pg_basebackup is taking an unusually long time with Postgres 11.3

Hi Folks,

I am having trouble setting up replication with Postgres 11.3.
pg_basebackup is taking an unusually long time for an small Postgres
database. Anything wrong in my configuration or anything I could do to
speed up pg_basebackup?

I recently upgraded form Postgres 9.2.1. Using a similar postgres
configuration, apart from some updates to config for Postgres 11.3. I am
using pg_basebackup to replicate from the master. I am using secure ssh
tunnel for the replication between master and slave, I.e. there is a ssh
tunnel that forwards data from the localhost on port 5433 on the slave to
the master server’s port 5432.

pg_basebackup is taking about 30 seconds.

c12-array2-c1:/# du ./path/to/database

249864 ./nimble/var/private/config/versions/group/sodb

pg_basebackup -D $PGSQL_BASEBKUP_PATH -U $DBUSER -c fast -l $backup_name -h
localhost -p 5433 --wal-method=stream -Pv -s 10

postgresql.conf:

….

max_connections = 100 # (change requires restart)

# Note: Increasing max_connections costs ~400 bytes of shared memory per

# connection slot, plus lock space (see max_locks_per_transaction).

#superuser_reserved_connections = 3 # (change requires restart)

unix_socket_directories = '/var/run/postgresql' # (change requires
restart)

…..

# - Security and Authentication -

#authentication_timeout = 1min # 1s-600s

#ssl = off # (change requires restart)

#ssl_ciphers = 'ALL:!ADH:!LOW:!EXP:!MD5:@STRENGTH' # allowed SSL
ciphers

# (change requires restart)

#ssl_renegotiation_limit = 512MB # amount of data between
renegotiations

#ssl_cert_file = 'server.crt' # (change requires restart)

#ssl_key_file = 'server.key' # (change requires restart)

#ssl_ca_file = '' # (change requires restart)

#ssl_crl_file = '' # (change requires restart)

#password_encryption = on

#db_user_namespace = off

# Kerberos and GSSAPI

#krb_server_keyfile = ''

#krb_srvname = 'postgres' # (Kerberos only)

#krb_caseins_users = off

# - TCP Keepalives -

# see "man 7 tcp" for details

#tcp_keepalives_idle = 0 # TCP_KEEPIDLE, in seconds;

# 0 selects the system default

#tcp_keepalives_interval = 0 # TCP_KEEPINTVL, in seconds;

# 0 selects the system default

#tcp_keepalives_count = 0 # TCP_KEEPCNT;

# 0 selects the system default

…..

shared_buffers = 32MB # 32 or 300MB based on model

# (change requires restart)

#temp_buffers = 8MB # min 800kB

….

work_mem = 10MB # min 64kB

#maintenance_work_mem = 16MB # min 1MB

…..

wal_level = replica # minimal, archive, or hot_standby

# (change requires restart)

#fsync = on # turns forced synchronization on
or off

#synchronous_commit = on # synchronization level;

# off, local, remote_write, or on

wal_sync_method = open_sync # the default is the first option

# supported by the operating system:

# open_datasync

# fdatasync (default on Linux)

# fsync

# fsync_writethrough

# open_sync

#full_page_writes = on # recover from partial page writes

#wal_buffers = -1 # min 32kB, -1 sets based on
shared_buffers

# (change requires restart)

#wal_writer_delay = 200ms # 1-10000 milliseconds

#commit_delay = 0 # range 0-100000, in microseconds

#commit_siblings = 5 # range 1-1000

# - Checkpoints -

#checkpoint_segments = 3 # in logfile segments, min 1, 16MB
each

checkpoint_timeout = 1min # range 30s-1h

#checkpoint_completion_target = 0.5 # checkpoint target duration, 0.0 -
1.0

#checkpoint_warning = 30s # 0 disables

# - Archiving -

archive_mode = on # allows archiving to be done

# (change requires restart)

archive_command = '/bin/true' # command to use to archive a logfile segment

# placeholders: %p = path of file to archive

# %f = file name only

# e.g. 'test ! -f /mnt/server/archivedir/%f
&& cp %p /mnt/server/archivedir/%f'

#archive_timeout = 0 # force a logfile segment switch after this

# number of seconds; 0 disables

…..

max_wal_senders = 10 # max number of walsender processes

# (change requires restart)

wal_keep_segments = 10 # in logfile segments, 16MB each; 0 disables

wal_sender_timeout = 10s # in milliseconds; 0 disables

# - Master Server -

# These settings are ignored on a standby server.

synchronous_standby_names = '' # standby servers that provide sync rep

# comma-separated list of application_name

# from standby(s); '*' = all

#vacuum_defer_cleanup_age = 0 # number of xacts by which cleanup is
delayed

# - Standby Servers -

# These settings are ignored on a master server.

hot_standby = on # "on" allows queries during recovery

# (change requires restart)

#max_standby_archive_delay = 30s # max delay before canceling queries

# when reading WAL from archive;

# -1 allows indefinite delay

#max_standby_streaming_delay = 30s # max delay before canceling queries

# when reading streaming WAL;

# -1 allows indefinite delay

wal_receiver_status_interval = 3s # send replies at least this often

# 0 disables

#hot_standby_feedback = off # send info from standby to prevent

# query conflicts