[OpenIndiana-discuss] trying to get 4K aligned root pool on ESX

Steve Goldthorpe OpenIndiana at waistcoat.org.uk
Mon Aug 19 09:37:54 UTC 2013


Think I've figured it out myself.  As my disks are virtual, I should just
be able to remove them from the machine and change their geometry to
X/255/32 rather than Y/255/63 and things should be aligned.  Done the maths
and the new partition size should be just slightly bigger so I shouldn't
have to rebuild the machines (just remove and attach mirrors).

i.e. in my vmdk file
RW 27262976 VMFS "tub_1-flat.vmdk"
..
ddb.geometry.sectors = "63"
ddb.geometry.heads = "255"
ddb.geometry.cylinders = "1697"

INT(27262976/63/255) = 1967
INT(27262976/32/255) = 3341

so change vmdk to
ddb.geometry.sectors = "32"
ddb.geometry.heads = "255"
ddb.geometry.cylinders = "3341"

3341*255*32 > 1697*255*63 :-)

I'll have a play tonight...

-Steve


On 18 August 2013 17:23, Steve Goldthorpe <OpenIndiana at waistcoat.org.uk>wrote:

> No matter what I try I can't seem to get a 4K aligned root pool using the
> OpenIndiana installer (oi151-a7 live image).
> I'm using ESXi using 4K aligned disks.  VMware ensures the virtual disks
> are 4K aligned and I can get the root pool 4K aligned by fudging sd.conf on
> the live image.
>
> cd /kernel/drv
> echo 'sd-config-list =' >> sd.conf
> echo '  "VMware","physical-block-size:4096";' >> sd.conf
> update_drv -vf sd
>
> When he install starts zdb shows that i've got ashift=12 and so that part
> is OK however on the rpool the installer creates, it always use partition 0
> for the rpool and starts that on cylinder 1.  As it thinks the geometry is
> 255 heads & 63 sectors/track this will surely not be aligned.  Do I have to
> fudge the geometry too somehow?
>
> I think none root pool disks will be fine as I can use EFI labels and
> spectify ashift=12.
>
> Any ideas?
>
> -Steve Goldthorpe
>


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