Mailing List Archive: DRBD: Users

Sync speed (getting to the limit)

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marcelops at gmail

Apr 5, 2012, 5:58 PM

Post #1 of 5 (582 views)
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Sync speed (getting to the limit)

Hi DRBD masters,

I have been trying to push the sync speed to the limit, as the server was
offline for a while and I will release it for general use only after it's
sync'ed. So, nobody is using and I can use full speed.

I have two servers, each one connected to a NAS unit through a CAT6 cable,
no switches in between. It's 1000 Mpbs full duplex, as the ethtool says.

I tried to push to the limit, issuing the following:

[~]# /sbin/drbdsetup /dev/drbd0 syncer -r 685M

I can't go beyond 685M, as it says it's not a valid parameter (from 686 and
beyond).

And then the /proc/drbd looks like it:

*node0: Primary*

version: 8.3.12 (api:88/proto:86-96)
GIT-hash: e2a8ef4656be026bbae540305fcb998a5991090f build by
mockbuild [at] builder10, 2012-01-28 13:52:25
0: cs:SyncSource ro:Primary/Secondary ds:UpToDate/Inconsistent C r-----
ns:576775776 nr:0 dw:108 dr:576798277 al:3 bm:166274 lo:26 pe:57 ua:64
ap:0 ep:1 wo:b oos:4171057976
[>....................] sync'ed: 0.9% (4073296/4106360)M
finish: 16:14:21 speed: 71,340 (64,984) K/sec

*node1: Secondary*

version: 8.3.12 (api:88/proto:86-96)
GIT-hash: e2a8ef4656be026bbae540305fcb998a5991090f build by
mockbuild [at] builder10, 2012-01-28 13:52:40
0: cs:SyncTarget ro:Secondary/Primary ds:Inconsistent/UpToDate C r-----
ns:0 nr:33272320 dw:33272320 dr:0 al:0 bm:2031 lo:1 pe:7421 ua:0 ap:0
ep:1 wo:b oos:4171642808
[>....................] sync'ed: 0.8% (4073868/4106360)M
finish: 16:13:46 speed: 71,384 (64,856) want: 701,440 K/sec

At this point, it is going dramatically fast, as the original configuration
(10M) was forecasting 190 hours to sync... (16h, in this case, is a charm).
How can I know if it's the faster it can go???

Thanks,
Marcelo

brian at linbit

Apr 5, 2012, 6:10 PM

Post #2 of 5 (537 views)
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Re: Sync speed (getting to the limit) [In reply to]

On 04/05/2012 05:58 PM, Marcelo Pereira wrote:
> Hi DRBD masters,
>
> I have been trying to push the sync speed to the limit, as the server
> was offline for a while and I will release it for general use only
> after it's sync'ed. So, nobody is using and I can use full speed.
>
> I have two servers, each one connected to a NAS unit through a CAT6
> cable, no switches in between. It's 1000 Mpbs full duplex, as the
> ethtool says.
>
> I tried to push to the limit, issuing the following:
>
> [~]# /sbin/drbdsetup /dev/drbd0 syncer -r 685M
Please note that this rate is in MB/sec not Mb/s, ideally you should set
it around 80% of your connection speed. On 1Gbe the max is around
120MB/sec, but in reality, due to overhead, you won't get that.
>
> I can't go beyond 685M, as it says it's not a valid parameter (from
> 686 and beyond).At this point, it is going dramatically fast, as the
> original configuration (10M) was forecasting 190 hours to sync...
> (16h, in this case, is a charm). How can I know if it's the faster it
> can go???
Check iperf to get the base speed of your ethernet controllers, then
check to see how fast your storage can go. Whatever is slower will be
your bottleneck, tune from there.

Check here for further details.
http://www.drbd.org/users-guide/p-performance.html

Best regards,
Brian

--

: Brian Hellman
: LINBIT | "Your Way to High Availability"
: 1-503-573-1262 x202 | 1-877-4-LINBIT
: Web: http://www.linbit.com
:
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florian at hastexo

Apr 6, 2012, 12:33 AM

Post #3 of 5 (537 views)
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Re: Sync speed (getting to the limit) [In reply to]

On Fri, Apr 6, 2012 at 3:10 AM, Brian R. Hellman <brian [at] linbit> wrote:
>
>
> On 04/05/2012 05:58 PM, Marcelo Pereira wrote:
>> Hi DRBD masters,
>>
>> I have been trying to push the sync speed to the limit, as the server
>> was offline for a while and I will release it for general use only
>> after it's sync'ed. So, nobody is using and I can use full speed.
>>
>> I have two servers, each one connected to a NAS unit through a CAT6
>> cable, no switches in between. It's 1000 Mpbs full duplex, as the
>> ethtool says.
>>
>> I tried to push to the limit, issuing the following:
>>
>> [~]# /sbin/drbdsetup /dev/drbd0 syncer -r 685M
> Please note that this rate is in MB/sec not Mb/s, ideally you should set
> it around 80% of your connection speed.

