[Drbd-dev] SCTP support for drbd

[Drbd-dev] SCTP support for drbd

[Lars Marowsky-Bree]

Hi all,

Florian asked me to post this to the list.

As you know, OpenAIS/corosync supports, similar to but slightly more
broken than heartbeat, redundant rings to provide redundant networking.

On SLE HA 11 GA, we recommended that customers not use this, but instead
use bonded NICs. This was not just because of the limitations in
OpenAIS, but also because of the limitations of the services we consider
essential.

The DLM, for example, was not able to take automatic advantage of the
redundant links - SCTP support was a bit flakey then. This is changed
(the kernel DLM already supports SCTP, and the patch for automatic
enablement in libdlm is bound to be done in a few days).

The other service is drbd, which also uses TCP-only right now. It'd be
nice if it also supported SCTP; it can't be that hard, since the
in-kernel dlm also supports TCP and SCTP.


As a further consideration, I'd like to point out how cool it'd be if
drbd could also, like the DLM, default to gathering its network
information from the OpenAIS/corosync layer (perhaps via a
drbd_controld); the peers could auto-detect each other based on the
UUID/label of the drbd instance being activated.  It'd reduce the need
to duplicate information between configuration files for the most common
scenarios.

(This would also be an extremely convenient and even neater way for
floating peers.)


Regards,
    Lars

-- 
Architect Storage/HA, OPS Engineering, Novell, Inc.
SUSE LINUX Products GmbH, GF: Markus Rex, HRB 16746 (AG Nürnberg)
"Experience is the name everyone gives to their mistakes." -- Oscar Wilde

Re: [Drbd-dev] SCTP support for drbd

[Lars Ellenberg]

On Fri, Oct 16, 2009 at 12:38:45PM +0200, Lars Marowsky-Bree wrote:
> Hi all,
> 
> Florian asked me to post this to the list.
> 
> As you know, OpenAIS/corosync supports, similar to but slightly more
> broken than heartbeat, redundant rings to provide redundant networking.
> 
> On SLE HA 11 GA, we recommended that customers not use this, but instead
> use bonded NICs. This was not just because of the limitations in
> OpenAIS, but also because of the limitations of the services we consider
> essential.
> 
> The DLM, for example, was not able to take automatic advantage of the
> redundant links - SCTP support was a bit flakey then. This is changed
> (the kernel DLM already supports SCTP, and the patch for automatic
> enablement in libdlm is bound to be done in a few days).
> 
> The other service is drbd, which also uses TCP-only right now. It'd be
> nice if it also supported SCTP; it can't be that hard, since the
> in-kernel dlm also supports TCP and SCTP.

Is somewhere on our todo list,
but may have to wait for DRBD 9.
Feature sponsoring accepted ;)

> As a further consideration, I'd like to point out how cool it'd be if
> drbd could also, like the DLM, default to gathering its network
> information from the OpenAIS/corosync layer (perhaps via a
> drbd_controld); the peers could auto-detect each other based on the
> UUID/label of the drbd instance being activated.  It'd reduce the need
> to duplicate information between configuration files for the most common
> scenarios.
>
> (This would also be an extremely convenient and even neater way for
> floating peers.)

-EPONIES

proof of concept implementations may be reviewed, though ;)

-- 
: Lars Ellenberg
: LINBIT | Your Way to High Availability
: DRBD/HA support and consulting http://www.linbit.com

DRBD® and LINBIT® are registered trademarks of LINBIT, Austria.

Re: [Drbd-dev] SCTP support for drbd

[Lars Marowsky-Bree]

On 2009-10-16T13:20:01, Lars Ellenberg <lars.ellenberg@linbit.com> wrote:

> > The other service is drbd, which also uses TCP-only right now. It'd be
> > nice if it also supported SCTP; it can't be that hard, since the
> > in-kernel dlm also supports TCP and SCTP.
> Is somewhere on our todo list,
> but may have to wait for DRBD 9.
> Feature sponsoring accepted ;)

How much sponsoring do you need? Florian said it looked trivial enough.
;-)

> > As a further consideration, I'd like to point out how cool it'd be if
> > drbd could also, like the DLM, default to gathering its network
> > information from the OpenAIS/corosync layer (perhaps via a
> > drbd_controld); the peers could auto-detect each other based on the
> > UUID/label of the drbd instance being activated.  It'd reduce the need
> > to duplicate information between configuration files for the most common
> > scenarios.
> >
> > (This would also be an extremely convenient and even neater way for
> > floating peers.)
> -EPONIES

It may be something you could put on said todo list as well. It'd be
beneficial for drbd users, would it not?

> proof of concept implementations may be reviewed, though ;)

Well, before heading down that path it may be worthwhile to get feedback
as to whether you think this is a useful feature or not. Even if we
don't implement it, maybe one day there'll be a student looking for a
thesis topic ;-)



Regards,
    Lars

-- 
Architect Storage/HA, OPS Engineering, Novell, Inc.
SUSE LINUX Products GmbH, GF: Markus Rex, HRB 16746 (AG Nürnberg)
"Experience is the name everyone gives to their mistakes." -- Oscar Wilde

Re: [Drbd-dev] SCTP support for drbd

[Florian Haas]

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On 10/16/2009 01:43 PM, Lars Marowsky-Bree wrote:
> On 2009-10-16T13:20:01, Lars Ellenberg <lars.ellenberg@linbit.com> wrote:
> 
>>> The other service is drbd, which also uses TCP-only right now. It'd be
>>> nice if it also supported SCTP; it can't be that hard, since the
>>> in-kernel dlm also supports TCP and SCTP.
>> Is somewhere on our todo list,
>> but may have to wait for DRBD 9.
>> Feature sponsoring accepted ;)
> 
> How much sponsoring do you need? Florian said it looked trivial enough.
> ;-)

Talk about a quote yanked out of context. I dug up one code snippet and
said "looks good". No word about trivial, as far as I remember.

Florian


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