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0
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0answers
9 views

Apache Mesos Master on every node

Is it good idea to launch mesos master and mesos slave together on every node? If no, how to calc number of master nodes?
0
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1answer
22 views

Azure Traffic Manager fault tolerance

I have just answered Do I need Azure Traffic Manager with Azure API Services? Over on SO Part of my answer was understanding the failure of all aspects of a solution to which I realised I really ...
2
votes
1answer
81 views

Systemd does not restart service, although Restart=always

Here is my unit file of a systemd service: [Unit] Description=Tunnel For %i After=network.target [Service] User=autossh ExecStart=/usr/bin/autossh -M 0 -N -o "ExitOnForwardFailure yes" -o ...
2
votes
2answers
31 views

Fault Tolerance with Windows Server Failover Clusters?

I've attempted to read numerous articles online about this and believe I'm "seeing the light", but I'd like to have it confirmed. Do Windows Server Failover Clusters offer a fault-tolerant feature ...
0
votes
0answers
17 views

PSU voltage sag tolerance

I am interested in learning how tolerable my hardware to power loss due to switching between circuits (via transfer switch) or due to lag when line-interactive UPS kicks in. I have several servers ...
0
votes
1answer
104 views

Does balance-alb and balance-tlb support fault-tolerance?

I've read bonding.txt file of kernel documentation, it's clear about load balance, but are balance-alb and balance-tlb really fault tolerant?
2
votes
2answers
99 views

mdadm fault injection testing with bad blocks or other unrecoverable errors

I recently lost a drive in my RAID array (and got an email from the system warning me of this, which was awfully nice) and after some drive shuffling and swapping in a new drive I'm all safe and ...
1
vote
1answer
38 views

Fault-tolerance/Failover in school project [closed]

I'm taking a course on distributed architecture. The course participants are divided into groups. Each group must develop an MMORPG-type console game and set up the infrastructure. The lecturer has a ...
3
votes
1answer
250 views

Distributed mirrored filesystem under FreeBSD

Can someone share their experience in building a distributed mirrored filesystem between multiple FreeBSD machines? I. e. we have two (three, four...) servers and special partition "part1" mounted on ...
1
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0answers
121 views

Can I use a reverse-proxy on a hosting service to redirect connections to multiple IPs while taking care of maintaining sessions?

I have a situation where I am trying to host my own web server because I need some custom software, including telephony, WebRTC, node.js, etc. However, my net connection in the town and country where ...
1
vote
0answers
33 views

VMware ESXi - what happens when unable to create a secondary instance of a VM for fault tolerance

Is anyone aware what would happen if VMware ESXi is unable to start back up a secondary instance of a VM configured for fault tolerance? Is there a fallback plan to try and get the VM up? Or is the VM ...
4
votes
1answer
286 views

VMware High Availability questions

I can't seem to find the answers to these questions within the vSphere 5 Documentation center, so please share if you are aware of any aspects of these questions. What happens to the failed VM that ...
2
votes
1answer
684 views

Combine 2 logical raid 0 drives to 1 logical raid 1 drive

I have an HP Proliant server with an P410i embedded array controller. The server was originally setup with 6 physical drives with the OS on 1 logical drive with a raid 0 and 5 physical drives setup ...
0
votes
1answer
217 views

vSphere High Availability, Fault Tolerance and Snapshots

I've heard claims from a vSphere server administrator that VMs configured for high availability continue to transparently function even in the event of an ESXi host failure. He also claims VMs ...
-1
votes
2answers
132 views

Never miss a HTTP post [closed]

I have a webservice that have a couple of "machine" clients connected to it that does HTTP post with data once in a while. The nature of the service is that I cant allow the service to loose a single ...
1
vote
1answer
493 views

PHP - Memcached - Libmemcached - Handle cache server outage

I am working on ensuring our app degrades gracefully in case of a complete cache outage, which is highly unlikely, as we have minimum of at least 3 cache nodes to add to the cache pool, by way of ...
1
vote
0answers
220 views

What database am I seeding from in a stretched DAG?

