getting to 4K disk blocks in ZFS

[Karl Denninger]

On 9/11/2014 4:06 AM, Pete French wrote:
>> This may never hit you, but ZFS is built on the assumption, that it
>> cannot happen at all, which is no longer true with 4KB drives that
>> are used with ashift=9.
> Have just been reading this thread, and as people are suggesting
> moving ashift from 9 to 12, doesnt using use 512B drives with
> ahift=12 also violate this ? Or is it smart enough ot know that
> the underlying sectors are separate ?
>

No, because in order for the "write" (as ZFS sees it) to succeed all of 
them must succeed.

The problem comes when the *drive* (or controller) does a 
read-replace-write, because ZFS is unaware of the underlying act and 
"silent" corruption can thus (at least theoretically) happen.

-- 
Karl Denninger
karl at denninger.net <mailto:karl at denninger.net>
/The Market Ticker/
-------------- next part --------------
A non-text attachment was scrubbed...
Name: smime.p7s
Type: application/pkcs7-signature
Size: 2711 bytes
Desc: S/MIME Cryptographic Signature
URL: <http://lists.freebsd.org/pipermail/freebsd-stable/attachments/20140911/cfba83ab/attachment.bin>