[DRBD-user] Concurrent writes

Roof, Morey R. MRoof at admin.nmt.edu
Tue Apr 21 23:39:36 CEST 2009

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


The Initiators I use are: VMWare ESX 3.0.x, VMWare ESX 3.5.x, Micrsoft
iSCSI Initiator 2.08, and Linux (RHEL 5, SUSE 10).
 
I gave SQLIO a run with your params and I'm not getting the concurrent
write issue.

The hardware I run DRBD is a pair of HP Proliant DL380 G4 servers with
12GB of RAM and P600 SAS controllers.  The machines are currently
replicating 1.8TB of data.  I run DRBD under SuSE 10SP2 and use IET
stock from SuSE but the DRBD is 8.0.16.
 
 
-
Morey Roof
Information Services Department
New Mexico Institute of Mining and Technology



________________________________

From: drbd-user-bounces at lists.linbit.com
[mailto:drbd-user-bounces at lists.linbit.com] On Behalf Of Gennadiy
Nerubayev
Sent: Tuesday, April 21, 2009 3:18 PM
To: drbd-user at lists.linbit.com
Subject: Re: [DRBD-user] Concurrent writes


On Tue, Apr 21, 2009 at 2:47 PM, Roof, Morey R. <MRoof at admin.nmt.edu>
wrote:


	This is a really interesting discussion.  I use DRBD to
replicate
	volumes that are exported via blockio with IET and have never
gotten
	this message.  I currently use DRBD 8.0.16 and over the last
year with
	8.0.x series this message has never appeared.  Before deployment
all
	sorts of io tests were conducted and this message wasn't present
then
	either.


Thanks for the input. What are the initiators that you're using? 



	So, I have an idea of a setting for you to change on your iSCSI
target
	system and I'm really curious if the message goes away.  In IET
we have
	"InitialR2T Yes" but the default is "No".  Trying running that
way and
	see what happens as I'm very curious about the results.
	


Just tried "InitialR2T Yes", and there was no effect; the concurrent
write warnings are still being generated.

As a side note for anyone who would like to test this, on windows in
particular, here's one of tools I use to duplicate this:

SQLIO:
http://www.microsoft.com/downloads/details.aspx?familyid=9a8b005b-84e4-4
f24-8d65-cb53442d9e19&displaylang=en
Contents of param.txt (this assumes f: is the remote storage, and you
have one gb free space available): f:\testfile.dat 4 0x0 1024
Command to run: sqlio -kW -s60 -frandom -o8 -b8 -LS -Fparam.txt

-Gennadiy




More information about the drbd-user mailing list