NFS version 3 reduces the need for Prestoserve(TM) capability. Using the Prestoserve NFS accelerator makes a significant difference with NFS version 2. The Prestoserve NFS accelerator makes only a slight improvement with NFS version 3.
Adding a Prestoserve NFS accelerator with NFS version 2 is another way to improve NFS performance. NFS version 2 requires all writes to be written to stable storage before responding to the operation. The Prestoserve NFS accelerator enables high-speed NVRAM instead of slow disks to meet the stable storage requirement.
Two types of NVRAM used by the Prestoserve NFS accelerator are:
Both types of Prestoserve NFS accelerators speed up NFS server performance by:
Providing faster selection of file systems
Caching writes for synchronous I/O operations
Intercepting synchronous write requests to disk and storing the data in nonvolatile memory
If you can use either NVRAM hardware, use the NVRAM-NVSIMM for the Prestoserve cache. The NVRAM-NVSIMM and SBus hardware are functionally identical. However, the NVRAM-NVSIMM hardware is slightly more efficient and does not require an SBus slot. The NVRAM-NVSIMMs reside in memory and the NVRAM-NVSIMM cache is larger than the SBus hardware.
The NVRAM-NVSIMM Prestoserve NFS accelerator significantly improves the response time of NFS clients with heavily loaded or I/O-bound servers. To improve performance add the NVRAM-NVSIMM Prestoserve NFS accelerator to the following platforms:
SPARCserver 20 system
SPARCserver 1000 or 1000E system
SPARCcenter 2000 or 2000E system
You can use an alternate method for improving NFS performance in Sun Enterprise 3x00, 4x00, 5x00, and 6x00 systems. This method is to upgrade NVRAM in the SPARCstorage Array that is connected to the server.
Sun Enterprise 3x00, 4x00, 5x00, and 6x00 server systems enable SPARCstorage Array NVRAM fast writes. Turn on fast writes by invoking the ssaadm command.
The SBus Prestoserve NFS accelerator contains only a 1 Mbyte cache and resides on the SBus. You can add the SBus Prestoserve NFS accelerator to any SBus-based server except the SPARCserver 1000(E) system, the SPARCcenter 2000(E), or the Sun Enterprise 3x00, 4x00, 5x00, or 6x00 server systems.
Some systems on which you can add the SBus Prestoserve NFS accelerator are:
SPARCserver 5 system
SPARCserver 20 system
Sun Enterprise 1 system
Sun Enterprise 2 system
SPARCserver 600 series