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Re: [Xen-users] Alternatives to a dual-primary DRBD setup

To: Daniel Meszaros <meszi@xxxxxxxxxxx>
Subject: Re: [Xen-users] Alternatives to a dual-primary DRBD setup
From: Bart Coninckx <bart.coninckx@xxxxxxxxxx>
Date: Fri, 20 May 2011 21:28:34 +0200
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On 05/20/11 20:51, Daniel Meszaros wrote:
Hi there,

usually I am just lurking around here collecting ideas about issues that I could run into in the future but now it seems my time has come to ask for your help...

Until now I ran a Citrix Xenserver 5.6 on a dual-primary DRBD setup. But for any reason I am experiencing sync problems now, maybe due to the raised I/O load (setup without guest machines, now ten virtual servers).

I am tapping a bit in darkness at searching for the needle in the haystack causing the problems. Therefore I am thinking about possible alternatives that allow useful things like XenMotion but possibly at a lower performance usage level.

My current setup:
- two servers with dual 12-core Opterons and 32 GB RAM, each
- each server equipped with a 500 MB (hardware) RAID1 for the host and with a 14 TB (hardware) RAID5 for the guests that's being replicated using DRBD
- each server with a 10 GbE NIC
- Citrix Xenserver 5.6, both running in one pool

What are your ideas? Is it worth thinking about other storage solutions?


Xen-users mailing list

To me it sounds your setup should be fine. It does depends on the nature of your guests of course. 10 is not a lot though.

I would try to find the bottleneck:

- do an effective measurement of the DRBD link with netperf
- investigate none of your guests is swapping heavily consuming a lot of I/O
- investigate your disk performance. RAID5 is not ideal, more striping would be better.

I don't think you're very likely to have better performance with other setups, like iSCSI.


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