exictent zroot re-alignment to 4K

[krad]

is it just an alignment problem or are you ashift=9 (zdb zroot | grep
ashift) as well? If you are already ashift=12, you can probably skip all
the zfs send and receive bits and just attach it as a mirror, then drop out
the original drive, repartition, install boot blocks and reattach.


On 27 August 2013 18:27, <kpneal at pobox.com> wrote:

> On Tue, Aug 27, 2013 at 06:11:27PM +0300, Zeus Panchenko wrote:
> > -----BEGIN PGP SIGNED MESSAGE-----
> > Hash: SHA1
> >
> > hi all,
> >
> > please, I really need help ...
> >
> > recently I noticed that my netbook HDD has 4K phys sectors and I think
> > it is worth to use that (is it really worth indeed?)
> >
> > I have FreeBSD 9-STABLE running well on it already but when it was
> > installed, the alignment was not done properly ...
> >
> > - --------------------------------------------------------------------
> > what I have:
> >
> > > uname -a
> > FreeBSD 9.1-STABLE #17 r250823: Mon May 20 19:39:19 EEST 2013 amd64
> >
> > > smartctl -a /dev/ada0
> > Model Family:     Western Digital Scorpio Black (AF)
> > Device Model:     WDC WD5000BPKT-60PK4T0
> > Serial Number:    WD-WXJ1A61P0560
> > User Capacity:    500,107,862,016 bytes [500 GB]
> > Sector Sizes:     512 bytes logical, 4096 bytes physical
> >
> > > gpart show ada0
> > =>       34  976773101  ada0  GPT  (465G)
> >          34          6        - free -  (3.0k)
> >          40        128     1  freebsd-boot  (64k)
> >         168   33554432     2  freebsd-swap  (16G)
> >    33554600  943218528     3  freebsd-zfs  (449G)
> >   976773128          7        - free -  (3.5k)
>
> Unless I'm doing the math wrong it looks like your swap and zfs partitions
> are already 4k aligned. So there's no need to redo your partitions. Just
> skip ahead to the part where you do the ZFS stuff.
>
> I've never setup a machine with a ZFS root so I can't say if that part is
> correct.
>
> > is ZFS version have to be the same on both systems (the one to be
> > aligned is shown as 5000 (after `zpool upgrade -a') while the one all
> > that stuff to be performed at is 28)?
>
> I assume you are doing a zfs send to a file on a remote machine? Or, you
> are doing the send+receive on the helper machine? In either of those cases
> you just need the machine that you do the restore on to be new enough to
> handle ZFS version 5000. The version of the pool holding the file you are
> restoring from does not matter.
>
> --
> "A method for inducing cats to exercise consists of directing a beam of
> invisible light produced by a hand-held laser apparatus onto the floor ...
> in the vicinity of the cat, then moving the laser ... in an irregular way
> fascinating to cats,..." -- US patent 5443036, "Method of exercising a cat"
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