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authorRick Macklem <rmacklem@FreeBSD.org>2021-09-18 21:38:43 +0000
committerRick Macklem <rmacklem@FreeBSD.org>2021-09-18 21:38:43 +0000
commitad6dc365202390edffb14d725155e230b96f59ae (patch)
tree7d7f3093f1c1d51283e456f4c15ad0aa996c7e57 /release
parent7b2ac8eb9be76c96356b6e9a7c06a8080ea841ae (diff)
nfscl: Use vfs.nfs.maxalloclen to limit Deallocate RPC RTT
Unlike Copy, the NFSv4.2 Allocate and Deallocate operations do not allow a reply with partial completion. As such, the only way to limit the time the operation takes to provide a reasonable RPC RTT is to limit the size of the allocation/deallocation in the NFSv4.2 client. This patch uses the sysctl vfs.nfs.maxalloclen to set the limit on the size of the Deallocate operation. There is no way to know how long a server will take to do an deallocate operation, but 64Mbytes results in a reasonable RPC RTT for the slow hardware I test on. For an 8Gbyte deallocation, the elapsed time for doing it in 64Mbyte chunks was the same (within margin of variability) as the elapsed time taken for a single large deallocation operation for a FreeBSD server with a UFS file system.
Diffstat (limited to 'release')
0 files changed, 0 insertions, 0 deletions