I have a stretched DAG across 2 sites, with 4 copies. One of the remote copies failed, and I issued a re-seed operation with the remote&working copy as a source. Knowing this, I tried to work ...
0
votes
2answers
337 views

pfsense CARP - wan failure on firewall

I have recently configured 2 firewall (on 2 DELL PowerEdge R210II with ESXI 5.1) with pfsense. We have several LANs and 2 WANs. Everything is running fine but i have a strange behavior: i can access ...
-4
votes
1answer
60 views

Is it possible to use planet scale load-balanced virtulisation? [closed]

there are more and more implementations of distributed-virtualisation. A common one is Microsoft SCVMM. Currently, such things are kept inside LANs, and a san or fiber-channel system is used for ...
2
votes
2answers
427 views

When to employ server failover in a virtual environment

This question kind of got me thinking about fault tolerance in DHCP, so I did a little digging in my current environment and discovered that we only have 1 DHCP server per major site in our company ...
6
votes
3answers
5k views

Is round-robin DNS a possible solution for high availability?

Let's say I have 2 IPs for a given domain (round-robin DNS). If one the IPs becomes unresponsive, will clients try to connect to the other IP? or they will just fail to establish comunication with the ...
2
votes
2answers
1k views

Detect HP ML370 G5 Bad disk in RAID0

I have one HP ML370 G5 server. Which has four 146GB SAS disks and two 300GB SAS disks that are configured as RAID 0. I have encountered a problem with one of my disks. The windows server event viewer ...
0
votes
1answer
1k views

VMware ESXi/vSphere Fault Tolerance vCPU Limit

So I am aware that VMs in FT mode are limited to a single vCPU. Is it possible to assign multiple cores to the single vCPU, and still have the VM support FT mode? Or are you forced to use both a vCPU ...
0
votes
2answers
622 views

What Are VMware ESXi/vSphere Fault Tolerance Bandwidth Requirements

I plan on deploying a cluster of 2 ESXi/vSphere servers and having them run in fault tolerance mode. The virtual servers primarily be IIS & SQL. The physical servers will have a single Xeon ...
0
votes
2answers
618 views

Microsoft licensing in a virtualized environment questions [duplicate]

I plan on deploying two physical servers which will run VMware ESXi and have a number of questions regarding Microsoft licensing. To note, all the VMs on the servers will be configured to run in ...
0
votes
2answers
41 views

Can I control which DNS record a client application uses?

I'm trying to make our set of servers more fault tolerant. I have a web server, a mail server and a PBX server that uses SIP. I know that for each service, I can have the DNS return multiple A, MX ...
-1
votes
2answers
67 views

What software should I use for fault tolerence/high availability for 2 servers [closed]

What are some of the industry standard enterprise software to allow fail-over or swap-over between 2 servers? E.g., if 1 server goes down(due to connection or power, etc), the other kicks in either ...
1
vote
1answer
551 views

What is the importance of “RpcClientAccessServer” on a database in an Active/Active stretched DAG?

I have two sites with a stretched DAG between them. By "sites" I mean two AD sites that correspond with different physical and network circuits. When I take an individual mailbox database and move ...
0
votes
1answer
321 views

RAID 5 - DELL 2850 and others

I have installed Ubuntu on a DELL 2850 and I have configured an array of 5 disks (SCSI 73GB 10K) in RAID5. I wanted to simulate a drive error so in the middle of something I just took one of the ...
1
vote
2answers
704 views

Dell PERC H700 and 8 disk slots : what are my options to increase disk fault tolerance?

We've got a Dell PowerEdge T510 which has 8 disk slots in the front. It is currently utilising 6 of these slots, and the disks are controlled by a PERC H700 controller. The disks are currently running ...
1
vote
1answer
466 views

Advantage of Microsoft Cluster over Microsoft Network Load Balancer

Till recently, I assumed that Microsoft NLB worked at an OS/Machine level rather than an Application Level. i.e. the NLB just monitors heartbeats on the machine to check if machine is alive and then ...
4
votes
1answer
150 views

What TLDs should I use for my NS records for redundancy? (DNSSEC support required)

Question As a general practice, is it a good idea to use multiple TLDs for the name servers? How should I choose between which TLD would be a good candidate for being the root server for my NS ...
1
vote
2answers
1k views

Record DNS for 2 static ip - fault tolerance

i've a web server in a DMZ reachable from 2 different public static ip addresses provided by 2 different internet connection by 2 different ISPs. I want to create a record let's say ...
1
vote
1answer
157 views

