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From YouTube: Allocation Classes by Don Brady
Description
From the OpenZFS Developer Summit 2018
Slides: https://docs.google.com/presentation/d/17nYRgs-TAIOPODOMaq-VwuJ0LqJHEXBfM9sUDxJUJ54/edit?usp=sharing
A
A
Conference
was
also,
in
extension,
in
that
very
room.
I
remember,
there's
done
a
whole
bunch
of
other
folks
that
are
was
who
are
here
today
talking
about
how
we're
going
to
do
allocation
classes
now,
they're
gonna
redesign
the
whole
thing
and
then
Don
did
it
implemented
all
that
and
was
finally
just
integrated
as
you
well
Friday
right,
yeah,
I'm,
Friday,
so
Don's
here
to
kind
of
give
a
recap
of
that
project
and
I
guess
what
it
took
to
get
here,
yeah!
So,
okay,.
B
Location
class
is
also
known
as
5182.
You
were
calling
the
full
requested
mat.
So
yesterday
I
think
there
was
some
Q&A
that
mentioned
allocation
classes
with
anybody
out
there
like
thinking
like
what
what
what's
an
allocation
class
anybody
like
kind
of
loss.
Okay,
good
stock
is
for
you,
so
I'm
gonna
go.
This
is
lightning
talk.
I'm
gonna
go
pretty
fast,
but
I'm
gonna
try
to
talk
about
cover.
What
what
they
are,
how
you
can
use
them,
I
think
it
takes
so
long,
and
why
doesn't
it
support?
No
wait,
just
not
right.
B
How
can
you
help
me
whatever
is
missing,
and
then
you
know
sort
of
what's
next
so
this
initially
it
was
a
feature
and
DeRay.
The
previous
talk
was.
It
was
a
sub
feature
at
D
rate,
so
we
had
dreg.
We
had
16
bank
blocks.
This
was
for
at
Intel
for
an
Aurora
supercomputer
and
we
were
anticipating
heavy,
a
workload
that
was
such
that
we
have
like
these
checkpoints
coming
in
at
16,
mega
byte
streams
and.
B
So
disparity
between
those
two
was
so
great
and
we
had
to
separate-
and
so
that's
where
this
future
came
in
existence,
I
think
even
the
pull
request
said
metadata
allocation
classes.
It
has
more
you
to
Amman
chimeric
allocation
concepts,
but
that's
sort
of
the
essence
of
what
why
we
started
doing
this
and
this
Matt
mentioned
there
was
an
early
pitch,
the
community
that,
if
it's
hackathon
and
then
we
went
from
this
metadata,
only
kind
of
very
narrow
things,
the
more
generic
hey.
B
Let's
have
a
bunch
of
class
variants
mas
data,
you
can
sort
of
separate
it
out.
You
can
actually
all
these
combinations
of
that.
Initially
there
was
refinements
along
the
way
we
decided
to
add
small
blocks.
No
someone
asked
me
to
speak
up.
Is
that
better,
it's
harder,
but
ok,
along
the
way
there
were
some
refinements.
We
added
small
support
for
small
blocks.
Again
tried
an
array
we
added
some
stats.
They
were
pretty
cool,
but
in
the
end
I'll
talk
about
it
later.
B
And
thanks
the
community
lots
of
good
good
comments
about
spooky
Beck,
so
how
many
are
familiar
with
a
slog
and
what
would
that
is
yeah?
So
the
fog,
in
essence,
is
the
the
log
data
you
want
to
put
that
into
sort
of
a
special
tier,
most
likely
an
SSD,
highly
transient
data
sensitive
to
you
know
the
latency
I
ops,
and
so
you
have
that
convention
in
CFS
today,
just
crazy,
full
you
having
the
long
device.
You
just
puts
log
in
front
of
it
and
we
set
it
up.
B
B
B
B
A
B
B
B
Here's
an
example
of
what
it
looks
like
when
you
do
example
status.
The
other
classes
will
be
listed
in
the
similar
way
like
the
logs
were
afterwards.
In
this
case,
we
have
a
deduct
here.
We
have
a
special
yummy
and
similarly
for
Z
poll
people
last
and
suppose
that
if
you
do
a
B
it'll
call
out
those
those
we
tip.
So
it's
useful.
If
you
want
to
see
it's
a
bandwidth
of
my
special
class
guy
constraining
me,
you
can
sort
of
see
see
those
that
information
for
coverage.
B
We
we
added
to
Z
test
well
by
default,
detest
like
everybody
else,
was
a
fifty
percent
at
the
time
constant
us
a
coin.
We're
gonna
do
some
special
classes.
We
have
more
control
over
that
I
introduced
with
a
new
flag,
and
you
know
I'm
welcome
to
feedback
here.
I
just
did
T
per
class,
and
then
you
can
see,
especially
because
on
especially
off,
if
you
don't
have
the
interference
and
by
default
there's
special
person
and
that
helps
us
exercise.
