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From YouTube: December 2020 OpenZFS Leadership Meeting
Description
At this month's meeting we discussed: Forced export; RAIDZ expansion performance; visibility of .zfs/snapshot.
meeting notes: https://docs.google.com/document/d/1w2jv2XVYFmBVvG1EGf-9A5HBVsjAYoLIFZAnWHhV-BM/edit
A
A
A
A
C
C
A
A
B
A
A
B
And
importantly,
if
you
have
a
second
or
third
or
other
pools
running,
they
can
continue
to
move
forward.
Whereas
if
the
unlucky
pool
happens
to
suspend
while
holding
things
like
the
namespace
log,
then
you
can't
even
run
zfs
list
until
you
deal
with
the
suspended
pool
and
that
you
know
degrades
the
user
experience.
A
A
There
are
some
known
issues
with
like
if,
if
you
crash
at
the
at
the
wrong
time
or
if
devices
become
degraded
like
like
you,
lose
a
disc
while
you're
in
the
middle
of
the
expansion
that
we
still
need
to
address,
but
aside
from
those
corner
cases,
it
basically
totally
works.
It's
pretty
slow
in
some
for
some
things,
but
those
are
all
things
that
we
we
you
know.
We
know
how
to
address
and
we're
working
on
them.
A
So
if
folks
want
to
want
to
do
more
testing
on
that,
that
would
be
great.
I
was
planning
to
get
out
like
a
an
alpha
like
a
I
guess.
The
current
one
is
an
alpha
release.
I
was
planning
to
put
out
like
a
beta
by
the
end
of
the
year
that
draw
more
attention
to
the
fact
that
we
made
all
this
progress
yeah.
A
It
should
work
so
the
latest
things
that
we've
done
are
getting
it
so
that,
after
you
do
the
expansion,
the
writes,
are
happening
with
the
new
data
to
parity
ratio,
which
means
that
it
takes
up
less
space
on
disk
and
also
the
performance
is
good,
is
better.
You
get
basically
the
normal
performance
rather
than
you
know.
When
you're,
when
you're
reading
or
writing
things
that
are
like
misaligned,
then
it
has
to
generate
a
lot
more
cios
there's
actually
some
work
that
I'm.
A
The
parity
is
changing
to
a
different
disk
rather
than
like
the
parity
all
be
on
one
disk.
For
that,
given
block
so
the
way
we
deal
with,
that
is
by
creating
a
bunch
of
zios
like
one
for
each
sector
essentially
and
then
like
stitching
it
all
back
together,
which
works
great
and
integrates
well
with
the
existing
code.
A
But
just
man
like
allocating
and
de-allocating
all
of
those
zioties
and
even
all
of
the
abd's
associated
with
them
is
very
you
know
it's
very
slow,
like
it
uses
a
lot
of
cpu
to
do
that
because
you're
talking
about
like
for
128k
io,
let's
say
if
it's:
if
it's,
if
the
layout
matches
the
like
the
logical
and
physical
match,
then
you're
you're
only
dividing
that
128k
into
a
five
disk.
So
you
have
like
five
zios
versus
you
know.
A
C
A
Yeah,
I've
done
a
bunch
of
benchmarking
on
that
and
we
we
have
a
bunch
of
work
in
progress,
that's
like
kind
of
rough
and
ready
quality,
but
it
works
and
it
improves
the
performance
to
be
pretty
good.
I
don't
remember
the
numbers
off
the
top
of
my
head,
but
it
was
like
more
than
half
the
normal
performance,
so
you
know
it
wasn't
like
all
the
way
to
normal
to
normal
performance,
but
it
was
pretty
close,
and
this
is
like,
I
think,
a
system
with
like
eight
cpus
driving.
A
So
the
work
I'm
breaking
out
right
now
is
basically
being
able
to
like
pre-allocate
the
abdt
have
that
embedded
in
another
data
structure
and
so
like
when
you're
creating
an
abd,
that's
just
like
referencing
another
one.
Then
you
can
provide
the
actual
abd
struct
that'll
initialize.
In
that
way.
That
way,
you
don't
have
to
do
the
like.
You
don't
have
to
do
the
camera
malloc
for
the
apdt
itself,.
C
A
C
C
C
Well,
even
in
production,
we
shall
we
have
right
now,
one
the
case
we
are
investigating
and
they
have
performance
problems
and
cpu's
age
going
about
50
on
quite
decent
hardware,
and
there
we
have
something
like
a
16k
rate,
z
on
top
of
five
white
or
16k.
