Hi,
I have problem to run postgresql on ubuntu 24.04 server with huge_pages = on. My instance have 8GB ram and 2 vcpus (t3a.large). My configuration is:
max_connections = 1000
superuser_reserved_connections = 3
shared_buffers = 1960MB
effective_cache_size = 5881MB
huge_pages = on
temp_buffers = 32MB
max_prepared_transactions = 100
work_mem = 1MB
maintenance_work_mem = 392MB
max_stack_depth = 4MB
dynamic_shared_memory_type = posix
archive_mode = on
max_wal_senders = 10
wal_sender_timeout = 0
min_wal_size = 4GB
max_wal_size = 16GB
wal_level = logical
checkpoint_timeout = 15min
checkpoint_completion_target = 0.9
In my sysct.conf I have:
vm.overcommit_memory=2
vm.overcommit_ratio=50
vm.vfs_cache_pressure=50
vm.dirty_background_ratio=10
vm.dirty_ratio=40
fs.nr_open=10000000
fs.file-max=10000000
vm.nr_hugepages=980
vm.hugetlb_shm_group=1010
my huge meminfo looks:
cat /proc/meminfo | grep -i huge
AnonHugePages: 0 kB
ShmemHugePages: 0 kB
FileHugePages: 0 kB
HugePages_Total: 980
HugePages_Free: 980
HugePages_Rsvd: 0
HugePages_Surp: 0
Hugepagesize: 2048 kB
Hugetlb: 2007040 kB
When I start postgres instance I get error:
May 07 10:56:32 pg1 pg_ctl[16753]: server starting
May 07 10:56:32 pg1 systemd[1]: Started postgres-17.4-local.service - PostgreSQL 17.4 database local server.
May 07 10:56:35 pg1 pg_ctl[16756]: 2025-05-07 10:56:35.826 CEST [16756] - [ - - ] [] : XX000FATAL: could not map anonymous shared memory: Cannot allocate memory
May 07 10:56:35 pg1 pg_ctl[16756]: 2025-05-07 10:56:35.826 CEST [16756] - [ - - ] [] : XX000HINT: This error usually means that PostgreSQL's request for a shared memory segment exceeded available memory, swap space, or huge pages. To reduce the request size (currently 2204106752 bytes), reduce PostgreSQL's shared memory usage, perhaps by reducing "shared_buffers" or "max_connections".
May 07 10:56:35 pg1 pg_ctl[16756]: 2025-05-07 10:56:35.826 CEST [16756] - [ - - ] [] : 00000LOG: database system is shut down
May 07 10:56:35 pg1 systemd[1]: postgres-17.4-sdx.service: Main process exited, code=exited, status=1/FAILURE
May 07 10:56:35 pg1 systemd[1]: postgres-17.4-sdx.service: Failed with result 'exit-code'.
May 07 10:56:35 pg1 systemd[1]: postgres-17.4-sdx.service: Consumed 3.493s CPU time, 2.8M memory peak, 0B memory swap peak.
When I comment #huge_pages=on in configuration postgresql started without problems.
Can someone tell me where is the problem?
Regards
Bogdan
