On Mon, Oct 8, 2018 at 1:30 AM paralleluser <[email protected]> wrote:
> I decided to re-read the GNU parallel man page in full and found two > interesting paragraphs. Let us assume a single user machine where the user > has root access. It is the goal of the user to not limit himself in terms of > the number of jobs parallel can spawn (ie: full power to parallel). : > Overall Analysis: Do I care about anything with "ulimit" if I make the > changes above? Is there anything else to do to give parallel freedom to go > to the max? There are two limits that limit the number of jobs to run in parallel: Number of processes and number of file handles. The limits are set in different places. The system wide limits are set in /proc/sys/kernel/pid_max and /proc/sys/fs/file-max # This is the max on my system: echo 4194303 | sudo tee /proc/sys/fs/pid_max echo 18446744073709551615 | sudo tee /proc/sys/fs/file-max The maximums for the user are set in /etc/security/limits.conf and will only make sense if they are lower than the system wide limits. The format of /etc/security/limits.conf is described in the comments in that file. This is the max limits on my system: * soft nofile 1048576 * hard nofile 1048576 * soft nproc 4194303 * hard nproc 4194303 If you find a way to raise the 1048576 please post an answer on https://unix.stackexchange.com/questions/359189/fixing-ulimit-open-files-cannot-modify-limit-operation-not-permitted/359418#359418 /Ole
