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Hello. <br>
<br>
I didnt reply your email because:<br>
<br>
I'm a DRBD user. I'm not in the DRBD Team.<br>
<br>
My english is poor.<br>
<br>
And I dont understand what is your problem, because in the email you
send the DRBD sync is aprox 680MB/s.<br>
<br>
RAID 10 to 800MB/s is a theoretical or tested value ?<br>
<br>
Do you test link connection ? What it is the real speed of your
connection ? I think that 680MB/s is good. The theoretical value in
a 10Gb/s is 1280MB/s but real depends<br>
<br>
You can test speed link connection with<br>
<br>
<a class="moz-txt-link-freetext" href="http://eggdrop.ch/projects/bwbench/">http://eggdrop.ch/projects/bwbench/</a><br>
<br>
What is you want ?<br>
<br>
more speed in sync ??<br>
<br>
<br>
<div class="moz-cite-prefix">El 08/06/15 a las 16:47, Ben RUBSON
escribió:<br>
</div>
<blockquote
cite="mid:CAGUFuyAdqt3_5hzcMBWw7tXJOkK+x0EZ5bWWY5L8ZHcW0V7aVg@mail.gmail.com"
type="cite">
<div dir="ltr">
<div>
<div>
<div>
<div>
<div>
<div>
<div>Hello,<br>
<br>
</div>
I am confused to ask again, but could you help me
with this please ?<br>
</div>
I really don't know how to go further, if the behavior
I would like to have is supported by DRBD or not...<br>
<br>
</div>
DRBD team ?<br>
</div>
Any support would really be appreciated.<br>
<br>
</div>
Thank you again,<br>
<br>
</div>
Best regards,<br>
<br>
</div>
Ben<br>
<br>
<br>
<div>
<div>
<div>
<div>
<div>
<div>
<div>
<div>
<div>
<div class="gmail_extra"><br>
<div class="gmail_quote">2015-05-28 17:05
GMT+02:00 Ben RUBSON <span dir="ltr"><<a
moz-do-not-send="true"
href="mailto:ben.rubson@gmail.com"
target="_blank">ben.rubson@gmail.com</a>></span>:<br>
<blockquote class="gmail_quote"
style="margin:0 0 0 .8ex;border-left:1px
#ccc solid;padding-left:1ex">
<div dir="ltr">So,<br>
<br>
I played during hours with the dynamic
resync rate controller.<br>
Here are my settings :<br>
<br>
c-plan-ahead 10; //10ms between my 2
nodes, but minimum 1 second
recommended here : <a
moz-do-not-send="true"
href="https://blogs.linbit.com/p/128/drbd-sync-rate-controller/"
target="_blank">https://blogs.linbit.com/p/128/drbd-sync-rate-controller/</a><br>
resync-rate 680M; //mainly ignored<br>
c-min-rate 400M;<br>
c-max-rate 680M;<br>
c-fill-target 20M; //my BDP is 6.8M,
guides say to use a value between 1x
and 3x BDP<br>
<br>
Resync can achieve up to 680M when
there are no application IOs on the
source.<br>
However, as soon as there are
application IOs (writes with dd in my
tests), resync slows down to some
MB/s...<br>
I played with c-plan-ahead and
c-fill-target without success.<br>
I also tested c-delay-target.<br>
I tried to set unplug-watermark to 16.<br>
My IO scheduler is already the
deadline one...<br>
<br>
Well, I'm a little bit lost, I can't
achieve to get resync with a minimum
rate of 400M when there are
application IOs...<br>
<br>
Here, Lars says :<br>
<a moz-do-not-send="true"
