RE: nvd->nda switch and blocksize changes for ZFS

Frank Behrens <frank_at_harz2023.behrens.de> wrote on
Date: Sat, 23 Sep 2023 16:31:40 UTC :

> I created a zpool with a FreeBSD-14.0-CURRENT on February. With 
> 15.0-CURRENT/14.0-STABLE from now I get the message:
> 
> status: One or more devices are configured to use a non-native block size.
>         Expect reduced performance.
> action: Replace affected devices with devices that support the
>         configured block size, or migrate data to a properly configured
>         pool.
>         NAME        STATE     READ WRITE CKSUM
>         zsys        ONLINE       0     0     0
>           raidz1-0  ONLINE       0     0     0
>             nda0p4  ONLINE       0     0     0  block size: 4096B 
> configured, 16384B native
>             nda1p4  ONLINE       0     0     0  block size: 4096B 
> configured, 16384B native
>             nda2p4  ONLINE       0     0     0  block size: 4096B 
> configured, 16384B native
> 
> I use:
> nda0: <Samsung SSD 980 1TB ..>
> nda0: nvme version 1.4
> nda0: 953869MB (1953525168 512 byte sectors)
> 
> I cannot imagine, that the native blocksize changed. Do I really expect 
> a reduced performance?
> Is it advisable to switch back to nvd?

Looking at: https://www.techpowerup.com/ssd-specs/samsung-980-1-tb.d58

it reports (indifferent places on the page):

QUOTE
Page Size: 16 KB

Notes
NAND Die:
A Dual-plane Die with 2 sub-planes with 8 KiB pages in order to improve performance through paralellism.
Endurance: Could be from 1.500 to 3.000 P.E.C. depending on NAND binning
END QUOTE

That "A Dual-plane Die with 2 sub-planes with 8 KiB pages", for a total
of 16 KB, does suggest to me that the new messages have a chance of
being correct about there being a tradeoff. (But I'm no expert in the
area.)

===
Mark Millard
marklmi at yahoo.com