Postgresql size of Slave is bigger than Master size

I have a Postgresql in master slave streaming replication. Master is located in four partitions (tablespaces). df -h on Master shows me

Filesystem      Size  Used Avail Use% Mounted on
***
/dev/md121      880G  490G  346G  59% /mydb/1
/dev/md122      880G  613G  223G  74% /mydb/2
/dev/md123      880G  322G  514G  39% /mydb/3
/dev/md124      880G  506G  330G  61% /mydb/4

but on Slave it takes more disk space on /mydb/4 partition

Filesystem      Size  Used Avail Use% Mounted on
***
/dev/sdb        880G  613G  223G  74% /mydb/2
/dev/sda        880G  448G  388G  54% /mydb/1
/dev/sdc        880G  322G  513G  39% /mydb/3
/dev/sdd        880G  773G   63G  93% /mydb/4

And it grows. WAL files are located in /mydb/1. Where I was mistaken?

Config of Slave

wal_compression = on
autovacuum_naptime = 2s
autovacuum_analyze_scale_factor = 0
autovacuum_vacuum_scale_factor = 0
max_wal_senders = 5
autovacuum_analyze_threshold = 1000
checkpoint_timeout = 40min
temp_buffers = 3000MB
autovacuum_vacuum_threshold = 1000
autovacuum_vacuum_cost_delay = 100ms
wal_keep_segments = 1000
wal_level = hot_standby
autovacuum_vacuum_cost_limit = 5000
autovacuum_max_workers = 6
listen_addresses = '192.168.1.4'
max_wal_size = 100GB
hot_standby = on

Recovery.conf on Slave

standby_mode = 'on'
primary_conninfo = 'user=replication password=mysecretpassword host=master.mydomain.local port=5432 sslmode=prefer sslcompression=1 krbsrvname=postgres'

Config on Master

wal_compression = on
autovacuum_naptime = 2s
autovacuum_analyze_scale_factor = 0
autovacuum_vacuum_scale_factor = 0
max_wal_senders = 5
autovacuum_analyze_threshold = 1000
checkpoint_timeout = 40min
temp_buffers = 1GB
autovacuum_vacuum_threshold = 1000
autovacuum_vacuum_cost_delay = 100ms
wal_keep_segments = 6000
wal_level = hot_standby
autovacuum_vacuum_cost_limit = 5000
autovacuum_max_workers = 6
listen_addresses = '192.168.1.5'
cpu_index_tuple_cost = '0.0005'
wal_buffers = 16MB
checkpoint_completion_target = '0.9'
random_page_cost = 2
maintenance_work_mem = 32GB
max_wal_size = 60GB
synchronous_commit = false
work_mem = 2GB
cpu_tuple_cost = '0.001'
default_statistics_target = 500
effective_cache_size = 96GB