Basically,
another
sort
of
tidbit
is
that
there
are
no
files
or
Z
vault.
B
Indie
fest
uses
special
block
light.
I
can't
remember
all
about
mega.
It's
like
the
comments
is
like
for
testing
honking
foot,
so
we're
not
evening
files,
but
we've
changed
a
macro.
That's
used
by
that
small
preferred
class
or
referred
you
to
say
like.
Is
it
a
file
block
or
you
know
this
special
block,
but
these
issues
so
we
get
the
kirk
privilege
likewise,.
A
B
B
B
Sequel,
stat
you'll
see
things
broken
out
class.
These
little
in
this
case,
I.
Don't
think
it's
short
time,
but
but
it'll
it'll
it'll
put
a
tag
on
the
Vita.
When
you
listen
to
have
to
see-
and
that's
that's
useful
in
Z
test,
the
Z
test
will
do
guesses
as
it
goes
through.
So
you
can
sort
of
see,
hey
did
I
get
any
allocation
classes.
B
So
they
I
mentioned
I
kind
of
a
little
bit
too
earlier.
We
have
this
provision
for
small
blocks
in
the
special
class.
It's
it's
per
data
set,
so
you
can
actually
on
a
data
set,
say
I
want
up
to
this
amount
of
small
blocks.
That's
say
32k
to
go
into
the
special
class
and
that's
really
more
more
for,
like
deer,
a
deer,
a
DME
provision
to
have
some
of
the
meta
file
view
mirrors
versus
being
really
wide
stripe.
B
B
A
B
B
I
had
to
go
back
and
figure
out
like
what's
the
appropriate
context
to
to
get
the
class
there's
a
new
field
in
the
CIO
structure
that
has
the
class
and
then
I
I
mentioned
the
broken
block
stats
and
that
one
was
really
kind
of
frustrating
to
me
because
you
think
you
know,
ZFS
is
talkin
right,
you
know,
and
a
block
corner
is
I
assumed
immutable
right.
You
have
a
block,
it's
not
gonna
change,
so
on
Alec,
I
think
that
block
corner
divides,
which
ended
with
the
stats
in
and
on.
A
B
It's
not
a
beautiful,
because
he
do
you
know.
Well,
actually
he
duped
that
block
you
later
saying.
It'll
just
make
up
a
plot
one
and
make
up
like
the
levels
always
zero,
and
so
the
county
was
kidding
off
with
you
and
then
with
game
blocks.
It
further
made
it
harder
gang
blocks
tracking,
like
what's
the
actual
block
here,
so
the
code
had
more
exceptions.
B
Maintaining
that
would
have
been
too
high,
we've
been
breaking
it
and
then,
of
course,
traditional
project
management
feature
create
a
let's
put
small
blocks
in
there,
and
we
had
this
whole
feature
called
segregation
where
with
Irae,
you
can
actually
give
you
up
the
meta
slabs
that
way,
rather
than
you
know,
it's
basically
say
it's
a
separate
video
and
so
that
then
we
simplified
I.
You
talked
about
having
all
that
stuff
and
simplify
all
these
things.
A
long
ways
we're
just
taking
the
time
what
that
was.
They
were
some
ladders.
B
B
B
B
This
mirrored
thing
like
us:
there
I'm
sorry
people
and
in
dentists.
Log
is
a
concept
it's
similar
to
this,
but
instead
it's
just
basically
having
a
separate
metal
AB
for
each
one
a
year,
your
upload
videos,
then
we
can
put
slot
dated
you
can't
leverage
some
of
this
work
and,
in
the
same
way
having
custom
pluggable
allocators
are
more
in
line
with
what
kind
of
working
said
to
you
that.
B
This,
the
PDF
properties
would
be
another
way
sort
of
do
some
administration
on
this
right
now,
I
mentioned
you
can
just
say
you
can
set
it
at
create.
You
can't
change
it,
you
can
remove
it,
we've.
Let
you
on
that
the
policies
and
then
some
sort
of
policy
refinements
you
may
want
to
have
like
for
large
files,
don't
put
my
small
blocks
in
their
policies,
maybe
even
some
sort
of.
A
B
B
B
A
B
B
B
B
A
B
A
Know
I
think
this
may
be
one
of
the
only
major
features
to
be
implemented
across
multiple
companies.
So
a
visitor,
you
might
not
know,
Don
started
this
project
and
implemented
most
of
it
when
you
are
Intel,
yes
and
then
complete
it.
You
know,
I
knew
the
contract
that
you
said
and
then
you
joined
del
phix
a
year
or
so
over
here,
yeah
man,
you
know
so
I
think
del
phix
and
Intel.
For
both
you
know
working
together,
it's
just
lunch
and
this
work
for
Don
to
complete
it.