On 6. Feb 2012, at 20:29 , Doug Barton wrote: > Howdy, > > Thinking about implementing a poor-man's virtualization solution with > lots'o'jails, and wondering what people think about the practical limits > of such a system. I realize that part of the answer is going to depend > on CPU and RAM, so let's assume for the sake of argument that the answer > to that bit is, "Lots of both." > > So first question is, is there some sort of hard-coded limit somewhere? > If not, what is the largest number of jails that you've created > successfully/reliably on a system, and what are the specs for that system?
Yes, jails provide you 6 9s ... though that's not 99.9999% but 999999 is the maximum number of jails. And yes, I have started this many before -- without processes or anything. It took a couple of days, due to some list handling, which could be optimized. You will find that once you get there, you'll have a syscall which never returns... You notice once the start loop slows down if you print a . every 100 or 1000. The machine was a 4 or 8 core amd64 with 8G of memory. I think I had a slide in there: http://www.bsdcan.org/2010/schedule/attachments/130_2010-bz-the-new-vvorld.pdf I know if using vnets; you can get the 4k (or more) but I also have reports that it may not scale. The other limit you'll run into is the number of PIDs. And eventually scheduling depending on what you want to do. > And finally, has anyone run into trouble with a large number of IP > addresses for the jails? ISTR that way back when, the IP addresses > associated with a particular interface were stored in a linked list, so > as you added more you would start seeing O(N) slowdown on a lot of > network stuff in the kernel. Yeah, we still do list walks here and there. /bz -- Bjoern A. Zeeb You have to have visions! It does not matter how good you are. It matters what good you do! _______________________________________________ freebsd-jail@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-jail To unsubscribe, send any mail to "freebsd-jail-unsubscr...@freebsd.org"