Re: Hand on gmirror (Was: Re: gmirror bugs, how many?)

From: Pawel Jakub Dawidek (pjd_at_FreeBSD.org)
Date: 11/29/04

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    Date: Mon, 29 Nov 2004 16:11:27 +0100
To: Jo?o Carlos Mendes Luís <jonny@jonny.eng.br>

    On Mon, Nov 29, 2004 at 12:52:40PM -0200, Jo?o Carlos Mendes Luís wrote:
    +> >+> Indeed, the -h option is what I wanted and the "bug" is in the
    +> >+> manual. What would happen if I change the disc ID in this case?
    +> >
    +> >Your disk will not be detected as a mirror component, because hardcoded
    +> >name is different.
    +>
    +> Oops. Is there a check for that? For example, let's say that ad0s1 got
    +> renamed to ad1s1, and hardcoded a reference to ad0s1. In this case,
    +> there is a disk called ad0s1 in the system. Is gmirror smart enough in
    +> this case?

    In this case ad1s1 will not be connected to the mirror (but don't worry,
    ad0s1 will not be connected as well).

    +> >+> sigesc::root jcmendes [553] disklabel mirror/vol0
    +> >+> # /dev/mirror/vol0:
    +> >+> 8 partitions:
    +> >+> # size offset fstype [fsize bsize bps/cpg]
    +> >+> a: 16498864 16 unused 0 0
    +> >+> c: 16498880 0 unused 0 0 # "raw" part,
    +> >+> don't edit
    +> >+> sigesc::root jcmendes [554]
    +> >+>
    +> >+> Seems good until now. Except for the offset 16 of the "a" partition.
    +> >+> Is this necessary? The man page says that the only sector reserved
    +> >+> for metadata is the provider's last one.
    +> >
    +> >Ehh, "blame" disklabel(8). First 16 sectors are reserved for boot code.
    +>
    +> And why this does not happen with ad0s1, etc?

    I think it should, only using sysinstall for this will not allocate those
    sectors. Anyway, it has nothing to do with gmirror. 

    -- 
Pawel Jakub Dawidek                       http://www.FreeBSD.org
pjd@FreeBSD.org                           http://garage.freebsd.pl
FreeBSD committer                         Am I Evil? Yes, I Am!

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