The
walls
on
top
of
five
white
raid
z,
so
even
chunking
at
four
or
eight
k,
is
pretty
significant.
It's
significantly
increased
number
of
ios
overhead,
so
even
that
is
not
perfect
and
great
yeah.
A
But
you
should
get,
but
with
redzy
expansion
you
should
still
get
better
performance
than
what
you're
talking
about
as
long
as
you
have
large
block
size
because
of
the
like
integrated
aggregation
in
the
at
the
raid
z
level.
So
you
won't
be
doing
zios
for
every
4k.
You'll
only
be
doing
the
zio.
You
know
for
the
whole
block.
A
A
A
C
A
C
C
Science,
we
don't
have
other
things.
I
have
one
quick,
freebies
equation.
Does
anybody
know
why
we
have
tunable
for
abd
block
size
because,
obviously
setting
it
less
than
page
size
make
no
any
sense
signs
it
automatically
drops
to
smaller
blocks.
You
even
needed
and
setting
is
higher,
is
just
killer
for
vm
subsystem
for
uma
caches.
B
C
B
C
B
B
Some
recent
cleanup
changed
the
in
global
zone
macro
to
use
kerprock
instead
of
cur
thread,
so
that
code
would
need
to
be
updated
to
fake
the
credentials
of
the
process.
Instead
of
the
thread,
but
the
question
is:
is
it
okay
to
do
that?
It's
how
freebsd
has
always
done
it.
It
seems,
but
does
it
make
sense
to
allow
regular
users
to
be
able
to
mount
snapshots
and
especially,
do
that
from
inside
of
a.
B
B
It
does
and
then
they
could
mount
it
normally
there.
I
don't
actually
know
how
the
zfs
stuff
responds
when
it's
a
delegated
data
set
in
this
particular
user's
use
case.
The
data
set
is
only
is
mounted
on
the
host
and
just
happens
to
be
inside
the
sage
route
that
the
jail
is
based
on,
so
the
jail
itself
doesn't
have
visibility
on
that
data
set
like
it.
Doesn't
you
can't
zfs
list
the
data
set
that
it's
ending
up
mounting.
D
Yeah
I'd
have
to
go
back
and
look
on
a
lumos
for
what
it
does
for
zones
correct
or
actually
the
other
thing,
because
my
initial
thought
would
be
is:
if
it's
delegated
then
yeah
it
should
work.
But
if
it's
just
you
know
a
subdirectory
of
a
data
set,
you
know
it's
maybe
a
little
different,
but
I
can't
remember
now
it's
one
of
those
things
where
you
just
never
think
about
it.
How.
B
Yeah,
I
never
thought
about
how
you
know
a
user
in
a
jail
mount
being
able
to
access,
zfs
snapshot
worked
or
the
fact
that
nothing
ever
seems
to
unmount
those
they
get
mounted
with
the
ignore
flags,
so
the
regular
mount
command
doesn't
display
them.
But
if
you
do
mount
v,
you
can
see
the
list
of
them.
B
And
so
the
zfs
is
visible,
it's
just
with,
because
the
credential
hack
isn't
working
right.
Now,
if
you
go
in
there
and
try
to
you
know
you
can
ls
and
see
the
list
of
snapshots.
But
if
you
do
ls-l,
you
can't
actually
f-stat
the
the
directory,
because
you
don't
have
permission
basically
because
it
fails
to
mount
it
when
it
tries
to
mount
it
to
to
get
the
f-stat.
B
B
B
B
She
made
the
changes
for
the
in
global
zone
to
be
able
to
not
go
through
like
two
functions
and
three
macros
to
to
find
out
which
jail
you're
in
a
much
more
direct
route.
It
looks
much
nicer.
It's
just
the
hack,
only
fakes,
the
credentials
for
the
thread,
not
the
whole
process,
and
now
we
examine
the
credentials
of
the
process.
A
A
C
Yeah,
if
it's
even
if
it's
85
of
performance
not
of
spent
cpu,
that's
not
as
terrible,
especially
it's
for
for
the
worst
case,
who
could
tell
yeah?
I
I
same
as
I
I
always
discourage
people
from
removing
vdfs
unless
they
really
need
it.
I
guess
I'll
still
remain.
It's
got
a
shorter
size,
but
it's
good
to
have
it
even.