gptzfsboot and 4k sector raidz

Daniel Mayfield dan at 3geeks.org
Thu Sep 1 16:30:27 UTC 2011


On Sep 1, 2011, at 7:56 AM, Trent Nelson wrote:

> On 01-Sep-11 2:11 AM, Daniel Mayfield wrote:
>> I just set this up on an Athlon64 machine I have w/ 4 WD EARS 2TB
>> disks.  I followed the instructions here:
>> http://www.leidinger.net/blog/2011/05/03/another-root-on-zfs-howto-optimized-for-4k-sector-drives/,
>> but just building a single pool so three partitions per disk (boot,
>> swap and zfs).  I'm using the mfsBSD image to do the boot code.  When
>> I reboot to actually come up from ZFS, the loader spins for half a
>> second and then the machine reboots.  I've seen a number of bug
>> reports on gptzfsboot and 4k sector pools, but I never saw one fail
>> so early.  What data would the ZFS people need to help fix this?
> 
> FWIW, I experienced the exact same issue about a week ago with four new WD EARS 2TB disks.  I contemplated looking into fixing it, until I noticed the crazy disk usage with 4K sectors.  On my old box, my /usr/src dataset was ~450MB (mirrored 512-byte drives), on the new box with the 2TB 4k sector drives, /usr/src was 1.5-something GB.  Exact same settings.

I noticed that the free data space was also bigger.  I tried it with raidz on the 512B sectors and it claimed to have only 5.3T of space.  With 4KB sectors, it claimed to have 7.25T of space.  Seems like something is wonky in the space calculations?

daniel


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