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Questions tagged [high-availability]

High availability is an architectural consideration often involving degrees of redundancy to insure availability in case of system or component failure.

High availability is an architectural consideration often involving degrees of redundancy to insure availability in case of system or component failure. Highly available systems are commonly implemented in situations where the risk outweighs the cost.

Best practices such as change control, standardized procedures, and monitoring can also enable high availability.

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How to lower Gluster FS down peer timeout / reduce down peer impact?

The setting: Two fresh CentOS 6.5 server with latest updates. Both have a fresh install of Gluster 3.5.2. What I did ( from the perspective of server 2, shared1 and shared2 are logical volumes ) : wget -P /etc/yum.repos.d…
Robert
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How to perform cron jobs failover?

Using two Debian servers, I need to setup a strong failover environment for cron jobs that can be only called on one server at a time. Moving a file in /etc/cron.d should do the trick, but is there a simple HA solution to operate such action ? And…
Falken
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Keepalived's virtual_router_id - should it be unique per node?

I have two nodes running keepalived, and two VIP, e.g. Node 1 Node 2 VIP1 VIP2 So in each node, I have two definition of vrrp_instance, so I assume the two vrrp_instance in my keepalived.conf suppose to be unique, but they can be the…
Ryan
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Is there a way to force heartbeat to add new ip addresses to the system without a full restart?

We utilize heartbeat for High Availability. I'd like to add an additional ip address to the heartbeat cluster, but I don't want to do a full restart of the cluster in the process. Is there a signal I can send to heartbeat that would prompt it to…
Peter Grace
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KVM+DRBD replicated between two active-passive servers with manual switching

I need to build 2-node cluster(-like?) solution in active-passive mode, that is, one server is active while the other is passive (standby) that continuously gets the data replicated from active. KVM-based virtual machines would be running on active…
LetMeSOThat4U
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OpenVPN HA Setup on AWS

We are using Paid version of OpenVPN on AWS. Now we want to setup HA but we could not find any proper solution for OpenVPN HA on AWS. Tried OpenVPN document but it doesn't meet the requirement of HA on AWS. Can anyone share/suggest best solution…
sanjayparmar
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LIO iSCSI Target for Windows Server 2016 Cluster disk - device is not ready

I have a LIO iSCSI Target configured on a Fedora 22 machine exporting 1 LUN to 2 Windows Server 2016 machines, both of these are able to access the disk without issues. These servers are part of a HA Cluster and when I attempt to add the disk to…
James Hirst
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How do multiple backup servers work in Nginx?

For the backup directive, The Nginx documentation states rather minimally: marks the server as a backup server. It will be passed requests when the primary servers are unavailable. What if you have multiple backups and the primary server goes…
Benny Bottema
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Clustering and/or Hyper-V replica?

We currently have one big Dell server T610 physically hosting 4 Hyper-V VMs all Win2008R2. Running smoothly for years. We now need to purchase a new Dell server since Dell won't renew the existing service contract's 'end-of-life' T610. We're a small…
Mr. Raspberry
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Any problems with having an active/active HAProxy setup with Keepalived

Apologies if this has been asked before, but I can't seem to find much on it. We're going to be using HAProxy to load balance our MariaDB Galera Cluster. All the articles/tutorials I have seen on this use Keepalived (or something similar) for an…
Luke Cousins
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Why doesn't VMWare DRS automatically migrate VMs when a host is put in maintenance mode?

We have 4 ESXi 5.0 hosts in a VMWare cluster on shared storage (NFS) with DRS and HA on. We want to perform a memory upgrade on one of the hosts. We put that host in maintenance mode but DRS did not automatically live migrate the VMs. I'm thinking…
Belmin Fernandez
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How to scale up a web server supporting long polling

I am planing to add more web application servers to support increasing clients, deploying HAproxy and Keepalived for load balancing and High availability. My server usage has the following characteristic: Jobs are not CPU intensive. Message are…
Mickey
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Should an HA failover occur in this scenario?

I'm running vSphere 5 in an HA cluster across two hosts (vsphereA and vsphereB). I have the HA cluster configured for host monitoring and datastore heartbeat monitoring with admission control disabled (hopefully I rightfully understand that…
joeqwerty
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HAProxy -- pause/queue all traffic without losing requests

I basically have the same problem as mentioned in this thread -- I would like to temporarily suspend all requests to all servers of a certain backend, so that I can upgrade the backend and the database it uses. Since this is a live system, I would…
Marc
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If DNS Failover is not recommended, what is?

As a followup question to his very popular question: Why is DNS failover not recommended?, I think it was agreed that DNS failover is not 100% reliable due to caching. However the highest voted answer did not really discuss what is the better…
IMB
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