Managing NFS and KRPC Kernel Configurations in HP-UX 11i v3 (762807-002, June 2014)

The nfs3_srv_read_copyavoid tunable controls the server-side read copy avoidance feature
for NFSv3 filesystems. For more information on this tunable, see nfs3_srv_read_copyavoid.
Tested Values
Default: 0 (Server-side read copy avoidance feature is
disabled) Min: 0
Max: 1 (Server-side read copy avoidance feature is enabled)
Note: Before you enable this tunable, you should
install the Virtual Memory fix (SR: 8606472738)
included in patch
PHKL_36457.
Restrictions on Changing
The nfs2_srv_read_copyavoid tunable is dynamic. System reboot is not required to
activate changes made to this tunable. Only NFSv2 mount points are affected by
changing the value of this tunable.
Modifying the Value
Enable this tunable to potentially improve the performance of applications that issue read
requests in NFSv2 filesystems.
Warning: Under certain circumstances, enabling
the
nfs2_srv_read_copyavoid/nfs3_srv_read_copyavoi
d tunable may cause the following problems:
– Memory corruption with the message
block getting corrupted
(QXCR1000879579)
– Data corruption during READ, when the
nfs2_bsize/ nfs3_bsize tunable value is
greater than 64 KB
(QXCR1000855994)
HP recommends disabling the
nfs2_srv_read_copyavoid/nfs3_srv_read_cop
yavoid tunables until these problems have
been fixed. Fixes for these problems are
planned for a future ONCplus release.