The concept of AJAX will be used to eventually develop a fully functional OS on the web webOS and applications there are already so many of them that will make almost everything virtual--a kind of IBM mainframe concept, where you get your space on a big fat server somewhere. OS, Network, almost everything will be virtual.
Certainly, security and performance will be the biggest challenges to organizations worldwide. Oracle recently launched the Database Vault , which I think is a very smart move. That will be the motto when we all go out on the web. There is already a RHEL 4. So what will we be doing? The following lines must be present:.
Now this can be pretty tricky. As a rule of thumb, for development purposes, I go ahead and do a complete install. If you follow the installation procedure for RHEL 4.
To ensure the correct operation of a cluster, you must configure the required kernel settings, as described in the following table.
Specifies the number of seconds after a panic before a system automatically resets itself. If the value is 0, the system hangs, which allows you to collect detailed information about the panic for troubleshooting. This is the default value. To enable automatic reset, set a non-zero value. If you require a memory image vmcore , allow enough time for Kdump to create this image.
The suggested value is 30 seconds, although large systems will require a longer time. Specifies that a system must panic if a kernel oops occurs. If a kernel thread required for cluster operation crashes, the system must reset itself.
Otherwise, another node might not be able to tell whether a node is slow to respond or unable to respond, causing cluster operations to hang. There are several commands that you can use to administer the cluster stack.
The following table describes the commands for performing various operations on the cluster stack. You use the mkfs. If you want to label the volume and mount it by specifying the label, the device must correspond to a partition. You cannot mount an unpartitioned disk device by specifying a label. The following table describes some useful options that you can use when creating an OCFS2 volume.
The supported block sizes are bytes , 1K, 2K, and 4K. The default and recommended block size is 4K 4 kilobytes. Specifies the unit size for space used to allocate file data. The default cluster size is 4K 4 kilobytes. Enables support for the sparse files, unwritten extents, and inline data features.
Enables only those features that are understood by older versions of OCFS2. Enables all features that OCFS2 currently supports. Enables you to enable or disable individual features such as support for sparse files, unwritten extents, and backup superblocks. For more information, see the mkfs. Specifies the size of the write-ahead journal.
If not specified, the size is determined from the file system usage type that you specify to the -T option, and, otherwise, from the volume size. Specifies a descriptive name for the volume that allows you to identify it easily on different cluster nodes. Determines the maximum number of nodes that can concurrently access a volume, which is limited by the number of node slots for system files such as the file-system journal.
For best performance, set the number of node slots to at least twice the number of nodes. If you subsequently increase the number of node slots, performance can suffer because the journal will no longer be contiguously laid out on the outer edge of the disk platter. Database files are typically few in number, fully allocated, and relatively large. Such files require few metadata changes, and do not benefit from having a large journal.
Mail server files are typically many in number, and relatively small. Such files require many metadata changes, and benefit from having a large journal. Virtual machine image files are typically few in number, sparsely allocated, and relatively large. Such files require a moderate number of metadata changes and a medium sized journal. The following table provides suggested recommendations for minimum cluster size settings for different file system size ranges.
You cannot change the block and cluster size of an OCFS2 volume after you have created it. You can use the tunefs. For more information, see the tunefs. If you intend that the volume store database files, do not specify a cluster size that is smaller than the block size of the database. The default cluster size of 4 KB is not suitable if the file system is larger than a few gigabytes. The following examples show some of the ways in which you can create an OCFS2 volume.
The default values are a 4 KB block and cluster size, eight node slots, a MB journal, and support for default file-system features:. In this case, the cluster size is set to KB and the journal size to 32 MB. For the file system to mount, you must enable the o2cb and ocfs2 services to start after networking is started. Use the tunefs. For example, to find out the label, UUID, and number of node slots for a volume, you would use the following command:.
The following procedure describes how to create an OCFS2 file system to be mounted locally, which is not associated with a cluster. To create an OCFS2 file system that is to be mounted locally, use the following command syntax:. The previous example also increases the number of node slots from 1 to 8, to allow up to eight nodes to mount the file system. Refer to the following information when investigating how to resolve issues that you might encounter when administering OCFS2.
It is recommended that you set up netconsole on the nodes to capture an oops trace. Part 8 - Clone VM oralin11 to oralin Part 9 - Configure Second Node: oralin Contact Please email any comments and suggestions to: sybase reygrobellet. Contents 1 Architecture 1. Select "Remove disk from virtual drive".
Backup old Sybase Installation. Shutdown Cluster. INFO - Shutdown of cluster mycluster has completed successfully. Shutdown Agents To do on both nodes. This mount point is backed by the same LUN in the SAN, but most importantly the filesystem is aware that there are multiple hosts connected to it and will lock files accordingly. Glenn spends most of his time designing and implementing IaaS solutions based on on Apache CloudStack.
He has designed and implemented numerous CloudStack environments for customers across 4 continents, based on Apache CloudStack. Some say; that when not building Clouds, Paul likes to create Ansible playbooks that build clouds. But… Clustered File Systems If you need to have a volume shared between two or more hosts, you can provision the disk to all the machines, and everything might appear to work, but each host will be maintaining its own inode table and so will be unaware of changes other hosts are making to the file system, and in the event that writes ever happened to the same areas of the disk at the same time you will end up with data corruption.
Options There are dozens of clustered file systems out there, proprietary and open source.
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