Re: [CentOS] Question about clustering

2014-06-18 Thread Alessandro Baggi
Il 17/06/2014 16:32, Digimer ha scritto: On 17/06/14 10:23 AM, Denniston, Todd A CIV NAVSURFWARCENDIV Crane wrote: -Original Message- From: Digimer [mailto:li...@alteeve.ca] Sent: Monday, June 16, 2014 3:20 PM To: CentOS mailing list Subject: Re: [CentOS] Question about clustering

Re: [CentOS] Question about clustering

2014-06-18 Thread John R Pierce
On 6/18/2014 9:32 AM, Alessandro Baggi wrote: Ok, fencing is a requirement for a cluster for hardware failure. I've another question about this arg, but for software failure. Supposing to have a cluster of httpd installation on 6 virtualized hosts, each one on a different server. Suppose also

Re: [CentOS] Question about clustering

2014-06-18 Thread Digimer
On 18/06/14 12:32 PM, Alessandro Baggi wrote: Ok, fencing is a requirement for a cluster for hardware failure. I've another question about this arg, but for software failure. Supposing to have a cluster of httpd installation on 6 virtualized hosts, each one on a different server. Suppose also

Re: [CentOS] Question about clustering

2014-06-18 Thread m . roth
Digimer wrote: On 18/06/14 12:32 PM, Alessandro Baggi wrote: Ok, fencing is a requirement for a cluster for hardware failure. I've another question about this arg, but for software failure. Supposing to have a cluster of httpd installation on 6 virtualized hosts, each one on a different

Re: [CentOS] Question about clustering

2014-06-18 Thread SilverTip257
On Wed, Jun 18, 2014 at 2:46 PM, m.r...@5-cent.us wrote: Digimer wrote: On 18/06/14 12:32 PM, Alessandro Baggi wrote: Ok, fencing is a requirement for a cluster for hardware failure. I've another question about this arg, but for software failure. Supposing to have a cluster of httpd

Re: [CentOS] Question about clustering

2014-06-17 Thread Denniston, Todd A CIV NAVSURFWARCENDIV Crane
-Original Message- From: Digimer [mailto:li...@alteeve.ca] Sent: Monday, June 16, 2014 3:20 PM To: CentOS mailing list Subject: Re: [CentOS] Question about clustering On 16/06/14 02:55 PM, m.r...@5-cent.us wrote: SNIP One can also set the cluster nodes to failover, and when

Re: [CentOS] Question about clustering

2014-06-17 Thread Digimer
On 17/06/14 10:23 AM, Denniston, Todd A CIV NAVSURFWARCENDIV Crane wrote: -Original Message- From: Digimer [mailto:li...@alteeve.ca] Sent: Monday, June 16, 2014 3:20 PM To: CentOS mailing list Subject: Re: [CentOS] Question about clustering On 16/06/14 02:55 PM, m.r...@5-cent.us

Re: [CentOS] Question about clustering

2014-06-16 Thread Alessandro Baggi
Hi Digimer, there is a chance to make fencing without hardware, but only software? Il 15/06/2014 17:28, Digimer ha scritto: On 15/06/14 08:54 AM, Alessandro Baggi wrote: Another question is about fencing. I've ridden that a cluster must have fencing to be considered as such. On CentOS 6.5

Re: [CentOS] Question about clustering

2014-06-16 Thread Digimer
No. For fencing to be worthwhile, it *must* work when the node is in any state. For this, it must be independent of node. A great way to see why is to test crashing the node (echo c /proc/sysrq-trigger) or simply cutting the power to the node. With the node totally disabled, the surviving

Re: [CentOS] Question about clustering

2014-06-16 Thread John R Pierce
On 6/16/2014 2:39 AM, Alessandro Baggi wrote: Hi Digimer, there is a chance to make fencing without hardware, but only software? the most common fence in TCP connected systems is to disable the ethernet ports of the fenced system, done via a 'smart ethernet switch'. if you're using shared

Re: [CentOS] Question about clustering

2014-06-16 Thread Digimer
On 16/06/14 01:36 PM, John R Pierce wrote: On 6/16/2014 2:39 AM, Alessandro Baggi wrote: Hi Digimer, there is a chance to make fencing without hardware, but only software? the most common fence in TCP connected systems is to disable the ethernet ports of the fenced system, done via a 'smart

Re: [CentOS] Question about clustering

2014-06-16 Thread John R Pierce
On 6/16/2014 10:55 AM, Digimer wrote: The main downside to fabric fencing is that the failed node will have no chance of recovering without human intervention. Further, it places the onus on the admin to not simply unfence the node without first doing proper cleanup/recovery. For these

Re: [CentOS] Question about clustering

2014-06-16 Thread Digimer
On 16/06/14 02:19 PM, John R Pierce wrote: On 6/16/2014 10:55 AM, Digimer wrote: The main downside to fabric fencing is that the failed node will have no chance of recovering without human intervention. Further, it places the onus on the admin to not simply unfence the node without first doing

Re: [CentOS] Question about clustering

2014-06-16 Thread m . roth
Digimer wrote: On 16/06/14 02:19 PM, John R Pierce wrote: On 6/16/2014 10:55 AM, Digimer wrote: The main downside to fabric fencing is that the failed node will have no chance of recovering without human intervention. Further, it places the onus on the admin to not simply unfence the node

Re: [CentOS] Question about clustering

2014-06-16 Thread Digimer
On 16/06/14 02:55 PM, m.r...@5-cent.us wrote: Digimer wrote: On 16/06/14 02:19 PM, John R Pierce wrote: On 6/16/2014 10:55 AM, Digimer wrote: The main downside to fabric fencing is that the failed node will have no chance of recovering without human intervention. Further, it places the onus

[CentOS] Question about clustering

2014-06-15 Thread Alessandro Baggi
Hi list, I'm new to clustering, and I'm running a little cluster@home. The cluster is running on a workstation hardware and running on Centos 6.5. Component: corosync, pacemaker, drbd and pcs. All works good. This cluster has different resources: 1) drbd0 2) drbd1 3) drbd0_fs 4) drbd1_fs 5)

Re: [CentOS] Question about clustering

2014-06-15 Thread Digimer
On 15/06/14 08:54 AM, Alessandro Baggi wrote: Another question is about fencing. I've ridden that a cluster must have fencing to be considered as such. On CentOS 6.5 there is stonith that concerns node level fencing. For this type of fencing I must have ilo, ilom, drac, and other. It's