Using Linux and GFS to create Cluster Storage (1)

Use Linux and GFS to create Cluster Storage (1)-Linux general technology-Linux technology and application information. The following is a detailed description. We often need to provide a central address for data through NFS (Network File System) or other mechanisms to share the file system. Although your security mechanism may protect you from faults on Web server nodes, you still need to share data through central storage nodes.
GFS-a Linux free Cluster File System-allows you to create a truly stable cluster without relying on other servers. In this article, we will show you how to correctly set GFS.
In terms of concept, a cluster file system can allow multiple operating systems to load the same file system and write data to the same file system at the same time. There are many cluster file systems, including Sun's Lustre, Oracle's OCFS (Oracle cluster file system), and Linux's GFS.
There are many ways to make a block device be used by multiple servers at the same time. You can partition a SAN (storage LAN) LUN (logical unit number) visible to multiple servers, and set the corresponding iSCSI (Internet small computer system interface ), or use DRBD (Distributed replication block device) to copy a partition between two servers. When using DRBD, you need to set DRBD in the master/master node to use GFS.
GFS requirements
Running GFS means you are running a cluster. So far, the simplest way to run GFS is to use Red Hat Cluster Suite (RHCS: Red Hat Cluster Suite ). This suite is available in CentOS. In addition, you need the following packages: cman -- Cluster Manager; lvm2-cluster -- so that LVM (logical volume manager) can support the CLVM (cluster logical volume manager) package of the cluster; kmod-gfs -- GFS kernel module; finally gfs-utils.
The Cluster Manager (cman) contains necessary tools, such as the distributed lock manager. Unless you want to spend time figuring out how different distribution versions use cman, we strongly recommend CentOS or RHEL. at the same time, you will also get the latest version of cluster Services maintained by RH (Red Hat), and you can also get a stable environment.
Fencing is absolutely necessary. In some guiding articles, we recommend that you set the blocking mode to "Manual", because the blocking setting may be complicated. Blocking means isolating the cluster or immediately interrupting the operation of some dangerous nodes. If the cluster cannot block a faulty node, your GFS will have many problems, so do not skip this step.