[DRBD-user] Initializing shortcut

Martin Fick mogulguy at yahoo.com
Wed May 10 19:13:31 CEST 2006

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

--- Lars Ellenberg <Lars.Ellenberg at linbit.com> wrote:

> / 2006-05-10 09:39:12 -0700
> \ Carson Gaspar:
> > --On Wednesday, May 10, 2006 6:32 PM +0200 Lars
> Ellenberg <Lars.Ellenberg at linbit.com> wrote:
> > 
> > >but then again, once we implement the online
> > >verification, we would _need_ to have this
> initial
> > >sync, because the drives _have_ to be bitwise
> identical
> > >(that's one of our "guarantees", after all).
> > 
> > Actually, no - you don't have to do a network
> sync.
> > You can just write zeros on both sides.
> Oh? That's news! Tell me more :)
> if someone wants to do that, he can of course do
> that.  thats maybe
> usefull if you have smallish, fast storage but
> slowish network.

Well, large storage, but slow net, nevertheless not an
enterprise situation for me, these are my home pcs,
one is a 400MHz pentium with a 10baseT!

But I don't see how the size matters, only the
relative speed of your disk writes to your network
connection.  A larger disk means not just more
zeroing, but more syncing too! The zeroing solution
would still win and by more when things get bigger.

Don't forget that most people try several
onfigurations before they end up with their final
setup.  This is where saving time could be very
valuable.  Some people may even dish the whole product
just because it takes too long to setup in a new

First I needed to figure out how drbd worked, it took
me 4 hours to sync my 5G partition (*1).  I plan on
having a larger partition, but I thought that I would
test things with a small 5G partition first to see if
I understood how drbd worked.

*1: There very well could be something wrong with my
setup, I noticed that for the first hour throuput was
about 600KB/s but that after that it dropped to about
300KB/s and the last hour it was in the

> I think typically you rather have largish raid5
> backend,
> and a dedicated GigE link.
> Bottleneck is the storage box.  so what.

Maybe that is what it was intially designed for (but
maybe not, companies with money would just buy shared
storage!)  I would not dismiss the idea that simple
home users want high availability too.  Computers are
becoming a very important part of mine and other's
home lives too.  

While I would not suggest sacrificing capabilities on
the enterprise end, I believe that a product won't
truly be enterprise ready unless it can be effectively
used by the masses also... more users, more testing. 
This kind of speedup would make joe home hacker much
more likely to try drbd out and do weird stuff and
possibly expose new corner cases where drbd could use

> Nothing of this is likely to appear in drbd 0.7,
> though.

Fair enough. :)


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