| Gavin W. Burris on 18 Apr 2016 09:36:44 -0700 |
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| Re: [PLUG] >32K concurrent processes |
Hi, Bhaskar. AH, OK. I should have asked, "What are you trying to accomplish?" Don't run everything on one box! Scale horizontally, with at least two user-facing nodes. You want to engineer in redundancy from square-one. If you don't, there will be no ability to sanely handle critical patching/updates, or deal with scaling up. With Grid Engine, that would be two master hosts, and at least two compute nodes actually running the procs, all with an nfs shared cell directory; The secondary master is called the shadow master in Grid Engine-speak. Grid Engine would be a good solution if you need to run some existing command-line or batch code. If this is for web, strongly consider having a redundant API endpoint to run functions. A good way to do this would be with Docker and Swarm. Docker is a completely different approach, but one that is correct for scaling web applications. Cheers. On Mon 04/18/16 11:49AM EDT, K.S. Bhaskar wrote: > Thanks for the suggestions, Gavin, but batching the load won't work in this > case. We're trying to run a workload that simulates a large number of > concurrent users (as you might find at a large financial or healthcare > institution) all of whom expect the system to respond immediately when they > ask it to do something. I intend to play with the scheduler. > > Regards > -- Bhaskar > > > On Mon, Apr 18, 2016 at 9:13 AM, Gavin W. Burris <bug@wharton.upenn.edu> > wrote: > > > Good morning, Bhaskar. > > > > Have you considered using /dev/shm aka tmpfs for shared memory on Linux? > > Maybe stage all required files there and make sure you are read-only where > > possible. > > > > With so many processes, your system is just constantly changing threads. > > Assuming you are not oversubscribing RAM (32GB / 32k is less than 1MB per), > > you will want to tune the kernel scheduler. > > > > https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/html/Performance_Tuning_Guide/sect-Red_Hat_Enterprise_Linux-Performance_Tuning_Guide-CPU-Configuration_suggestions.html#sect-Red_Hat_Enterprise_Linux-Performance_Tuning_Guide-Configuration_suggestions-Tuning_scheduling_policy > > > > This very much sounds like an HPC problem (high-performance computing), so > > my initial reaction is why not use a resource manager tuned for > > high-throughput? Take a look at Open Grid Scheduler ( > > http://gridscheduler.sourceforge.net/), an open source version of Grid > > Engine. This will give you a layer of control, a job queue, where you > > could then do a task array. Maybe you could launch 1000 jobs that iterate > > 320 times? The job queue could then be tuned to not overload the system > > and keep the system maximally / optimally utilized, aka don't run > > everything at once but place it in a queue that runs through what you need > > as resources are available. I would strongly consider using Grid Engine, > > expecially given your statement that the procs "do a teeny bit of activity > > every 10 seconds." > > > > Cheers. > > > > On Sun 04/17/16 11:12AM EDT, K.S. Bhaskar wrote: > > > Thanks for the links Rohit. I'll check them out. The storage is SSD, the > > > processes do minimal IO - I'm just trying to establish the ability to > > have > > > a file open by more than 32K processes, and I'm clearly running into a > > > system limit. This is a development machine (16 cores, 32GB RAM - the > > > production machine has something like 64 cores and 512GB RAM), but I > > can't > > > get you access to poke around because it is inside a corporate network. > > > > > > However, as the software is all open source, I can easily help you get > > set > > > up to poke around using your own system, if you want. Please let me know. > > > > > > Regards > > > -- Bhaskar > > > > > > > > > On Sun, Apr 17, 2016 at 10:54 AM, Rohit Mehta <ro@paper-mill.com> wrote: > > > > > > > Some kernel parameters to research (which may not be right for your > > > > application) > > > > > > > > > > https://www.debian-administration.org/article/656/Installing_Oracle11_and_Oracle12_on_Debian_Wheezy_Squeeze > > > > and /etc/security.conf changes > > > > > > http://stackoverflow.com/questions/9361816/maximum-number-of-processes-in-linux > > > > > > > > Do these process do a lot of IO? Is your storage rotational media or > > > > SSD? Can your application run off ramdisk storage? Have you tried > > > > enabling hyperthreading? > > > > > > > > Do you have the ability to test application loads non-production > > system? > > > > If so i'd be interesting in helping you poke around. It might be an > > > > education for me. > > > > > > > > > > > > On