href="http://lists.linbit.com/pipermail/drbd-user/2011-August/016739.html"
target="_blank">http://lists.linbit.com/pipermail/drbd-user/2011-August/016739.html</a><br>
The dynamic resync rate controller
basically tries to use as much as
c-max-rate bandwidth, but will
automatically throttle, if<br>
- application IO on the device is
detected (READ or WRITE), AND the
estimated current resync speed is
above c-min-rate<br>
- the amount of in-flight resync
requests exceeds c-fill-target<br>
<br>
However, does DRBD throttle
application IOs when resync rate is
lower than c-min-rate ?<br>
According to my tests I'm not so sure.<br>
<br>
<br>
<div>
<div class="h5">
<div class="gmail_extra"><br>
<div class="gmail_quote">2015-05-26
15:06 GMT+02:00 A.Rubio <span
dir="ltr"><<a
moz-do-not-send="true"
href="mailto:aurusa@etsii.upv.es"
target="_blank">aurusa@etsii.upv.es</a>></span>:<br>
<blockquote
class="gmail_quote"
style="margin:0 0 0
.8ex;border-left:1px #ccc
solid;padding-left:1ex">
<div bgcolor="#FFFFFF"
text="#000000"> Have you
test these values ?<br>
<br>
<a moz-do-not-send="true"
href="https://drbd.linbit.com/users-guide/s-throughput-tuning.html"
target="_blank">https://drbd.linbit.com/users-guide/s-throughput-tuning.html</a><br>
<br>
<br>
<div>El 26/05/15 a las
13:16, Ben RUBSON
escribió:<br>
</div>
<blockquote type="cite">
<div>
<div>
<div dir="ltr">
<div>RAID
controller is OK
yes.<br>
<br>
</div>
Here is a 4 steps
example of the
issue :<br>
<br>
<br>
<br>
### 1 - initial
state :<br>
<br>
Source :<br>
- sdb read
MB/s : 0<br>
- sdb write
MB/s : 0<br>
- eth1 incoming
MB/s : 0<br>
- eth1 outgoing
MB/s : 0<br>
Target :<br>
- sdb read
MB/s : 0<br>
- sdb write
MB/s : 0<br>
- eth1 incoming
MB/s : 0<br>
- eth1 outgoing
MB/s : 0<br>
<br>
<br>
<br>
### 2 - dd
if=/dev/zero
of=bigfile :<br>
<br>
Source :<br>
- sdb read
MB/s : 0<br>
- sdb write
MB/s : 670<br>
- eth1 incoming
MB/s : 1<br>
- eth1 outgoing
MB/s : 670<br>
Target :<br>
- sdb read
MB/s : 0<br>
- sdb write
MB/s : 670<br>
- eth1 incoming
MB/s : 670<br>
- eth1 outgoing
MB/s : 1<br>
<br>
<br>
<br>
### 3 - disable
the link between
the 2 nodes :<br>
<br>
Source :<br>
- sdb read
MB/s : 0<br>
- sdb write
MB/s : 670<br>
- eth1 incoming
MB/s : 0<br>
- eth1 outgoing
MB/s : 0<br>
Target :<br>
- sdb read
MB/s : 0<br>
- sdb write
MB/s : 0<br>
- eth1 incoming
MB/s : 0<br>
- eth1 outgoing
MB/s : 0<br>
<br>
<br>
<br>
### 4 - re-enable
the link between
the 2 nodes :<br>
<br>
Source :<br>
- sdb read
MB/s : ~20<br>
- sdb write
MB/s : ~670<br>
- eth1 incoming
MB/s : 1<br>
- eth1 outgoing
MB/s : 670<br>
Target :<br>
- sdb read
MB/s : 0<br>
- sdb write
MB/s : 670<br>
- eth1 incoming
MB/s : 670<br>
- eth1 outgoing
MB/s : 1<br>
DRBD resource :<br>
1: cs:SyncTarget
ro:Secondary/Primary
ds:Inconsistent/UpToDate
C r-----<br>
ns:62950732
nr:1143320132
dw:1206271712
dr:1379744185
al:9869 bm:6499
lo:2 pe:681 ua:1
ap:0 ep:1 wo:d
oos:11883000<br>
[>...................]
