> >> >> >
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