Hi Florian,
Thanks again for all of your help.
While the diagram makes clear the entire flow of the process, I am
looking for something like a flow chart to depict the order of
operations. For instance, what is the flow of the data and order of
operations when a write occurs to /dev/drbd0 on the primary and how is
it applied on the other node- a write occurs to /dev/drbd0 on node1, it
writes to the real block device on node1, then is put on the socket to
node2, node2 receives data and applies algo check (if applied), data
written to /dev/drbd0 on node2.
The fundamentals page also only gives a brief overview of how it works
at a high level, I am looking to see what actually occurs under the hood
so perhaps I should start looking at the kernel docs that you pointed
out earlier?
Regards,
Chuck Kozler
/Lead Infrastructure & Systems Administrator/
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On 10/14/2011 5:21 AM, Charles Kozler wrote:
Haven't read it yet though I will later today.
Having not ready any of the documentation of the underlying processes/workings,
all of my understandings were purely based on assumptions from my basic use
with DRBD- that said, thank you for all your insight and I will let you know
later my understandings :)
Sent from my Verizon Wireless BlackBerry
-----Original Message-----
From: Florian Haas<[email protected]>
Sender: [email protected]
Date: Fri, 14 Oct 2011 09:08:17
To:<[email protected]>
Subject: Re: [DRBD-user] Disk Corruption = DRBD Failure?
On 2011-10-12 20:30, Charles Kozler wrote:
I will re-read the DRBD Funadmentals- the way I understood it was
basically if you were writing to node1 it wouldn't put the data through
a TCP socket and would actually just write directly to the block device
and that TCP was usually only used for the actual replicating and data
integrity conversation between the hosts. My understanding now is that
for all hosts included in the resource definition it will put the data
into that socket - including the host you're writing from (eg: if I
wrote to /dev/drbd0 on host1 it will go through the socket to write the
data still to write it to the underlying block device-
Er, no. It won't.
I had originally
thought it would skip the TCP socket write and write directly to the
block device).
For the _local_ write, of course it doesn't go through the TCP socket.
Why should it? That would be braindead. Also, given the documentation,
what makes you think so? I ask because I wrote it, and if there's
anything horribly unclear in there I'd be happy to fix it.
Did you look at the illustration in the Fundamentals chapter?
Florian
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