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1
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1answer
59 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
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0answers
51 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
96 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 ...
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votes
1answer
50 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
102 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 ...
4
votes
3answers
913 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
366 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
0answers
107 views

Make a fault tolerance platform with 2 servers (PGsql/Nginx) on Centos 6.4

I have two dedicated servers. Currently one is configured with PGsql (8.4) and nginx (php-fpm+SSL verisign) on a centOS 6.4. I just got the second one. To explain context, on one hand, I have a ...
0
votes
1answer
566 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 ...
1
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2answers
219 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
206 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
35 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 ...
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2answers
50 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
77 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
156 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
392 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
246 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
101 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
511 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
130 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
104 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 ...
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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
1k 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, ...
-1
votes
1answer
113 views

What's the best way to know if your web server goes down? [duplicate]

Possible Duplicate: What tool do you use to monitor your servers? I noticed my website only got 8 visitors today, which means it probably went down very early this morning and I never ...
0
votes
1answer
67 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
562 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
2k 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 ...
7
votes
2answers
622 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
1k 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 ...
3
votes
2answers
3k 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
598 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
691 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
52 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 ...
0
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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
1k 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
190 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
185 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) ...
1
vote
4answers
554 views

Stress test a server for simultaneous connection

I am trying to figure out a practical way to stress test a server for 300 to 600 simultaneous connections. Any advice? Thank you everyone for the help. To be more specific (sorry I wasn't before) ...
2
votes
2answers
580 views

Can we run a mix of vSphere Standard and Advanced but still use Advanced features?

We have a vSphere cluster of 4 ESXi servers licensed for Standard. We want to purchase some Advanced licenses so that we can use the Fault Tolerance feature in vSphere, but we don't want to upgrade ...
8
votes
3answers
2k views

Fault-tolerant NFS?

Probably a FAQ but I haven't found anything useful after a while of searching: Can I set up NFS in such a way that every single error (e.g. server CPU, hard disk, hd controller, network adapter, ...
3
votes
1answer
2k views

Keepalived not sending mutlicast advertisments

I have two systems, both VMs. The are configured to use Bridged networking. I am trying to get keepalived to manage ownership of a VIP - 10.190.1.230. I have tried two versions of keepalived-1.2.2 and ...
4
votes
1answer
436 views

SQL Server 2008 R2 100% availability

Is there any way to provide 100% uptime on SQL Server 2008 R2? From my experience, the downtimes for the different replication methods are: Log Shipping: Lots (for DR only) Mirroring w. NLB: ~ 45 ...
1
vote
1answer
344 views

fault tolerant file systems

some filesystems like btrfs and lustre are marked as fault tolerant file systems in : wiki:http://en.wikipedia.org/wiki/List_of_file_systems what's meaning of fault tolerant file system at all? does ...
1
vote
2answers
171 views

Windows Server 2008 Enterprise edition (cluster's ip address)?

My question is first of all for guys who had experience with Windows Server 2008 R2 Enterprise edition. As i found i can bake cluster (Failover Cluster Nodes). This cluster gives me one ip adress. So ...
0
votes
3answers
608 views

Round robin DNS and fault tolerance (web service, windows 2008)?

What "Round robin DNS" services do you know/use? I am interesting in free and commercial variants. I have domain and a few ip addresses from each server. But i think that some servers (Windows Sever ...
5
votes
3answers
759 views

*nix CARP or VMWare Fault Tolerance?

We're experimenting with what VMWare called a "Fully Collapsed DMZ" on blade centre. Basically our DMZ goes straight into a vSwitch and all the security appliances are virtualised. I've spent days ...
1
vote
1answer
431 views

VMWare FT, 10GbE, 4 NICs - possible?

I'm trying to investigate if VMWare FT will be available in the following networking configuration. We have 4x 10GbE NIC's, two of which are for the MPIO iSCSI networking, which leaves 2x NICs for ...
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2answers
433 views

Best option for HA between remote datacentres?

We're reviewing the system requirements that a new client has brought to us. They work in the medical field and the system they want us to host must be at a minimum highly available, and preferably ...
0
votes
1answer
187 views

Sharepoint 2010 Foundation Fault Tolerance

Assuming a completely reliable SQL Server infrastructure (i.e. SQL Server is not part of the question), what is the simplest and cheapest (i.e. minimum number of servers) method of making a ...
2
votes
1answer
191 views

How do IP addresses transfer when using VMware Fault Tolerance?

I've been doing some thinking about VMware Fault Tolerance and I have a question about the networking side of things. I'll state how I think it works, and you can tell me where i'm wrong. Lets say we ...