Managing NFS and KRPC Kernel Configurations in HP-UX 11i v2 (Oct 2008)

Restrictions on Changing
The nfs3_jukebox_delay tunable is dynamic. System reboot is not required to activate a change made
to this tunable. Only NFSv3 mount points are affected when you change the value of this tunable.
Modifying the Value
If it takes a considerable amount of time for files to migrate from your HSM storage devices, increase
the value of this tunable. However, if you increase the value of the tunable, it can prevent the file from
becoming immediately visible when it becomes available.
If files are migrated quickly from your HSM storage devices, decrease the value of this tunable. If you
decrease the value of the tunable, you can view the file as soon as it becomes available. However, if
you set the tunable too low, your client can send retransmissions before the server is able to retrieve
the files from the HSM storage devices.
2.1.19 nfs3_max_transfer_size
Description
The nfs3_max_transfer_size tunable specifies the maximum size of the data portion of NFSv3 READ,
WRITE, READDIR, and READDIRPLUS requests. This parameter controls both the maximum size of the
data that the server returns and the maximum size of the request the client generates.
The nfs3_max_transfer_size tunable works in conjunction with the nfs3_max_transfer_size_cots and
nfs3_max_transfer_size_clts tunables when determining the maximum size of these I/O requests. For
NFSv3 TCP traffic, the transfer size corresponds to the smaller value of nfs3_max_transfer_size and
nfs3_max_transfer_size_cots. For UDP traffic, the transfer size corresponds to the smaller value of
nfs3_max_transfer_size and nfs3_max_transfer_size_clts.
Tested Values
Default: 32768
Min: 4096
Max: 65536
Note: If the tunable is set to a value less than 4096 or
greater than 65536, an informational warning is issued at
runtime. These values are outside the tested limits.
Restrictions on Changing
The nfs3_max_transfer_size tunable is dynamic. System reboot is not required to activate changes
made to this tunable. However, the transfer size for a filesystem is set when the filesystem is mounted.
In order to affect a particular filesystem, you must unmount and re-mount the filesystem after changing
this tunable. Only NFSv3 mount points are affected by changing the value of this tunable.
Modifying the Value
For NFS/TCP Filesystems:
To increase the transfer size of NFSv3 TCP requests, set the nfs3_max_transfer_size and
nfs3_max_transfer_size_cots tunables to the same value. Otherwise, the transfer size will default to the
smaller value of these tunables. For example, if 64 KB transfers are desired, both tunables must be set
to at least 64 KB. If one of the tunables is set to 64 KB and the other is set to 32 KB, the transfer size
is 32 KB because that is the smaller value of the two tunables.
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