getting to 4K disk blocks in ZFS

[Peter Wemm]

On Thursday, September 11, 2014 09:24:41 AM Andriy Gapon wrote:
> On 11/09/2014 04:22, Steven Hartland wrote:
> > ----- Original Message ----- From: "Aristedes Maniatis" <ari at ish.com.au>
> > 
> >> Should the FreeBSD project change this minimum in the next release?
> >> There seems to be no downside and a huge amount of pain for people
> >> who stumble along with the defaults not knowing what a mess they are
> >> creating to solve later.
> > 
> > The downside is wasted space which can be significant and hence when
> > I last suggested just this it was unfortunately rejected.
> > 
> > We still maintain a local patch to our source tree which does just
> > this because, as you've mentioned, we don't want the pain so its
> > easier to just run everything as 4k.
> 
> Another downside is 1/4th of uberblocks, 32 vs 128.
> Also, automatic sector size detection works great for me and I've never had
> a need to manually tweak ashift.

Unfortunately, I have.  Same drive connected two different ways:

da12 at mps1 bus 0 scbus1 target 11 lun 0
da12: <ATA ST4000VN000-1H41 SC43> Fixed Direct Access SCSI-6 device 
da12: 600.000MB/s transfers
da12: Command Queueing enabled
da12: 3815447MB (7814037168 512 byte sectors: 255H 63S/T 486401C)

ada1 at ahcich1 bus 0 scbus3 target 0 lun 0
ada1: <ATA ST4000VN000-1H41 SC43> ATA-8 SATA 3.x device
ada1: 600.000MB/s transfers (SATA 3.x, UDMA6, PIO 8192bytes)
ada1: Command Queueing enabled
ada1: 3815447MB (7814037168 512 byte sectors:  16H 63S/T 16383C)
ada1: quirks=0x1<4K>

The 4k flag is missing when it's on the sas controller.  The Ident strings are 
changed.

This came up elsewhere recently.

-- 
Peter Wemm - peter at wemm.org; peter at FreeBSD.org; peter at yahoo-inc.com; KI6FJV
UTF-8: for when a ' or ... just won\342\200\231t do\342\200\246
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