Sun, Apr 17, 2016 at 10:42 AM, Rohit Mehta <ro@paper-mill.com> > > wrote: > > > > > > > >> Back many years ago, I installed Oracle on my Debian workstation for > > fun, > > > >> and I remember the guide had a lot of tweaks. "ulimit" is one that I > > can > > > >> think of, but I don't remember them all. I'm poking around the > > internet to > > > >> see if I can find the oracle guide (although it might not be relevant > > on > > > >> newer kernels) > > > >> > > > >> On Sun, Apr 17, 2016 at 10:27 AM, K.S. Bhaskar <bhaskar@bhaskars.com> > > > >> wrote: > > > >> > > > >>> Thanks Steve, but in this case we have a customer need to crank up > > the > > > >>> number of processes on Linux. > > > >>> > > > >>> Regards > > > >>> -- Bhaskar > > > >>> > > > >>> On Sat, Apr 16, 2016 at 4:09 PM, Steve Litt < > > slitt@troubleshooters.com> > > > >>> wrote: > > > >>> > > > >>>> On Fri, 15 Apr 2016 17:40:09 -0400 > > > >>>> "K.S. Bhaskar" <bhaskar@bhaskars.com> wrote: > > > >>>> > > > >>>> > I am trying to crank up more than 32K concurrent processes (the > > > >>>> > processes themselves hang and do a teeny bit of activity every 10 > > > >>>> > seconds). But the OS (64-bit Debian 8 - Jessie) stubbornly > > refuses to > > > >>>> > crank up beyond 32K-ish processes. pid_max is set to a very large > > > >>>> > number (1M), so that's not it. Any suggestions on what limits to > > look > > > >>>> > for appreciated. Thank you very much. > > > >>>> > > > >>>> This is old information, but back in the day people who wanted lots > > and > > > >>>> lots of processes used one of the BSDs to host that server. > > > >>>> > > > >>>> SteveT > > > >>>> > > > >>>> Steve Litt > > > >>>> April 2016 featured book: Rapid Learning for the 21st Century > > > >>>> http://www.troubleshooters.com/rl21 > > > >>>> > > > >>>> > > ___________________________________________________________________________ > > > >>>> Philadelphia Linux Users Group -- > > > >>>> http://www.phillylinux.org > > > >>>> Announcements - > > > >>>> http://lists.phillylinux.org/mailman/listinfo/plug-announce > > > >>>> General Discussion -- > > > >>>> http://lists.phillylinux.org/mailman/listinfo/plug > > > >>>> > > > >>> > > > >>> > > > >>> > > > >>> > > ___________________________________________________________________________ > > > >>> Philadelphia Linux Users Group -- > > > >>> http://www.phillylinux.org > > > >>> Announcements - > > > >>> http://lists.phillylinux.org/mailman/listinfo/plug-announce > > > >>> General Discussion -- > > > >>> http://lists.phillylinux.org/mailman/listinfo/plug > > > >>> > > > >>> > > > >> > > > > > > > > > > ___________________________________________________________________________ > > > > Philadelphia Linux Users Group -- > > > > http://www.phillylinux.org > > > > Announcements - > > > > http://lists.phillylinux.org/mailman/listinfo/plug-announce > > > > General Discussion -- > > > > http://lists.phillylinux.org/mailman/listinfo/plug > > > > > > > > > > > > > > > ___________________________________________________________________________ > > > Philadelphia Linux Users Group -- > > http://www.phillylinux.org > > > Announcements - > > http://lists.phillylinux.org/mailman/listinfo/plug-announce > > > General Discussion -- > > http://lists.phillylinux.org/mailman/listinfo/plug > > > > > > -- > > Gavin W. Burris > > Senior Project Leader for Research Computing > > The Wharton School > > University of Pennsylvania > > Search our documentation: http://research-it.wharton.upenn.edu/about/ > > Subscribe to the Newsletter: http://whr.tn/ResearchNewsletterSubscribe > > ___________________________________________________________________________ > > Philadelphia Linux Users Group -- > > http://www.phillylinux.org > > Announcements - > > http://lists.phillylinux.org/mailman/listinfo/plug-announce > > General Discussion -- > > http://lists.phillylinux.org/mailman/listinfo/plug > > > ___________________________________________________________________________ > Philadelphia Linux Users Group -- http://www.phillylinux.org > Announcements - http://lists.phillylinux.org/mailman/listinfo/plug-announce > General Discussion -- http://lists.phillylinux.org/mailman/listinfo/plug -- Gavin W. Burris Senior Project Leader for Research Computing The Wharton School University of Pennsylvania Search our documentation: http://research-it.wharton.upenn.edu/about/ Subscribe to the Newsletter: http://whr.tn/ResearchNewsletterSubscribe ___________________________________________________________________________ Philadelphia Linux Users Group -- http://www.phillylinux.org Announcements - http://lists.phillylinux.org/mailman/listinfo/plug-announce General Discussion -- http://lists.phillylinux.org/mailman/listinfo/plug