Did the 30% recommendation change (for statically defined sync rates),
and if it did, when and why?
http://www.drbd.org/users-guide/s-configure-sync-rate.html does still
mention it.

Cheers
Florian

--
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ediazrod at gmail

Apr 9, 2012, 7:27 AM

Post #4 of 5 (510 views)
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Re: Sync speed (getting to the limit) [In reply to]

Don't use a direct connexion, I have many problems for this in the pass...
Is better buy a good switch (netgear has por 35€)...

On Fri, Apr 6, 2012 at 9:33 AM, Florian Haas <florian [at] hastexo> wrote:

> On Fri, Apr 6, 2012 at 3:10 AM, Brian R. Hellman <brian [at] linbit> wrote:
> >
> >
> > On 04/05/2012 05:58 PM, Marcelo Pereira wrote:
> >> Hi DRBD masters,
> >>
> >> I have been trying to push the sync speed to the limit, as the server
> >> was offline for a while and I will release it for general use only
> >> after it's sync'ed. So, nobody is using and I can use full speed.
> >>
> >> I have two servers, each one connected to a NAS unit through a CAT6
> >> cable, no switches in between. It's 1000 Mpbs full duplex, as the
> >> ethtool says.
> >>
> >> I tried to push to the limit, issuing the following:
> >>
> >> [~]# /sbin/drbdsetup /dev/drbd0 syncer -r 685M
> > Please note that this rate is in MB/sec not Mb/s, ideally you should set
> > it around 80% of your connection speed.
>
> Did the 30% recommendation change (for statically defined sync rates),
> and if it did, when and why?
> http://www.drbd.org/users-guide/s-configure-sync-rate.html does still
> mention it.
>
> Cheers
> Florian
>
> --
> Need help with High Availability?
> http://www.hastexo.com/now
> _______________________________________________
> drbd-user mailing list
> drbd-user [at] lists
> http://lists.linbit.com/mailman/listinfo/drbd-user
>

marcelops at gmail

Apr 9, 2012, 7:30 AM

Post #5 of 5 (508 views)
Permalink

Re: Sync speed (getting to the limit) [In reply to]

Hello,

I definitely agree on using a good switch (which I have already bought).

However, as I had a very weird problem with the switch and I couldn't
figure the problem out, I just removed it from the play, connecting a
direct cable, and it's working perfectly now.

I will add the new switch to the rack in a couple of days and restore the
scenario it is supposed to be, but it's working perfectly now, with the
direct (crossover) cable. What was exactly your problem in the past????

Thanks,
Marcelo

On Mon, Apr 9, 2012 at 10:27 AM, Eduardo Diaz - Gmail <ediazrod [at] gmail>wrote:

> Don't use a direct connexion, I have many problems for this in the pass...
> Is better buy a good switch (netgear has por 35�)...
>
>
> On Fri, Apr 6, 2012 at 9:33 AM, Florian Haas <florian [at] hastexo> wrote:
>
>> On Fri, Apr 6, 2012 at 3:10 AM, Brian R. Hellman <brian [at] linbit>
>> wrote:
>> >
>> >
>> > On 04/05/2012 05:58 PM, Marcelo Pereira wrote:
>> >> Hi DRBD masters,
>> >>
>> >> I have been trying to push the sync speed to the limit, as the server
>> >> was offline for a while and I will release it for general use only
>> >> after it's sync'ed. So, nobody is using and I can use full speed.
>> >>
>> >> I have two servers, each one connected to a NAS unit through a CAT6
>> >> cable, no switches in between. It's 1000 Mpbs full duplex, as the
>> >> ethtool says.
>> >>
>> >> I tried to push to the limit, issuing the following:
>> >>
>> >> [~]# /sbin/drbdsetup /dev/drbd0 syncer -r 685M
>> > Please note that this rate is in MB/sec not Mb/s, ideally you should set
>> > it around 80% of your connection speed.
>>
>> Did the 30% recommendation change (for statically defined sync rates),
>> and if it did, when and why?
>> http://www.drbd.org/users-guide/s-configure-sync-rate.html does still
>> mention it.
>>
>> Cheers
>> Florian
>>
>> --
>> Need help with High Availability?
>> http://www.hastexo.com/now
>> _______________________________________________
>> drbd-user mailing list
>> drbd-user [at] lists
>> http://lists.linbit.com/mailman/listinfo/drbd-user
>>
>
>
> _______________________________________________
> drbd-user mailing list
> drbd-user [at] lists
> http://lists.linbit.com/mailman/listinfo/drbd-user
>
>

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