[R] Memory limit on Linux?

[Stackpole, Chris]

> From: Kevin E. Thorpe [mailto:kevin.thorpe at utoronto.ca] 
> Sent: Monday, August 12, 2013 11:00 AM
> Subject: Re: [R] Memory limit on Linux?
>
> What does "ulimit -a" report on both of these machines?

Greetings,
Sorry for the delay. Other fires demanded more attention...

For the system in which memory seems to allocate as needed:
$ ulimit -a
core file size          (blocks, -c) 0
data seg size           (kbytes, -d) unlimited
scheduling priority             (-e) 0
file size               (blocks, -f) unlimited
pending signals                 (-i) 386251
max locked memory       (kbytes, -l) 32
max memory size         (kbytes, -m) unlimited
open files                      (-n) 1024
pipe size            (512 bytes, -p) 8
POSIX message queues     (bytes, -q) 819200
real-time priority              (-r) 0
stack size              (kbytes, -s) 10240
cpu time               (seconds, -t) unlimited
max user processes              (-u) 386251
virtual memory          (kbytes, -v) unlimited
file locks                      (-x) unlimited 

For the system in which memory seems to hang around 5-7GB:
$ ulimit -a
core file size          (blocks, -c) 0
data seg size           (kbytes, -d) unlimited
scheduling priority             (-e) 0
file size               (blocks, -f) unlimited
pending signals                 (-i) 2066497
max locked memory       (kbytes, -l) 64
max memory size         (kbytes, -m) unlimited
open files                      (-n) 1024
pipe size            (512 bytes, -p) 8
POSIX message queues     (bytes, -q) 819200
real-time priority              (-r) 0
stack size              (kbytes, -s) unlimited
cpu time               (seconds, -t) unlimited
max user processes              (-u) 1024
virtual memory          (kbytes, -v) unlimited
file locks                      (-x) unlimited

I can also confirm the same behavior on a Scientific Linux system though the "difference" besides CentOS/RHEL is that the Scientific is at an earlier version of 6 (6.2 to be exact). The Scientific system has the same ulimit configuration as the problem box.

I could be mistaken, but here are the differences I see in the ulimits:
pending signals: shouldn't matter
max locked memory: The Scientific/CentOS system is higher so I don't think this is it.
stack size: Again, higher on Scientific/CentOS.
max user processes: Seems high to me, but I don't see how this is capping a memory limit.

Am I missing something? Any help is greatly appreciated. 
Thank you!

Chris Stackpole