For those of you running notebook servers in "production", inside a VM, here are some questions about configuration. I'm particularly interested in sagenb.org.
1. what VM you are using? 2. How much physical memory you give to the VM? virtual cpus? 3. Do you add swap inside the VM? How much? 4. What's the ulimit you use for the notebook? 5. Who are your users? Here are the answers for my server 1. using KVM-72 from debian lenny (stable) --- using virtio for disk and network (makes a huge difference). The host is core 2 quad with 8Gb ram. 2. for the guest VM I assign 2Gb / 2 virtual cpu. 3. I set the VM with no swap; should I? 4. ulimit='-u 100 -v 300000 -t 3600' 5. There are about 15 students taking a sage course I'm teaching this semester (started 2 weeks ago); the server is also meant to support other people in the math department, but I'm just starting to convince people to try it, so usage is probably light for now. I had a few OOM incidents in the console of the VM, namely python got killed 4 times and lisp.run 1 time in the 9 days of uptime of the VM. I'm concerned because the notebook hangs on me often, in front of the class; it always seems to be related to symbolic expressions, e.g. after running other symbolic expressions, it may get hang on the seemingly innocent "latex(sin(pi/3))". It hangs such that "Interrupt" doesn't work -- restarting the worksheet sometimes works and sometimes doesn't. It always "works" to quit the worksheet, stop it from the home, and reopening. These incidents are completely unrelated to the OOM incidents. The same worksheet that hangs in my server often, doesn't seem to hang in sagenb.org, so it may be a misconfiguration on my part. --- WRT swap space in the guest VM: my reasoning is that I/O on the guest must be slow, so if more memory is needed, it should be better to assign more memory to the guest, and add swap to the host. But there may be a fallacy on that reasoning (such as: the guest vm abusing the memory for caching, etc) Any opinions? Gonzalo --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-devel@googlegroups.com To unsubscribe from this group, send email to sage-devel-unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
