Date: Sat, 16 Oct 2010 19:10:14 -0700 From: Freddie Cash <fjwcash@gmail.com> To: Pawel Jakub Dawidek <pjd@freebsd.org> Cc: freebsd-fs@freebsd.org Subject: Re: Converting a non-HAST ZFS pool to a HAST pool Message-ID: <AANLkTi=umVeJmYvYrz1eA48gnbBjKf8in1HbcS3m8SnL@mail.gmail.com> In-Reply-To: <20101016222833.GA6765@garage.freebsd.pl> References: <AANLkTin07ZvB%2Bj2sqdi2bSS_4MwEvEcRPgK-0qc%2Brch4@mail.gmail.com> <20101016222833.GA6765@garage.freebsd.pl>
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On Sat, Oct 16, 2010 at 3:28 PM, Pawel Jakub Dawidek <pjd@freebsd.org> wrot= e: > On Fri, Oct 15, 2010 at 11:37:34AM -0700, Freddie Cash wrote: >> Has anyone looked into, attempted, or considered converting a non-HAST >> ZFS pool configuration into a HAST one? =C2=A0While the pool is live and >> the server is in use. =C2=A0Would it even be possible? >> >> For example, would the following work (in a pool with a single raidz2 >> vdev, where the underlying GEOM provider is glabel) >> =C2=A0 - zpool offline 1 drive =C2=A0(pool is now running degraded) >> =C2=A0 - configure hastd in master mode with a single provider using the >> "offline" disk (hast metadata takes the place of glabel metadata) > > HAST metadata takes much more space than glabel metadata. The latter > takes only one sector, while the former depends on provider size, but we > have to keep entire extent bitmap there, so definitely more than one > sector. Hrm, darn. So close. :) >> =C2=A0 - zpool replace the offline drive using the /dev/hast/whatever pr= ovider >> =C2=A0 - wait for ZFS to resilver the device >> =C2=A0 - repeat for each disk in the vdev >> >> Is it possible to change the hast configuration and reload hastd to >> pick up new providers, without restarting it? =C2=A0Without losing the >> /dev/hast devices? =C2=A0Or would it require a restart, which would caus= e >> the /dev/hast/* devices to disappear, thus b0rking the pool? > > It is possible in 8-STABLE. Good to know. >> Just wondering how hard it's going to be to move from our current >> setup (backup server 1 rsync'd to backup server 2) to a HAST setup >> (server 1 hast master with server 2 hast slave). >> >> If the above won't work, then I guess I'll have to grab a third >> storage box, configure that as a hast box, copy the data over, destroy >> server 2, configure it as a hast box, and let them sync. > > I'm afraid you have to backup your pool, recreate it on HAST provider > and recover. That's what I figured, and why I thought I'd post before attempting it. :) Thanks for the info. --=20 Freddie Cash fjwcash@gmail.com
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