Constraints

This section describes the constraints on the use of OBS features.

**Table 1** OBS use restrictions
Restriction Item	Description
Capacity utilization for small files	A small file defined by OBS is an object smaller than 200 KB. A small file stored in OBS will occupy more physical storage space than its actual size. This results in low space utilization. A single OBS node supports only a limited number of objects. In massive storage scenarios, smaller files will result in a lower space utilization. To store a large number of small files, you are advised to plan the storage capacity and storage nodes separately to prepare for capacity expansion.
Access rule	In consideration of the DNS resolution performance and reliability, OBS requires that the bucket name must precede the domain when a request carrying a bucket name is constructed to form a three-level domain name, also mentioned as virtual-hosted-style access domain name.