WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-users

RE: [Xen-users] Re: Xen, LVM, DRBD, Linux-HA

To: "Steve Wray" <steve.wray@xxxxxxxxx>, <xen-users@xxxxxxxxxxxxxxxxxxx>
Subject: RE: [Xen-users] Re: Xen, LVM, DRBD, Linux-HA
From: "Ross S. W. Walker" <rwalker@xxxxxxxxxxxxx>
Date: Tue, 22 Apr 2008 16:27:49 -0400
Delivery-date: Tue, 22 Apr 2008 13:28:33 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxx
Importance: normal
In-reply-to: <480E4847.2020902@xxxxxxxxx>
List-help: <mailto:xen-users-request@lists.xensource.com?subject=help>
List-id: Xen user discussion <xen-users.lists.xensource.com>
List-post: <mailto:xen-users@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-users>, <mailto:xen-users-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-users>, <mailto:xen-users-request@lists.xensource.com?subject=unsubscribe>
Priority: normal
References: <20080421222832.GW26447@xxxxxxxxxxxxxxxxxxxxxxx> <fukbc1$ut0$1@xxxxxxxxxxxxx><480DB90C.4010202@xxxxxxxxx> <m3skxdubfw.fsf@xxxxxxxxxxxxxxxxxxx> <480E4847.2020902@xxxxxxxxx>
Sender: xen-users-bounces@xxxxxxxxxxxxxxxxxxx
Thread-index: AciktkLEFEBtF+KXQ+WtcLQ/ecbMswAADc3g
Thread-topic: [Xen-users] Re: Xen, LVM, DRBD, Linux-HA
Please do not hijack threads, please put all your drbd questions
to the drbd-user list.

If properly setup and maintained drbd should work properly.

-Ross
 

> -----Original Message-----
> From: xen-users-bounces@xxxxxxxxxxxxxxxxxxx 
> [mailto:xen-users-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of Steve Wray
> Sent: Tuesday, April 22, 2008 4:19 PM
> To: xen-users@xxxxxxxxxxxxxxxxxxx
> Subject: Re: [Xen-users] Re: Xen, LVM, DRBD, Linux-HA
> 
> I am going to reply to this thread but I'm going to start 
> from something 
> new as it doesn't seem to be covered in this thread so far.
> 
> I have been testing drbd under Xen and found some very 
> disturbing things.
> 
> I'd like to implement this in a production system but this scares the 
> hell out of me...
> 
> I have two Dom0 servers connected with a crossover cable between two 
> gigabit e1000 NICs. No switch involved.
> 
> One DomU on each server with a 20G drbd device shared between them.
> 
> 
> The drbd config contains:
> 
>    syncer {
>      rate 10M;
>      group 1;
>      al-extents 257;
>    }
> 
>    net {
>      on-disconnect reconnect;
>    }
> 
> 
> so the net section is working at defaults. At first I had 
> thought that 
> the problems I was seeing was due to timeout values etc and tried 
> various parameters in the net section but nothing made any difference.
> 
> When, on the current secondary node, I execute
> 
> drbdadm invalidate all
> 
> I get frequent errors such as:
> 
> drbd0: PingAck did not arrive in time.
> drbd0: drbd0_asender [1572]: cstate SyncSource --> NetworkFailure
> drbd0: asender terminated
> drbd0: drbd_send_block() failed
> drbd0: drbd0_receiver [1562]: cstate NetworkFailure --> BrokenPipe
> drbd0: short read expecting header on sock: r=-512
> drbd0: worker terminated
> drbd0: ASSERT( mdev->ee_in_use == 0 ) in 
> /usr/src/modules/drbd/drbd/drbd_receiver.c:1880
> drbd0: drbd0_receiver [1562]: cstate BrokenPipe --> Unconnected
> drbd0: Connection lost.
> 
> 
> I observe the xm top in both Dom0's and I note a HUGE amount 
> of dropped 
> RX packets being reported on both DomU's vif interfaces. The 
> dropping of 
> RX packets is continuous throughout the drbd resync and grows 
> extremely 
> large.
> 
> The ifconfig output within the DomU's do not show any dropped packets.
> 
> I have used iperf to test the performance of the crossover 
> link and it 
> is fine when there is no drbd syncing going on.
> 
> I have tried various things such as setting sysctl.conf options:
> 
> net.core.rmem_default=65536
> net.core.wmem_default=65536
> net.core.rmem_max=16777216
> net.core.wmem_max=16777216
> 
> net.ipv4.tcp_rmem = 4096 87380 16777216
> net.ipv4.tcp_wmem = 4096 65536 16777216
> 
> but so far the only thing that prevents the "PingAck did not 
> arrive in 
> time" errors is to take the sync rate down to 1M.
> 
> 
> 
> My Xen version info is:
> 
> Xen version 3.0.3-1 (Debian 3.0.3-0-4)
> 
> 
> Please advise...
> 
> Thanks!
> 
> _______________________________________________
> Xen-users mailing list
> Xen-users@xxxxxxxxxxxxxxxxxxx
> http://lists.xensource.com/xen-users
> 

______________________________________________________________________
This e-mail, and any attachments thereto, is intended only for use by
the addressee(s) named herein and may contain legally privileged
and/or confidential information. If you are not the intended recipient
of this e-mail, you are hereby notified that any dissemination,
distribution or copying of this e-mail, and any attachments thereto,
is strictly prohibited. If you have received this e-mail in error,
please immediately notify the sender and permanently delete the
original and any copy or printout thereof.


_______________________________________________
Xen-users mailing list
Xen-users@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-users