Red Hat CLUSTER SUITE FOR ENTERPRISE LINUX 5.1 Manual do Utilizador Página 1

INTRODUCTION TO LINUX CLUSTERINGDOCUMENT RELEASE 1.1Copyright 2008 Jethro CarrThis document may be freely distributed provided that it is not modified

Introduction to Linux Clusteringservers.Other fencing devices include fencing at the SAN level as well as Xen VM fencing, however it is recommended th

Introduction to Linux Clusteringquorum to unbalance the quorum voting.Effectively, quorum allows you to make an even cluster, uneven when it comes to

Introduction to Linux Clustering 5 Cluster management softwareTo control the cluster and the movement of services, a cluster management application is

Introduction to Linux ClusteringWhen a cluster node fails, the services that are running on it need to be migrated to other machines. The cluster mana

Introduction to Linux Clustering● Setup a device on the network (eg: a reverse-proxy or session balancing application) that passes the session traffic

Introduction to Linux Clustering 6 Combining Xen with clustersVirtualization technology is becoming increasingly popular due to the reduced costs and

Introduction to Linux Clustering 7 Storage ManagementStorage management may appear to be a separate topic, but it is in fact a very important part of

Introduction to Linux ClusteringCentralised storage systems typically export the disk space as a block device which appears on the nodes as a local di

Introduction to Linux Clustering 7.1.2 NAS – NETWORK ATTACHED STORAGEA NAS is a hardware device consisting of a RAID array of hard drives (like a SAN)

Introduction to Linux Clusteringbest result, whereas others may find the performance of a SAN to be better.Also consider future expandability – if you

Introduction to Linux Clustering 7.3.3 Coda...

Introduction to Linux Clusteringincrease performance when using a TCP-based storage service like iSCSI. 7.2 Access methods for centralised storageWhil

Introduction to Linux Clustering 7.3 Distributed StorageDistributed storage takes another approach to the storage mechanism, and instead of having a c

Introduction to Linux Clustering 7.3.3 CODACoda is an interesting filesystem with features for allowing offline data caching for client computers, as

Introduction to Linux ClusteringDRBD can be configured to work in one of two ways:● Primary/Secondary – The storage device can only be mounted on one

Introduction to Linux Clustering 7.5 Clustered FilesystemsWhen using a block-level storage system like iSCSI, SAN, GNBD or DRBD a cluster capable file

Introduction to Linux Clustering 8 Cluster Examples and ChallengesThere are numerous ways you can configure a cluster, which will depend on your requi

Introduction to Linux ClusteringIn the event of any node failing, Redhat Cluster Suite will move all the services to the alternate node and switch DRB

Introduction to Linux ClusteringSome installations use SANs which limits the cluster size by the number of interfaces on the SAN. However, SANs are ve

Introduction to Linux Clustering 8.3 Five node HA cluster with DRBD + XenThe five-node DRBD cluster design above can be extended to become a HA Xen cl

Introduction to Linux Clusteringsolved:● Internet connections are slow – data needs to be mirrored at both sites in a way that is bandwidth friendly a

Introduction to Linux Clustering© Copyright 2008 Jethro Carr Page 3/33

Introduction to Linux Clusteringload balance between your geographically separated servers – this is good for services such as HTTP or read-only datab

Introduction to Linux Clustering 8.4.2 THREE+ NODE DISTRIBUTED CLUSTERThe two-node distributed cluster detailed above will work fine with two-nodes, b

Introduction to Linux ClusteringThis is covered in more details in the DRBD filesystem section earlier in this document, but basically you divide the

Introduction to Linux Clustering 9 Further ReferenceThe following resources are good further reading for information on setting up cluster solutions:C

Introduction to Linux Clustering 1 IntroductionOne of the oldest problems of computing is designing failure proof computing systems. Over the years, m

Introduction to Linux Clustering 2 About clustersThere are three main reasons to use clustering:● Better performance● Fault tolerance by high availabi

Introduction to Linux Clustering 3 Advantages and reasons for clusteringClustering provides a number of advantages over traditional standalone server

Introduction to Linux Clusteringmigrate a service from one computer to another, which can sometimes be required due to security or performance reasons

Introduction to Linux Clustering 4 Clustering fundamentals 4.1 Basics High-availability clustering is a complex topic, and it is important to fully un

Introduction to Linux Clustering1. Hot failover In a hot failover, the application is written specially for clustering and is able to continue runni