Dell Unity: Overview of Quota Policies
Summary: A Dell Unity Quota Tree allows administrators to limit the amount of storage consumed by a specific directory within a file system, while Quota Policies determine how usage is calculated. ...
Instructions
In Dell Unity, a Quota Tree is a quota that is applied to a specific directory (folder) within a file system. Unlike a user quota, which restricts how much space a user can consume, a quota tree restricts how much space a particular directory can consume regardless of which user writes the data.
For example, if a file system contains:
/engineering/projects/engineering/backups/engineering/archive
You could create a quota tree on:
/engineering/backups
Then, you could limit that directory to 5 TB. Once the quota is reached, additional writes to that directory can be restricted based on the configured quota settings.
Dell Unity Quota Policies
Before enabling quotas, Unity allows you to choose how quota usage is calculated for the file system. This is referred to as the Quota Policy.
File Size Quota Policy (Default)
The File Size quota policy calculates disk usage based on the logical file size in 1 KB increments.
Characteristics:
- Default quota policy.
- Calculates usage based on the logical size of files rather than actual allocated storage.
- A file's reported size may be larger than the actual consumed storage if the file contains holes (sparse files).
- Generally recommended for Windows/
SMBenvironments where users expect quotas to reflect the file sizes they see in Windows Explorer.
Block Quota Policy
The Block quota policy calculates usage based on actual file system block allocation. Dell Unity uses file system blocks in 8 KB units and tracks the allocation and removal of those blocks.
Characteristics:
- Measures actual storage consumed on disk.
- Includes block allocations associated with files, directories, and symbolic links.
- More accurately reflects physical space consumption.
- Recommended for
UNIX/Linux/NFSenvironments.
Summary
| Quota Policy | Usage Calculation | Recommended Environment |
|---|---|---|
| File Size (Default) | Logical file size in 1 KB increments | Windows / SMB |
| Block | Actual allocated file system blocks (8 KB units) | UNIX / Linux / NFS |
When discussing a Quota Tree Policy on a Unity array, it usually means a directory-level quota (Quota Tree) that is enforced using one of the two available Quota Policies—File Size or Block—to determine how storage consumption is calculated.