Postgres fails to start due to too large a shared memory setting

[tomhughes]

On a machine with 128Gb of RAM chef is configuring postgres for 32Gb of shared memory, in /var/opt/opscode/postgresql/9.2/data/postgresql.conf:

shared_buffers = 32228MB # min 128kB

but it has only configured the kernel for 16Gb of shared memory, in /etc/sysctl.d/90-postgresql.conf:

#
# opscode private chef postgresql kernel shm tweaks
#
kernel.shmmax = 17179869184
kernel.shmall = 4194304

Postgres then fails to start, and the upgrade from chef server 11 fails a a result.

This looks like it may be a return of https://tickets.opscode.com/browse/CHEF-3889?

[yinym]

It seems that current Chef server 12 embedded private_chef cookbook did not fix this issue.

In https://github.com/chef/chef-server/blob/master/omnibus/files/private-chef-cookbooks/private-chef/attributes/default.rb#L410, the shmmax has been set to 17179869184, which is the value of 16GB in bytes.

However, in the following logic to calculate shared_buffer from line 424 - line 432:

quarter_mem = node['memory']['total'].to_i/4
postgres_max_mem = [0.85*node['private_chef']['postgresql']['shmmax'],
                    node['private_chef']['postgresql']['shmmax'] - 2*BYTES_IN_GIG].min
if(quarter_mem > postgres_max_mem)
  shared_bytes = postgres_max_mem
else
  shared_bytes = quarter_mem
end
default['private_chef']['postgresql']['shared_buffers'] = "#{shared_bytes/1024}MB"

It is actually treating this node['private_chef']['postgresql']['shmmax'] value with kB unit. In https://github.com/chef/chef-server/blob/master/omnibus/files/private-chef-cookbooks/private-chef/attributes/default.rb#L7, the value for BYTES_IN_GIG is actually in kB. node['memory']['total'] is in kB as well. So this logic will use set the shared_buffer to system memory/4 value even if this value is over the 16GB limit. (In this wrong logic, the actual limit is 16TB!).

But this can still be covered if the block in https://github.com/chef/chef-server/blob/master/omnibus/files/private-chef-cookbooks/private-chef/recipes/postgresql.rb#L68 did not put 16GB limit sysctl.

[kramvan1]

BYTES_IN_GIG = 1048576 just a bit off....maybe closer to 1073741824?

[stevendanna]

This is being worked on here: #309

[stevendanna]

It appears #309 has been merged, so I'm going to close this one out.