VMware ESX 3.0 has released more than three years, there are many users like to upgrade to the latest VMware virtualization platform vSphere 4.0, and a large number of servers running ESX 3.0 to the need for replacement of the moment.These run for three years the old server, ESX 3.0 Although not fully meet the future needs of the rapidly growing load, but still has not a small performance space, this large number of very expensive server was shut down abandoned, did a bit wasted.In order not to discard the old virtual host in the corner, many companies are re-use of these servers, some companies build their cluster, the load sharing part of the business; and some enterprises will be the old server for testing or training applications.
If you have more than one office or a large campus, to create a hot standby site need to use a lot of hardware, which requires large costs.Then they replaced the old server down can help you save costs, and to these servers for hot backup site, if not a hundred percent commitment to the load, but in some situations better than nothing - in the new server fails,or replace the hardware when a temporary afford business as a backup to avoid business interruption.
So, here we take a look at how to give you a host of new virtualisation virtualization to be a hot backup site hosting it.
Hot backup virtualization host Step 1: Define service levels
First, you need to define your level of service hot backup site is to protect all or part of all servers within the site? You need more than a short recovery time? When do you need to restore the data? Answers to these questions will affect yourarchitecture design process, different service levels also affect the cost of hardware.A hot backup site may need to spend more than you can now afford to be more, in which case your best cost savings, accurate to investment, rather than spending money on useless things.
Hot backup of virtual hosts Step 2: Planning SAN configuration
SAN is the first hardware of concern because it is almost the most expensive part.If possible, the deployment of a hot standby site when the best use of SAN-to-SAN asynchronous replication (asynchronous replication), but depends on the use of SAN platforms, such replication may not be realized or not the economy.For example, if your Web site is not running on iSCSI attached FC SAN, and no dark fiber (dark fiber), in the absence of specific hardware or software, such as FCIP gateways such as EMC's case can not be achieved RepliStor SAN replication.If this is the case you later upgrade or replace the SAN when we must consider these factors.On the other hand, some of the equipment for the use of brand users need to pay attention to some issues, such as NetApp SnapMirror user should add more licenses.
If you can not perform SAN to SAN replication, you also have some other options.There are some good host-based replication software package that can run on ESX host, host to host to achieve a direct copy, including Vizioncore vReplicator and NSI DoubleTake, etc., but note that the license is per virtual machine rather than per host.There should be noted that the old host to do hot backup connection when the need to give them a lot of storage, because if the old host is connected to the SAN, will no longer have their own hard drive.
No matter how you intend to do, whether SAN or host-based replication, storage virtualization configuration is designed to be hot backup site host the most important part, need to be considered carefully.
Hot backup virtualization host Step 3: Calculate bandwidth requirements
Select a good host for your virtual hot backup site with which storage, you need to consider how to transfer data.If your virtual host hot backup site is through the optical fiber connection, then do not worry too much about bandwidth issues, unless the data is very huge.However, the calculation of the bandwidth is very important, because the bandwidth of the long term is not correct calculation of the additional costs is also very significant.For example, imagine you have two first T1 line (3.0Mbps) to meet every 24 hours about 25GB of data backup, but the practical applications you need to copy the data found in a day or so to have 35GB, which is almost expected to be worsethe bandwidth of a T1 line.Do not underestimate these seemingly small differences in these three years in the rental cost of bandwidth may be a new SAN or the cost of several virtual hosts as much.
Therefore, replication bandwidth requirements calculation is very important, need a reliable way to calculate.One of the most simple way is to use VMware's snapshot feature built-in, you need to back up the virtual machine to create a snapshot, wait for a replication cycle, and then check your VMFS volume snapshot file size, this figure can be roughly calculated inThis cycle of changes in the amount of data the virtual machine.Of course, this method can also calculate the virtual machines in different time period, the data changes.
However, according to the different SAN platforms, SAN replication block than VMware's snapshot files may be large, the virtual machine a 1KB file storage to SAN may want to become a 16MB, magnified 16,000 times.However, this situation is rare, indicating that the file can not be completely under the snapshot replication to estimate the actual amount of data.
To solve this problem, and to increase the capacity of WAN links 传输, the use of WAN with duplicate data removed accelerator is a wise choice attributes such as Cisco's WAAS or Riverbed's Steelhead and so on.Both platforms have their own advantages and disadvantages, but essentially the same, you can only optimize the WAN data stream and has many other TCP enhancements, and before the WAN connection for remote cache retention, to solve the data from 1KB16MB of data into the problem.
Hot backup virtualization host Step 4: Identify needs of virtualization software licenses
The final consideration is your virtualization host hot backup site how much virtualization license.Of course, you can not permit one to configure ESX hosts, failure in the active site to permit migrated to this host.Another way is to buy VMware vSphere Essentials license, although the characteristics of your activities on the site, compared with some restrictions, but can also start and run virtual machines.
Another problem is to consider whether you need to deploy VMware's Site Recovery Manager, SRM require SAN to SAN replication, and the price is not cheap.However, if you need regular checks of your recovery plan or need a fully automatic data recovery process, deployment of SRM is very necessary.
Re-use old hardware is a good idea
Using old hardware to recommend a hot spare for the reuse of data centers is a good way of resources, but the blind to create a virtual host of hot backup site, regardless of how much you can take advantage of surplus hardware, it will not get very goodeffect.Remember these things: to develop an appropriate goal, consider storage resources, carefully estimate the WAN bandwidth, consider the software license restrictions, can effectively reduce costs and achieve maximum efficiency.
As technology advances, today's virtualization technology, constantly updated storage and network technology, to create a fault-tolerant real-time online system is also not a problem, if you need high-availability systems, now is the time of the handsthe.