We use Xubuntu 14.04 64-bit with modern fat clients (Intel Ivy Bridge) on a gigabit LAN. Fat clients have 2 GB RAM each, with around 1600 MB available after the onboard graphics allocation.
We have NBD swap enabled (8 GB) and we have quite a few users who regularly spill over into swap space, despite swappiness being set to 10. We are getting frequent very long pauses / halts of fat clients which are swapping, eventually requiring reboots for those users. Affected users reboot 1 - 2 times per day because of this. I feel something is going wrong with NBD swap. We never had this issue on much less powerful fat clients (7 year old Athlons) on Xubuntu 12.04 32-bit, mostly with 1GB RAM, some with 2 GB RAM. When this happens: - nbd-client CPU usage is very high. - There is a steady stream of data being sent from the server to the client - presumably this is the requested swap, but it goes on for too long at too high a rate to be reasonable - if it's sending 30+ megabytes / sec for 90+ seconds, that's 2.7 GB transferred when TOTAL swap used is only 800 MB. I don't know how this works, but that doesn't seem to make sense to me. - If machines are left in peace for long enough (a number of minutes) they usually recover, but the next action (like switching browser tabs) brings on the same behaviour. From a user's perspective, the system has "crashed" and they reboot. Here's a screenshot of the client's htop and server's bmon during such an instance: http://i.imgur.com/29MRnvT.png In this case it's just a VM fat client with 1 GB RAM, but it's the same for real fat clients with more memory. Any ideas what could be going wrong? Do we just need to throw more RAM at the clients? :( Side note: Modern browsers consume ridiculous amounts of memory on complex sites like Google Docs and Office 365 - in excess of 400 MB with just a handful of tabs open is not unusual for us. Normal? ------------------------------------------------------------------------------ Slashdot TV. Video for Nerds. Stuff that matters. http://tv.slashdot.org/ _____________________________________________________________________ Ltsp-discuss mailing list. To un-subscribe, or change prefs, goto: https://lists.sourceforge.net/lists/listinfo/ltsp-discuss For additional LTSP help, try #ltsp channel on irc.freenode.net
