vSphere Storage - ESXi 5.1 - Documentation - VMware
vSphere Storage - ESXi 5.1 - Documentation - VMware
vSphere Storage - ESXi 5.1 - Documentation - VMware
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<strong>vSphere</strong> <strong>Storage</strong><br />
File-Based (VMFS) Solution<br />
When you use an <strong>ESXi</strong> system in conjunction with a SAN, you must decide whether file-based tools are more<br />
suitable for your particular situation.<br />
When you consider a file-based solution that uses <strong>VMware</strong> tools and VMFS instead of the array tools, be aware<br />
of the following points:<br />
n Using <strong>VMware</strong> tools and VMFS is better for provisioning. One large LUN is allocated and<br />
multiple .vmdk files can be placed on that LUN. With an RDM, a new LUN is required for each virtual<br />
machine.<br />
n Snapshotting is included with your <strong>ESXi</strong> host at no extra cost.<br />
n Using VMFS is easier for <strong>ESXi</strong> administrators.<br />
n <strong>ESXi</strong> administrators who use the file-based solution are more independent from the SAN administrator.<br />
Third-Party Management Applications<br />
You can use third-party management applications in conjunction with your <strong>ESXi</strong> host.<br />
Most SAN hardware is packaged with storage management software. In many cases, this software is a web<br />
application that can be used with any web browser connected to your network. In other cases, this software<br />
typically runs on the storage system or on a single server, independent of the servers that use the SAN for<br />
storage.<br />
Use this third-party management software for the following tasks:<br />
n <strong>Storage</strong> array management, including LUN creation, array cache management, LUN mapping, and LUN<br />
security.<br />
n Setting up replication, check points, snapshots, or mirroring.<br />
If you decide to run the SAN management software on a virtual machine, you gain the benefits of running a<br />
virtual machine, including failover using vMotion and <strong>VMware</strong> HA. Because of the additional level of<br />
indirection, however, the management software might not be able to see the SAN. In this case, you can use an<br />
RDM.<br />
NOTE Whether a virtual machine can run management software successfully depends on the particular storage<br />
system.<br />
SAN <strong>Storage</strong> Backup Considerations<br />
Having a proper backup strategy is one of the most important aspects of SAN management. In the SAN<br />
environment, backups have two goals. The first goal is to archive online data to offline media. This process is<br />
repeated periodically for all online data on a time schedule. The second goal is to provide access to offline data<br />
for recovery from a problem. For example, database recovery often requires retrieval of archived log files that<br />
are not currently online.<br />
Scheduling a backup depends on a number of factors:<br />
n Identification of critical applications that require more frequent backup cycles within a given period of<br />
time.<br />
n Recovery point and recovery time goals. Consider how precise your recovery point needs to be, and how<br />
long you are willing to wait for it.<br />
n The rate of change (RoC) associated with the data. For example, if you are using<br />
synchronous/asynchronous replication, the RoC affects the amount of bandwidth required between the<br />
primary and secondary storage devices.<br />
32 <strong>VMware</strong>, Inc.