* [Lustre-devel] IPv6 NIDs
2011-10-11 13:20 [Lustre-devel] IPv6 NIDs Eric Barton
@ 2011-10-11 13:34 ` chas williams - CONTRACTOR
2011-10-11 17:26 ` Nathan Rutman
2011-10-12 6:18 ` Isaac Huang
2 siblings, 0 replies; 4+ messages in thread
From: chas williams - CONTRACTOR @ 2011-10-11 13:34 UTC (permalink / raw)
To: lustre-devel
On Tue, 11 Oct 2011 14:20:44 +0100
"Eric Barton" <eeb@whamcloud.com> wrote:
> 2. Hedge a little by reserving an additional (say) 32 bits for
> something we've not thought of yet and keeping the total a
> multiple of 64 bits to simplify alignment.
> 192 bits / 24 bytes total.
>
> 3. Hedge a lot with a nice round number.
> 256 bits / 32 bytes total.
i would pick this. you never know what address size is coming in the
future for any particular protocol. the infiniband link layer is
160 bits. so if someone implemented a 'native' ib solution they
would need 160 + 32 (192).
of course, option 2 would work fine in this case. however, unless there
is a pressing reason i would just pick 256 because we already have a
case that could use up your 'hedge a little'.
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Lustre-devel] IPv6 NIDs
2011-10-11 13:20 [Lustre-devel] IPv6 NIDs Eric Barton
2011-10-11 13:34 ` chas williams - CONTRACTOR
@ 2011-10-11 17:26 ` Nathan Rutman
2011-10-12 6:18 ` Isaac Huang
2 siblings, 0 replies; 4+ messages in thread
From: Nathan Rutman @ 2011-10-11 17:26 UTC (permalink / raw)
To: lustre-devel
On Oct 11, 2011, at 6:20 AM, Eric Barton wrote:
> I'd like to canvass thoughts on how big an IPv6 compatible NID
> might be. We'd like to start anticipating changing to these NIDs
> so that current development at least doesn't dig us deeper into a
> hole (e.g. on the nidtable entries sent over the wire in
> imperative recovery). So here are some suggestions....
>
> Current NID: 32 bit address-within LNET + 32 bit LNET number
> 64 bits / 8 bytes total
>
> IPv6 compatible NID:
>
> 1. Minimum: 128 bit address-within-LNET + 32 bit LNET number.
> 160 bits / 20 bytes total.
>
> 2. Hedge a little by reserving an additional (say) 32 bits for
> something we've not thought of yet and keeping the total a
> multiple of 64 bits to simplify alignment.
> 192 bits / 24 bytes total.
>
> 3. Hedge a lot with a nice round number.
> 256 bits / 32 bytes total.
>
> (2) gets my vote currently...
The cost of the bytes is so minor compared to the cost of revving the protocol, I vote for 3.
BTW, Isaac is starting to look in to how much work it would be to rev the protocol for full
IPv6 interoperability.=
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^ permalink raw reply [flat|nested] 4+ messages in thread
* [Lustre-devel] IPv6 NIDs
2011-10-11 13:20 [Lustre-devel] IPv6 NIDs Eric Barton
2011-10-11 13:34 ` chas williams - CONTRACTOR
2011-10-11 17:26 ` Nathan Rutman
@ 2011-10-12 6:18 ` Isaac Huang
2 siblings, 0 replies; 4+ messages in thread
From: Isaac Huang @ 2011-10-12 6:18 UTC (permalink / raw)
To: lustre-devel
On Tue, Oct 11, 2011 at 02:20:44PM +0100, Eric Barton wrote:
> ......
> IPv6 compatible NID:
>
> 1. Minimum: 128 bit address-within-LNET + 32 bit LNET number.
> 160 bits / 20 bytes total.
(1) might cause alignment problem somewhere. I remember that the
PTLLND is picky on alignments, and there might be more such places.
> 2. Hedge a little by reserving an additional (say) 32 bits for
> something we've not thought of yet and keeping the total a
> multiple of 64 bits to simplify alignment.
> 192 bits / 24 bytes total.
>
> 3. Hedge a lot with a nice round number.
> 256 bits / 32 bytes total.
>
> (2) gets my vote currently...
I'd feel happy to pay the extra 8 bytes for the peace of mind that I
wouldn't have to handle this again.
- Isaac
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Internet email is susceptible to data corruption, interception and unauthorised amendment for which Xyratex does not accept liability. While we have taken reasonable precautions to ensure that this email is free of viruses, Xyratex does not accept liability for the presence of any computer viruses in this email, nor for any losses caused as a result of viruses.
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The Xyratex group of companies also includes, Xyratex Ltd, registered in Bermuda, Xyratex International Inc, registered in California, Xyratex (Malaysia) Sdn Bhd registered in Malaysia, Xyratex Technology (Wuxi) Co Ltd registered in The People's Republic of China and Xyratex Japan Limited registered in Japan.
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^ permalink raw reply [flat|nested] 4+ messages in thread