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Description
Presented by: Anthony D'Atri
Full Ceph Month schedule: https://pad.ceph.com/p/ceph-month-june-2021
A
A
Start
with
cost
tlc
excuse
me
still
awake
getting
my
throat
up
in
the
morning,
qlc
tc
over
crossover
soon
or
today,
they're
competitive.
Now,
especially
if
you
consider
some
subtle
factors
that
some
of
the
online
tco
calculators
don't
include
like
the
impact
on
your
service,
you
know
how
well
your
service
can
run
with
hdds
some
people
short
stroke,
hdds
or
limit
the
size
of
the
hdds
that
they'll
use
because
of
the
interface
bottlenecks
and
the
recovery
times
that
they
experience
with
hdds.
A
A
A
A
These
are
available
capacities
up
to
30
terabytes
and
you
can
fit
up
to
1.5
petabytes
raw
space
per
rack
unit
with
the
the
ruler
e1.led
sff
drives
that
you
know
having
come
from
a
time
cough
off
when
my
first
hard
drive
was
a
five
megabyte,
14
meg
pack,
that
it
that
just
blows
me
away
the
density
that
we
can
get
today
and
the
advantage
to
iops
that
that
ssds
give
you
allows
flexible
capacity
provisioning
where
you
don't
have
to
provision
for
iops
anymore.
You
can
provision
for
your
capacity.
A
A
This
sata
drives
saturated
about
550
megabytes
per
second
and
the
pci
gen4
nvme
interface
crushes
the
the
side
of
bottleneck.
Two
more
osbs
per
device
improved
throughput,
iops,
intel
latency.
This
is
common
practice
with
nvme
drives.
The
nvme
interface
allows
you
to
do
that
and
you
know
work
around
some
of
the
serializations
and
the
code
and
so
forth.
B
A
A
Replacing
hdds
with
intel
qoc
ssds
for
bucket
data
can
markedly
improve
your
qos
and
serviceability
of
your
clusters.
Reliability
and
endurance
qlc
reliability
is
better
than
you
think,
and
it's
actually
more
than
you
need
it
turns
out.
Most
ssd
failures
are
firmware
unless
you
can
fix
them
on
the
drive.
A
You
know
which,
in
my
experience,
is
not
as
true
with
hdds
and
studies,
show
that
99
of
ssds
never
actually
exceed
15
of
their
rated
endurance,
which
was
a
bit
of
an
eye
opener.
Having
come
from
an
assumption
that
you
needed
one
theoretical
drive
rate
per
day
to
do
rbd,
for
example,
the
rgw
service,
you
know
in
one
case
has
been
calculated
for
seven
years
of
endurance
using
the
previous
generation
qlc.
A
Revival,
endurance
get
with
the
program
erase
cycle,
that's
a
nan
joke
everybody.
Google,
the
30,
terabyte
intel
ssd,
d5p5316
qlcssd
much
like
the
lydium
q38
space
modulator
is
rated
at
over
22
petabytes
of
iu,
aligned,
random
rights,
one
drive
rate
per
day,
7.68
terabyte
tlc
ssd,
is
rated
at
less
than
15
petabytes
of
4k
random
rights.
A
A
A
A
Optimize
endurance
and
performance
with
with
cue
it
with
these
cute
course
iu,
qlc
ssds
is
beneficial
to
align
the
bluester
min
alex
size
to
the
the
iu
size.
The
indirect
union
size
of
the
drive
64k
for
the
new
drives
16k
for
the
drives
that
are
already
out
in
the
field
right:
the
lines
to
iu
boundaries
on
multiples,
enhanced
performance
and
endurance,
and
you
know
simply
aligning
with
bluester
menelik
size.
A
A
You
know
very
well,
align
your
metadata,
but
exactly
turns
out
to
be
a
small
percentage
of
the
overall
workload
and
that
doesn't
have
a
large
impact
on
the
drives
and
durability,
because
again
because
the
drives
are
so
big,
some
example
use
cases,
rgw
large
objects
rbd
when
used
for
backup
archive
and
media
I've
experienced
rbd
used
both
ways.
