Comments inline. On 26-Jan-2014, at 11:14 am, Shanker Balan <shanker.ba...@shapeblue.com> wrote:
> Comments inline. > > On 26-Jan-2014, at 10:10 am, Francois Gaudreault <fgaudrea...@cloudops.com> > wrote: > >> Yes, we tried with a NetScaler, but as soon as one MySQL dies, both >> management servers fence themselves on DB exceptions :S > > > Does Galera maintain client connection state across the failover? I was not able to get much information but Looks like it does not manage sessions across the cluster. So if a node fails, all sessions currently handled by the node will eventually timeout and fail. It is up to the client now to open new connections. One way to work around the session handling issue would be to use a L7 proxy that can talk MySQL. I think mysql-proxy can do that but its alpha(?) s/w. Also, mysql-proxy itself is not HA. The other way would be to make the whole fault tolerance an app problem. If the app could automagically reconfigure itself to do round robin writes across the galera cluster based on health checks, we will get “HA” automatically. A failed node would end up being blacklisted by the app. As of now, I don’t see any other way other than to force a CloudStack restart in response to a galera node failure. Hoping someone with more db-foo can tell us more. -- @shankerbalan M: +91 98860 60539 | O: +91 (80) 67935867 shanker.ba...@shapeblue.com | www.shapeblue.com | Twitter:@shapeblue ShapeBlue Services India LLP, 22nd floor, Unit 2201A, World Trade Centre, Bangalore - 560 055 Need Enterprise Grade Support for Apache CloudStack? Our CloudStack Infrastructure Support<http://shapeblue.com/cloudstack-infrastructure-support/> offers the best 24/7 SLA for CloudStack Environments. Apache CloudStack Bootcamp training courses **NEW!** CloudStack 4.2.1 training<http://shapeblue.com/cloudstack-training/> 18th-19th February 2014, Brazil. Classroom<http://shapeblue.com/cloudstack-training/> 17th-23rd March 2014, Region A. Instructor led, On-line<http://shapeblue.com/cloudstack-training/> 24th-28th March 2014, Region B. Instructor led, On-line<http://shapeblue.com/cloudstack-training/> 16th-20th June 2014, Region A. Instructor led, On-line<http://shapeblue.com/cloudstack-training/> 23rd-27th June 2014, Region B. Instructor led, On-line<http://shapeblue.com/cloudstack-training/> This email and any attachments to it may be confidential and are intended solely for the use of the individual to whom it is addressed. Any views or opinions expressed are solely those of the author and do not necessarily represent those of Shape Blue Ltd or related companies. If you are not the intended recipient of this email, you must neither take any action based upon its contents, nor copy or show it to anyone. Please contact the sender if you believe you have received this email in error. Shape Blue Ltd is a company incorporated in England & Wales. ShapeBlue Services India LLP is a company incorporated in India and is operated under license from Shape Blue Ltd. Shape Blue Brasil Consultoria Ltda is a company incorporated in Brasil and is operated under license from Shape Blue Ltd. ShapeBlue is a registered trademark.
