5.3.1 Disk Subsystem
The file server disk subsystem contains the files which are accessed by the LAN workstations. The efficiency at which access is performed is directly related to the file server performance. The following section describes some of the findings of the IBM PC Server performance laboratory on the major factors that affect hard disk subsystem performance.
5.3.1.1 Block Size and Cache Buffer Size (NetWare 3.12)
NetWare V3.12 allows you to set the cache buffer size in system memory and the block size on the physical hard disk. Matching these values can help balance the workload of the CPU and the DASD subsystem, thereby yielding an overall higher throughput. It also improves file read/write retrieval time for a user on a LAN workstation.
Block Size: The volume block size can be set when the volume is created using the INSTALL.NLM facility.
Default =4KB
Range = 4KB, 8KB, 16KB, 32KB and 64KB (NetWare 3.12)
Cache Buffer Size: The cache buffer size can be set in the STARTUP.NCF file using the following format:
SET CACHE BUFFER SIZE=VALUE
Default value = 4KB
Range = 4KB - 16KB (NetWare 3.12)
Recommendation: Set the block size to 8192 (8KB). The cache buffer size should be set to 8192 bytes also. These two values are closely related and complement each other with respect to performance. Matching their size helps to match
In some cases, the adjusting of the block size parameter to match the cache buffer size might not be as important as other considerations for the setting of the block size. For example, a 64KB volume block size might be needed for installing a multimedia application. This would be more important to users ′ overall performance than would the matching of the block size to the cache buffer size.
In the absence of these kind of requirements, use the values in the following table to relate volume block size to cache buffer size.
Table 17. Volume Block Size and Cache Buffer Size Recommendations
Volume Block Size in KB | Cache Buffer Size in bytes |
|
|
4 | 4096 |
|
|
8 | 8192 |
|
|
16 | 16384 |
|
|
32 | 16384 |
|
|
64 | 16384 |
|
|