Why state is needed for keepalived

From the doc ! MASTER and BACKUP state are determined by the priority ! even if you specify MASTER as the state, the state will ! be voted on by priority (so if your state is MASTER but your ! ...
0
votes
2answers
119 views

Stratus Servers vs Virtualised Machines as a High Availability Solution [closed]

I've been asked to do this as a presentation, but to be honest, either I've totally missed the point or am I being asked to compare an actual company i.e. Stratus against the concept of virtualising ...
-4
votes
1answer
1k views

how to configure ISCSI fault tolerance in ubuntu 12.04 [closed]

how to configure ISCSI fault tolerance in ubuntu 12.04 Anyone has a tutorial or steps to?! thanks in advance knowing that initiator and server are ubuntu
6
votes
1answer
2k views

Azure Virtual Machines - what fault tolerance do they provide?

We are thinking about moving our virtual machines (Hyper-V VHDs) to Windows Azure but I haven't found much about what kind of fault tolerance that infrastructure provides. When I run VHD in Azure, ...
0
votes
1answer
83 views

webserver cluster serving web content using a SAN still results in a single point of failure

I'm looking for a better way of doing things than using a SAN lun mounted to multiple webservers as a way of keeping data in sync. The applications require instantaneous or near instantaneous ...
4
votes
3answers
992 views

How to properly configure power redundancy for devices with only one power input?

Some devices, such as servers and high-end switches have dual PSUs/power inputs, which can then be hooked up to separate UPSes, which are hooked up to separate power circuits (correct so far, right?). ...
3
votes
3answers
3k views

What happens if an OpenStack cloud controller dies?

I've been reading up on OpenStack and how we can re-create an EC2/S3-style cloud for our internal development and I'm having a hard time finding information on how the OpenStack cloud controller ...
8
votes
2answers
2k views

Multi-site high availability

We have a SaaS application that we need to be highly available. We already have an expensive, well-maintained Hyper-V failover cluster, but today the datacenter where we host that cluster had a ...
2
votes
1answer
2k views

ClearOS - how to avoid getting stuck at a fsck message at boot?

I have had this happen a couple times - I have a ClearOS Enterprise 5.2 box, and due to a power outage or similar, it ends up showing an error at boot and saying that fsck needs to be run (I think it ...
4
votes
2answers
4k views

Redundant NFS on Amazon EC2

I'm interested in building two fault tolerant/redundant NFS servers with failover at Amazon EC2. I'm familiar with tools/technologies like DRBD, Heartbeat, etc. Does Amazon provide any specific way of ...
0
votes
1answer
806 views

Fault-tolerant KVM hosts

I'm going to create a simple virtual hosts infrastructure using QEMU+KVM. It is expected to be very simple, without clouds or any other cool things. Right now the only requirement is the ...
1
vote
2answers
1k views

keepalived questions (requirements, abilities, limitations)

1) What are keepalived's (physical/network) requirements? Does the two (or more) keepalived' nodes need to be connected to the same switch? (something related to broadcasting maybe). 2) Can ...
0
votes
1answer
58 views

Is the Blackberry “Move Server” command a reliable way to achieve redundancy?

BES supports moving more than one user in a domain to an alternate server as shown in the image below. Does this mean I could achieve some level of redundancy by moving users from one BES server to ...
1
vote
2answers
1k views

haproxy failover with process monitoring?

I know some people are using keepalived and heartbeat for active/standby but what action is taken if the haproxy process were to die? What would be nice is if the virtual IP would switch servers if ...
7
votes
3answers
3k views

Do I need a second RAID controller for fault-tolerance?

I have a server with 3 hard drives installed, and a total capacity of 6. We're planning to max it out, but our consultant also suggested getting a second RAID controller "for redundancy" to support ...
1
vote
0answers
234 views

Basic solution for IP address failover on Windows

I'm trying to find a basic solution that will allow an IP address to fail over from one Win2k3 server to a standby one. I've got my own programs that can detect when a failure has occurred and trigger ...
1
vote
1answer
316 views

True memory-synchronous write flushing — drbd protocol B-?

Is there a way in DRBD to make a real fully memory-synchronous cache? I might best explain substituting current explanation with my own one: Protocol B. Memory synchronous (semi-synchronous) ...