openstack/swift
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Add read and write affinity options to deployment guide

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Add entries for these options in the deployment guide and
make the text in proxy-server.conf-sample and man page
consistent.

Change-Id: I5854ddb3e5864ddbeaf9ac2c930bfafdb47517c3
This commit is contained in:
Alistair Coles 2017-05-04 16:47:38 +01:00
parent 582af7cd9d
commit f02ec4de81
3 changed files with 78 additions and 27 deletions
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46
doc/manpages/proxy-server.conf.5
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@ -1026,26 +1026,42 @@ Set to the number of nodes to contact for a normal request. You can use '* repli
at the end to have it use the number given times the number of at the end to have it use the number given times the number of
replicas for the ring being used for the request. The default is '2 * replicas'. replicas for the ring being used for the request. The default is '2 * replicas'.
.IP \fBread_affinity\fR .IP \fBread_affinity\fR
Which backend servers to prefer on reads. Format is r<N> for region Specifies which backend servers to prefer on reads. Format is a comma
N or r<N>z<M> for region N, zone M. The value after the equals is separated list of affinity descriptors of the form <selection>=<priority>.
the priority; lower numbers are higher priority. The <selection> may be r<N> for selecting nodes in region N or r<N>z<M> for
Default is empty, meaning no preference. selecting nodes in region N, zone M. The <priority> value should be a whole
Example: first read from region 1 zone 1, then region 1 zone 2, then anything in region 2, then everything else: number that represents the priority to be given to the selection; lower numbers
read_affinity = r1z1=100, r1z2=200, r2=300 are higher priority. Default is empty, meaning no preference.
Example: first read from region 1 zone 1, then region 1 zone 2, then anything
in region 2, then everything else:
.PD 0
.RS 10
.IP "read_affinity = r1z1=100, r1z2=200, r2=300"
.RE
.PD
.IP \fBwrite_affinity\fR .IP \fBwrite_affinity\fR
Which backend servers to prefer on writes. Format is r<N> for region Specifies which backend servers to prefer on writes. Format is a comma
N or r<N>z<M> for region N, zone M. If this is set, then when separated list of affinity descriptors of the form r<N> for region N or
handling an object PUT request, some number (see setting r<N>z<M> for region N, zone M. If this is set, then when handling an object
write_affinity_node_count) of local backend servers will be tried PUT request, some number (see setting write_affinity_node_count) of local
before any nonlocal ones. Default is empty, meaning no preference. backend servers will be tried before any nonlocal ones. Default is empty,
meaning no preference.
Example: try to write to regions 1 and 2 before writing to any other Example: try to write to regions 1 and 2 before writing to any other
nodes: nodes:
.PD 0
.RS 10
write_affinity = r1, r2 write_affinity = r1, r2
.RE
.PD
.IP \fBwrite_affinity_node_count\fR .IP \fBwrite_affinity_node_count\fR
The number of local (as governed by the write_affinity setting) The number of local (as governed by the write_affinity setting) nodes to
nodes to attempt to contact first, before any non-local ones. You attempt to contact first on writes, before any non-local ones. The value
can use '* replicas' at the end to have it use the number given should be an integer number, or use '* replicas' at the end to have it use
times the number of replicas for the ring being used for the the number given times the number of replicas for the ring being used for the
request. The default is '2 * replicas'. request. The default is '2 * replicas'.
.IP \fBswift_owner_headers\fR .IP \fBswift_owner_headers\fR
These are the headers whose values will only be shown to swift_owners. The These are the headers whose values will only be shown to swift_owners. The

32
doc/source/deployment_guide.rst
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@ -1794,6 +1794,38 @@ ionice_priority None I/O scheduling priority of server
I/O priority of the process. Work I/O priority of the process. Work
only with ionice_class. only with ionice_class.
Ignored if IOPRIO_CLASS_IDLE is set. Ignored if IOPRIO_CLASS_IDLE is set.
read_affinity None Specifies which backend servers to
prefer on reads; used in conjunction
with the sorting_method option being
set to 'affinity'. Format is a comma
separated list of affinity descriptors
of the form <selection>=<priority>.
The <selection> may be r<N> for
selecting nodes in region N or
r<N>z<M> for selecting nodes in
region N, zone M. The <priority>
value should be a whole number
that represents the priority to
be given to the selection; lower
numbers are higher priority.
Default is empty, meaning no
preference.
write_affinity None Specifies which backend servers to
prefer on writes. Format is a comma
separated list of affinity
descriptors of the form r<N> for
region N or r<N>z<M> for region N,
zone M. Default is empty, meaning no
preference.
write_affinity_node_count 2 * replicas The number of local (as governed by
the write_affinity setting) nodes to
attempt to contact first on writes,
before any non-local ones. The value
should be an integer number, or use
'* replicas' at the end to have it
use the number given times the number
of replicas for the ring being used
for the request.
============================ =============== ===================================== ============================ =============== =====================================
[tempauth] [tempauth]

27
etc/proxy-server.conf-sample
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@ -200,9 +200,12 @@ use = egg:swift#proxy
# replicas for the ring being used for the request. # replicas for the ring being used for the request.
# request_node_count = 2 * replicas # request_node_count = 2 * replicas
# #
# Which backend servers to prefer on reads. Format is r<N> for region # Specifies which backend servers to prefer on reads. Format is a comma
# N or r<N>z<M> for region N, zone M. The value after the equals is # separated list of affinity descriptors of the form <selection>=<priority>.
# the priority; lower numbers are higher priority. # The <selection> may be r<N> for selecting nodes in region N or r<N>z<M> for
# selecting nodes in region N, zone M. The <priority> value should be a whole
# number that represents the priority to be given to the selection; lower
# numbers are higher priority.
# #
# Example: first read from region 1 zone 1, then region 1 zone 2, then # Example: first read from region 1 zone 1, then region 1 zone 2, then
# anything in region 2, then everything else: # anything in region 2, then everything else:
@ -210,11 +213,11 @@ use = egg:swift#proxy
# Default is empty, meaning no preference. # Default is empty, meaning no preference.
# read_affinity = # read_affinity =
# #
# Which backend servers to prefer on writes. Format is r<N> for region # Specifies which backend servers to prefer on writes. Format is a comma
# N or r<N>z<M> for region N, zone M. If this is set, then when # separated list of affinity descriptors of the form r<N> for region N or
# handling an object PUT request, some number (see setting # r<N>z<M> for region N, zone M. If this is set, then when handling an object
# write_affinity_node_count) of local backend servers will be tried # PUT request, some number (see setting write_affinity_node_count) of local
# before any nonlocal ones. # backend servers will be tried before any nonlocal ones.
# #
# Example: try to write to regions 1 and 2 before writing to any other # Example: try to write to regions 1 and 2 before writing to any other
# nodes: # nodes:
@ -222,10 +225,10 @@ use = egg:swift#proxy
# Default is empty, meaning no preference. # Default is empty, meaning no preference.
# write_affinity = # write_affinity =
# #
# The number of local (as governed by the write_affinity setting) # The number of local (as governed by the write_affinity setting) nodes to
# nodes to attempt to contact first, before any non-local ones. You # attempt to contact first on writes, before any non-local ones. The value
# can use '* replicas' at the end to have it use the number given # should be an integer number, or use '* replicas' at the end to have it use
# times the number of replicas for the ring being used for the # the number given times the number of replicas for the ring being used for the
# request. # request.
# write_affinity_node_count = 2 * replicas # write_affinity_node_count = 2 * replicas
# #