Block Size; Table 70 Maximum Capacity Of Files And Volumes For Each Block Size - Fujitsu ETERNUS DX S5 Series Design Manual

4. NAS Functions
NAS System (NAS Volume Management)
Caution
During the configuration phase
• The meta cache distribution function can be executed manually or automatically.
If automatic execution is selected, meta cache distribution is executed automatically on a regular basis
(every hour on the half hour) and when a controller is implemented according to the imbalanced state
of the meta cache. When the meta cache distribution function is executed, I/O responses may be
delayed for several tens of seconds to two minutes.
Manual execution is recommended if the I/O response delay becomes an issue.
• The meta cache may be distributed to a controller that is different from the initial deployment in the
following situations.
- When the controller or NAS engine is abnormal, or when the controller is implemented after stopping
for maintenance.
- When the ETERNUS DX is rebooted
Note
During the design phase
Accessing NAS file systems via the NAS interface of the controller where the meta cache is deployed may
enhance performance. The initial meta cache deployment and the IP address of the NAS interface can be
checked using ETERNUS Web GUI or ETERNUS CLI.

Block Size

An optimal block size can be set for the file system according to the operation. In addition, file systems with
different block sizes can exist together in a single ETERNUS DX.
A block size is a unit for managing files within the ETERNUS DX. Files are stored in blocks that are divided into a
fixed size. A small block size minimizes areas used by each file, thereby improving the storage efficiency of a
system that creates many small-sized files.
The block size setting determines the maximum file size and the maximum volume capacity. The following table
shows the maximum file size and the maximum volume capacity for each block size.
Table 70 Maximum Capacity of Files and Volumes for Each Block Size
Block size
8KB
32KB
256KB
Caution
During the configuration phase
• Volumes cannot be expanded to a capacity larger than the maximum volume capacity that is
determined by the block size.
• The block size of the file system cannot be changed after a NAS volume is created.
Maximum file size
1TB
4TB
32TB
169
Maximum volume capacity
32TB
128TB
128TB
Design Guide