Cffs
has
a
four
megabyte
block
size
and
it
seems
as
though
dlc
could
be
a
good
fit
for
us
ffs,
that's
testing.
We
still
need
to
do
next
slide
additional
optimizations.
A
I
believe
neither
of
those
is
is
by
default
and
they
may-
and
you
know
they
should
give
us
better
performance
and
better
right
amplification
at
the
expense
of
you
know,
using
a
bit
more
space.
But
again
when
you
have
30
terabytes,
maybe
that's
a
maybe
that's
a
good
trade-off.
Their
other
roxdb
tuning
may
be
beneficial.
A
Another
another
route
is
to
use
optane
to
accelerate
wall
and
db
on
a
separate
device
or
engage
in
other
right
shaping
activities.
Crimson,
you
know,
may
bring
us.
You
know
some
optimizations
for,
of
course,
iu
drives
as
well
and
for
gw.
We're
looking
at
separate
pools
for
large
and
small
objects
with
esc,
and
especially
with
raising
the
blue
storm
magnetic
size,
backup,
rgw's
fit
for
small
objects,
isn't
great
and
you
can
have
a
bunch
of
strands
of
space.
A
B
C
D
A
A
The
30
terabytes
and
super
micro
offers
in
this
fine
print
that
you
can't
read.
Super
micro
offers
a
system
that
gets
you
around.
1.4
terabyte
one
terabyte
raw
and
somebody
else
that
I
found
offers
a
system
that
has
additional
ruler
drive
slots
on
the
back,
and
so
you
know
it's
a
fairly
deep
chassis,
because
you
have
these
long
drive
bays
on
the
front
and
the
back.
A
B
A
C
Okay,
yeah,
I
was
sorry
I
had
some
technical
issues
at
the
beginning.
First
is
the
audio.
Now
is
the
microphone,
but
so
this
is
you
young
hi
sage.
So
yes,
I
mean
no.
This
is
not
a
zns
device.
This
qrc
drive
is
just
that
anthony
introduced
today
is
block
device
only,
but
it's
using
the
course
in
direction,
meaning
that
you
know
it's
optimized
for
larger
block
size
than
the
traditional
4k.
C
B
Cool
okay,
okay,
thanks
a
couple
slides
after
that,
you
mentioned
over
provisioning
to
to
balance
against
durability
versus
capacity.
Is
that
is
that,
like
an
explicit
management
operation
that
you
have
to
instruct
the
device
to
do
that,
or
is
it
just
a
matter
of
writing
to
a
constrained
set
of
lbas
in
order
to
avoid
that
trade-off?.
B
A
B
C
I
I
can't
take
this
yeah,
so
the
afr
target
for
ssd
include
all
the
failures,
not
only
former,
although
former
may
take
the
majority
of
it.
There's
also,
you
know
hardware
failure
and
also
you
know
different
kind
of
failures
for
for
ssd,
usually
for
intel's
nand
ssd.
We
have
an
annual
failure
rate
target
of
less
than
0.44.
C
So
this
floating
gate
technology
is
really
good
for
having
large
capacity
nand
components
as
well
as
have
really
fast
nand
components
and
also
reliable
nand
component.
That's
you
know,
have
a
really
good
retain
retention
rate
of
their
data.
So
that's
why
you
know
qlc
intel
skill.
Cssc
has
a
really
low
annual
failure
rate,
which
is
quite
different
from
what
the
market
think
usually
when
they
think
about
qlc.
They
think
about
the
quality
is
lower
than
tlc,
which
is
not
true
at
all.
B
Yes,
yep,
I
guess
maybe
it's
just
yeah
one
more
back
one
more.
The
the
question
was
is
yeah.
There
we
go
is
the
is
the
iu,
something
that
is
exposed
in
the
was
it
the
kernel
block,
device
properties
and
sysfs
or
wherever
it
is,
though
you
can
tell
what
the
preferred
right
unit
size
is
like.
Is
this
something
that
we
can
have
make
blue
store
automatically
detect
of
the
device
so
that
it
automatically
sets
blue
storm
analog
size
accordingly?
Or
is
it
yes,
something
that
you
have
to
know.