sync'ed: 6.9%
(11604/12448)M<br>
finish:
0:34:22 speed:
5,756 (6,568)
want: 696,320
K/sec<br>
<br>
<br>
<br>
### values I would
have expected in
step 4 :<br>
<br>
Source :<br>
- sdb read
MB/s : ~400
(because of
c-min-rate 400M)<br>
- sdb write
MB/s : ~370<br>
- eth1 incoming
MB/s : 1<br>
- eth1 outgoing
MB/s : 670<br>
Target :<br>
- sdb read
MB/s : 0<br>
- sdb write
MB/s : 670<br>
- eth1 incoming
MB/s : 670<br>
- eth1 outgoing
MB/s : 1<br>
<div>
<div>
<div
class="gmail_extra"><br>
</div>
<div
class="gmail_extra">Why
resync is
totally
ignored and
application
(dd here in
the example)
still consumes
all available
IOs /
bandwidth ?<br>
<br>
<br>
<br>
<div
class="gmail_quote">2015-05-25
16:50
GMT+02:00
A.Rubio <span
dir="ltr"><<a
moz-do-not-send="true" href="mailto:aurusa@etsii.upv.es" target="_blank">aurusa@etsii.upv.es</a>></span>:<br>
<blockquote
class="gmail_quote"
style="margin:0px
0px 0px
0.8ex;border-left:1px
solid
rgb(204,204,204);padding-left:1ex">Cache
settings an
I/O in RAID
controller is
optimal ???
Write-back,
write-through,
cache enablad,
I/O direct,
...<br>
<br>
El 25/05/15 a
las 11:50, Ben
RUBSON
escribió:<br>
<blockquote
class="gmail_quote"
style="margin:0px
0px 0px
0.8ex;border-left:1px
solid
rgb(204,204,204);padding-left:1ex">
<div>
<div> The link
between nodes
is a 10Gb/s
link.<br>
The DRBD
resource is a
RAID-10 array
which is able
to resync at
up to 800M (as
you can see I
have lowered
it to 680M in
my
configuration
file).<br>
<br>
The "issue"
here seems to
be a
prioritization
"issue"
between
application
IOs and resync
IOs.<br>
Perhaps I
miss-configured
something ?<br>
Goal is to
have resync
rate up to
680M, with a
minimum of
400M, even if
there are
application
IOs.<br>
This in order
to be sure to
complete the
resync even if
there are a
lot of write
IOs from the
application.<br>
<br>
With my simple
test below,
this is not
the case, dd
still writes
at its best
throughput,
lowering
resync rate
which can’t
reach 400M at
all.<br>
<br>
Thank you !<br>
<br>
<blockquote
class="gmail_quote"
style="margin:0px
0px 0px
0.8ex;border-left:1px
solid
rgb(204,204,204);padding-left:1ex">
Le 25 mai 2015
à 11:18,
A.Rubio <<a
moz-do-not-send="true" href="mailto:aurusa@etsii.upv.es" target="_blank">aurusa@etsii.upv.es</a>>
a écrit :<br>
<br>
the link
between nodes
is ??? 1Gb/s
??? , 10Gb/s
??? ...<br>
<br>
the Hard Disks
are ??? SATA
7200rpm ???,
10000rpm ???,
SAS ???,<br>
SSD ???...<br>
<br>
400M to 680M
with a 10Gb/s
link and SAS
15.000 rpm is
OK but less
...<br>
<br>
<blockquote
class="gmail_quote"
style="margin:0px
0px 0px
0.8ex;border-left:1px
solid
rgb(204,204,204);padding-left:1ex">
Le 12 avr.
2014 à 17:23,
Ben RUBSON
<<a
moz-do-not-send="true"
href="mailto:ben.rubson@gmail.com" target="_blank">ben.rubson@gmail.com</a>>
a écrit :<br>
<br>
Hello,<br>
<br>
Let's assume
the following
configuration
:<br>
disk {<br>
c-plan-ahead
0;<br>
resync-rate
680M;<br>
c-min-rate
400M;<br>
}<br>
<br>
Both nodes are
uptodate, and
on the
primary, I
have a test IO
burst running,
using dd.<br>
<br>
I then cut
replication
link for a few
minutes so
that secondary
node will be
several GB
behind primary
node.<br>
<br>
I then
re-enable
replication
link.<br>
What I expect
here according
to the
configuration
is that
secondary node
will fetch
missing GB at
a 400 MB/s
throughput.<br>
DRBD should
then prefer
resync IOs
over
application
(dd here) IOs.<br>
<br>
However, it
does not seems
to work.<br>
dd still
writes at its
best
throughput,
meanwhile
reads are made
from the
primary disk
between 30 and
60 MB/s to
complete the
resync.<br>
Of course this
is not the
expected
behaviour.<br>
<br>
Did I miss
something ?</blockquote>
</blockquote>
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