[DRBD-user] rate limit is 700M?

Stephan Rattai srattai at zmnh.uni-hamburg.de
Tue Feb 14 16:20:50 CET 2006

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.


Am Dienstag, 14. Februar 2006 15:30 schrieb Saul, Markus:
> -----Ursprüngliche Nachricht-----
>
> >Von: drbd-user-bounces at lists.linbit.com
> > [mailto:drbd-user-bounces at lists.linbit.com] Im Auftrag von Stephan Rattai
> > Gesendet: Dienstag, 14. Februar 2006 13:56
> >An: drbd-user at linbit.com
> >Betreff: Re: [DRBD-user] rate limit is 700M?
> >
> >Sure, 250 M is nonsense, I was just was just thinking about a 2 Gb fc
> >interface I've been messing around with. Dividing 2000 by 8 is not quite
> >correct, just a bad habit. Anyway this seems not as important to me as
> > these are values I've never seen in reality.
>
> Well, I think it's important (at least to myself) not to loose the overview
> of the used units. Especially in the area of bits and bytes, since they are
> mostly loosely used. Not only in the verbal but also the written language.
>
> And I stepped myself into the trap:

Me, too, considering that as far as I know according to IEC 60027-2 'G'(b) 
stands for 'Giga'(bit) and as such for 10^9 thus dividing 2000 by 8 leading 
to 250 would be correct for 2Gb. Opposed to 2Gib. One could discuss about M 
vs. Mi and their friends for quite a while and I think when it comes to 
Petabytes vs. Pebibytes in terms of capacity there is quite a remarkable 
difference but in terms of Gbit NIC I don't think of it as important. Also I 
haven't heard anyone using kibi and the likes before. 

But I really do not need to discuss about this. 

However I still don't know why drbd offers the 'G' as suffix although the 
limit seems to be 700000K....Byte.

> I wrote
>
> >If the unit is meant to be MBytes/s (or MiBytes),... it would mean that
> > the base is 2, this gives you speeds of  2^x like 1024 MBytes/s, this
> > divided by 8 gives 128M.
>
> This is just wrong in this case, because the speed of the network link is 1
> Gbit/s so it is 1024 Mbit/s  with the base of 2.  So just replace the
> MByte/MiByte With MBit in above paragraph. With a base of 10 it would be
> 1000 mbit/s and 125M as setting for drbd.

So you are using lowercase for powers of 10 and uppercase M for powers of 2 ? 
Is this official ? Wouldn't it have to be 125mbit/s for drbd instead of 
125Mbit ? I'd rather stick to this one:
http://physics.nist.gov/cuu/Units/binary.html

Haven't seen an iso on this topic so far.

By the way- isn't 'ko' used in french for 'kilo octets' ? What would a 
Gibibyte be in french ? A Gio ? This is getting a bit confusing...

If my part of this mail consists of total crap just forget it- now I'm 
confused !
>
>
>
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