Shulou(Shulou.com)05/31 Report--

Thin Provision's example analysis, aiming at this problem, this article introduces the corresponding analysis and answer in detail, hoping to help more partners who want to solve this problem to find a more simple and feasible way.

Automatic downsizing (Thin Provision), sometimes referred to as "oversubscription", is an important emerging storage technology. This paper introduces the automatic simplified configuration, and introduces its working principle, limitations and some suggestions.

If the storage space used by the application is full, it will crash. As a result, storage administrators typically allocate more storage capacity than the application actually needs to avoid any potential application failures. This approach provides "headroom" for future growth and reduces the risk of application failure. However, it requires more physical disk capacity than it actually does, resulting in waste.

Automatic thin configuration software does not need to allocate unused disk capacity in advance, and all storage utilization is higher. Figure 1 shows how a storage administrator traditionally allocates more storage space than an application needs-planning future growth in advance to ensure that the application does not crash because the disk space is full. Volume An in figure 1 has only 100G of physical data, but based on the growth forecast may be allocated much more storage space (500GB, in this case), the unused storage allocated to that volume cannot be used by other applications. In many cases, these 500 GB are never used and are largely wasted. This situation is called "stranded storage".

In popular terms, automatic downsizing is equivalent to blowing balloons in the same room. As long as there are gaps in the room, you can blow up the balloons, which is distributed according to your needs.

In most implementations, automatic thin configuration is based on the principle of "providing storage to applications on demand from a normal storage pool." Automatic thin provisioning can be combined with storage virtualization, which is basically a prerequisite for effective use of this technology. With automatic thin configuration, storage administrators can allocate logical storage (for example, 500G) to applications as usual, but really consume physical capacity only when needed. When the utilization of the storage approaches a predetermined threshold (for example, 90% focus 450G), the array automatically allocates space from the virtual storage pool to extend the volume without the human intervention of the storage administrator. The volume can be overallocated (over allocated) as usual, so the application thinks it has plenty of storage space, but it doesn't actually waste storage space. Automatic thin configuration is an on-demand storage technology that basically eliminates the waste of allocated but unused space.

Automatic thin configuration technology also has some limitations and is not recommended in the following situations:

Data deleted from the volume needs to be recycled, which increases the overhead and cost of the storage controller.

File systems that use unused blocks instead of reusing freed blocks, such as NTFS Microsoft files, cause volumes to increase their maximum allocation size before reusing storage, which reduces the benefits of automatic thin provisioning.

Applications with metadata across the entire volume will reduce the advantage of automatic thin configuration.

If the application wants the data to be contiguous and / or optimize I / O performance around this assumption, using a thin configuration is not a good choice.

However, if the array fails to provide new real storage fast enough, the application will fail. Try to use a high-performance storage controller and a good minotor to monitor the storage over-provisioning to avoid reduced availability.

As auto-thin configuration technology matures, future applications and file systems may be created and re-modified to avoid such problems. The economical and practical reason for automatic streamlining is simple: it automates storage allocation, which significantly reduces the work of storage administrators, and it reduces the amount of storage required by service applications. It also reduces the number of disks required, resulting in a significant reduction in energy consumption.

The main advantage that automatic thin provisioning can provide is to improve the overall utilization of storage space, which should be carefully considered when creating a virtualized data center. However, users should be aware of their considerations and should check the storage and management requirements of the application to avoid making inappropriate choices.

So much for the answers to the sample analysis questions about Thin Provision. I hope the above content can be of some help to you. If you still have a lot of doubts to solve, you can follow the industry information channel for more related knowledge.

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