Postgres shared memory error

All;

I just want to be sure that I'm not causing myself greif. I have a kvm
in the cloud that is supposed to have access to 32GB of ram. when I do a
top I only see 1GB of ram, I've pinged the hosting provider, maybe it
shows up as it's used?

Anyway when I try and start postgres I see this:
/
$ 2012-04-28 12:00:33 EDT [6429]: [1-1] FATAL: XX000: could not
create shared memory segment: Cannot allocate memory
2012-04-28 12:00:33 EDT [6429]: [2-1] DETAIL: Failed system call was
shmget(key=5432001, size=7700914176, 03600).
2012-04-28 12:00:33 EDT [6429]: [3-1] HINT: This error usually means
that PostgreSQL's request for a shared memory segment exceeded available
memory or swap space. To reduce the request size (currently 7700914176
bytes), reduce PostgreSQL's shared_buffers parameter (currently 917504)
and/or its max_connections parameter (currently 503).
The PostgreSQL documentation contains more information about
shared memory configuration.
2012-04-28 12:00:33 EDT [6429]: [4-1] LOCATION:
InternalIpcMemoryCreate, pg_shmem.c:178 /

Which means I should bump up shmmax like this:

/# sysctl -w kernel.shmmax=7700914176/

and add it to /etc/sysctl.conf:

/# tail /etc/sysctl.conf
kernel.msgmax = 65536

# Controls the maximum shared segment size, in bytes
kernel.shmmax = 68719476736

# Controls the maximum number of shared memory segments, in pages
kernel.shmall = 4294967296

#PostgreSQL
kernel.shmmax = 7700914176 /

I assume I should have to tweak ONLY kernel.shmmax, am I correct?
I'm also assuming that this is a KVM cloud host provider issue, i.e. it
looks like I actually do not have 32G or ram. Does anyone disagree with
my conclusions?

Thanks in advance