load average: 0.36, 0.31, 0.28
Tasks: 274 total
0.2%wa

load average: 96.09, 39.48, 15.15
Tasks: 441 total
~60%wa

max_connections = 250
shared_buffers = 16GB
temp_buffers = 16MB
max_prepared_transactions = 0
work_mem = 448MB
maintenance_work_mem = 4GB
max_stack_depth = 6MB
wal_buffers = 18MB
checkpoint_segments = 30
checkpoint_timeout = 5min
checkpoint_warning = 30s
random_page_cost = 4.0
cpu_tuple_cost = 0.01
cpu_index_tuple_cost = 0.005
effective_cache_size = 50GB
default_statistics_target = 100
autovacuum = on

RAM 74 GB
2x Xeon E5606
PostgreSQL 9.1.9, Debian 6
Database size on disc: 84GB data + 23GB indexes. 
RAID 10 15K SCSI.

             total       used       free     shared    buffers     cached
Mem:         72632      71751        881          0        199      67753
-/+ buffers/cache:       3799      68833
Swap:         7627        175       7452

# - Checkpoints -

checkpoint_segments = 30		# in logfile segments, min 1, 16MB each
checkpoint_timeout = 5min		# range 30s-1h
#checkpoint_completion_target = 0.5	# checkpoint target duration, 0.0 - 1.0
checkpoint_warning = 30s		# 0 disables

max_wal_senders = 3
(master-slave репликация)

WARNING:  pgstat wait timeout

#bgwriter_delay = 200ms			# 10-10000ms between rounds
#bgwriter_lru_maxpages = 100		# 0-1000 max buffers written/round
#bgwriter_lru_multiplier = 2.0		# 0-10.0 multipler on buffers scanned/round

autovacuum = on			# Enable autovacuum subprocess?  'on'
					# requires track_counts to also be on.
#log_autovacuum_min_duration = -1	# -1 disables, 0 logs all actions and
					# their durations, > 0 logs only
					# actions running at least this number
					# of milliseconds.
#autovacuum_max_workers = 3		# max number of autovacuum subprocesses
					# (change requires restart)
#autovacuum_naptime = 1min		# time between autovacuum runs
#autovacuum_vacuum_threshold = 50	# min number of row updates before
					# vacuum
#autovacuum_analyze_threshold = 50	# min number of row updates before
					# analyze
#autovacuum_vacuum_scale_factor = 0.2	# fraction of table size before vacuum
#autovacuum_analyze_scale_factor = 0.1	# fraction of table size before analyze
#autovacuum_freeze_max_age = 200000000	# maximum XID age before forced vacuum
					# (change requires restart)
#autovacuum_vacuum_cost_delay = 20ms	# default vacuum cost delay for
					# autovacuum, in milliseconds;
					# -1 means use vacuum_cost_delay
#autovacuum_vacuum_cost_limit = -1	# default vacuum cost limit for
					# autovacuum, -1 means use
					# vacuum_cost_limit

WAL:

#fsync = on				# turns forced synchronization on or off
#synchronous_commit = on		# synchronization level; on, off, or local
#wal_sync_method = fsync

2013-10-16 13:15:44 EEST LOG:  checkpoint starting: time
2013-10-16 13:18:19 EEST LOG:  checkpoint complete: wrote 18099 buffers (0.9%); 0 transaction log file(s) added, 0 removed, 8 recycled; write=149.997 s, sync=5.375 s, total=155.380 s; sync files=224, longest=5.367 s, average=0.023 s
2013-10-16 13:20:50 EEST LOG:  checkpoint starting: time
2013-10-16 13:24:40 EEST LOG:  checkpoint complete: wrote 15063 buffers (0.7%); 0 transaction log file(s) added, 0 removed, 8 recycled; write=92.975 s, sync=94.468 s, total=230.621 s; sync files=195, longest=94.437 s, average=0.484 s
2013-10-16 13:25:50 EEST LOG:  checkpoint starting: time
2013-10-16 13:28:17 EEST LOG:  checkpoint complete: wrote 15419 buffers (0.7%); 0 transaction log file(s) added, 0 removed, 5 recycled; write=134.170 s, sync=7.695 s, total=146.970 s; sync files=212, longest=7.689 s, average=0.036 s

checkpoints_timed 	checkpoints_req 	buffers_checkpoint 	buffers_clean 	maxwritten_clean 	buffers_backend 	buffers_backend_fsync 	buffers_alloc 	stats_reset
51634	339	279759953	1805015	12345	16440091	0	874315771	2013-04-19 17:03:13

checkpoints_timed 	checkpoints_req 	buffers_checkpoint 	buffers_clean 	maxwritten_clean 	buffers_backend 	buffers_backend_fsync 	buffers_alloc 	stats_reset
51641	339	279839908	1805052	12345	16440709	0	874547028	2013-04-19 17:03:13

51641	339	279845447	1805052	12345	16440745	0	874554083	2013-04-19 17:03:13

51641	339	279845447	1805056	12345	16440767	0	874567290	2013-04-19 17:03:13

51642	339	279850635	1805057	12345	16440789	0	874576032	2013-04-19 17:03:13

51642	339	279856316	1805058	12345	16440848	0	874585274	2013-04-19 17:03:13

-work_mem = 448MB
+work_mem = 288MB

maintenance_work_mem = 4GB // решил не менять, т.к. есть очень большие таблицы от 9 до 28 GB 

checkpoint_segments = 30
-checkpoint_timeout = 5min
+checkpoint_timeout = 30min

-cpu_tuple_cost = 0.01
+cpu_tuple_cost = 0.001

(0.001 для быстрых cpu, 0.01 для медленных;)
 
-cpu_index_tuple_cost = 0.005
+cpu_index_tuple_cost = 0.0005

(0.0005 для быстрых cpu, 0.005 для медленных;)

-effective_cache_size = 50GB
+effective_cache_size = 48GB // решил сильно не менять, находится в пределах рекомен. нормы
(effective_cache_size = 0.9 от значения cached, которое показывает free; 0.9*66GB = 59.4GB !?)

ext3    noatime        0       2

io scheduler cfq registered (default)

2.6.32-5-amd64