Thanks Sirs Richard, John, DavidB, Rob, DavidD, Bear, Thomas, Patrick and Madame Marcy -
I appreciate your input very much! I believe it has helped decide in favor implementing ntpd on Linux guests in this particular instance. A special thanks to Rob for his presentation which helped myself and others understand the science behind it for the case of z/VM and it's pengins... Scott Rohling On Tue, Jun 5, 2012 at 8:33 AM, Patrick Spinler <spinler.patr...@mayo.edu>wrote: > I'd suspect that just running ntpd would be a preferably option here. > Otherwise, you will get a cron awakened activity / network peak as > dozens or hundreds of servers all wake up and try to sync their time. > > ntpd really is a very low impact service to run, both in terms of > network and server resources. > > -- Pat > > On 06/04/2012 06:36 PM, Thomas Kern wrote: > > When we had linux on Z, we ran the ntpdate program once per day (before > start of > > business). On our current ESX and Oracle Virtualization (xen), we need > to run it every hour. > > > > /Tom Kern > > > > On 6/4/2012 12:31, David Boyes wrote: > >> Running NTP everywhere wakes every guest up periodically, so you waste > a fair amount of cycles waking up to do nothing for most guests. > >> > >> The clocks in Linux guests do drift slightly (even if the HW is synced > to STP) -- it's order of tenths of microseconds, but it does lose a little > (barely measurable) bit. > >> > >> The things that really care about time (like any service using Kerberos > security, or other things that use time as a salt in some other process) > need NTP because they don't work without completely accurate time. > >> Everything else can get along fine with running ntpdate once a day. > > > > ---------------------------------------------------------------------- > > For LINUX-390 subscribe / signoff / archive access instructions, > > send email to lists...@vm.marist.edu with the message: INFO LINUX-390 > or visit > > http://www.marist.edu/htbin/wlvindex?LINUX-390 > > ---------------------------------------------------------------------- > > For more information on Linux on System z, visit > > http://wiki.linuxvm.org/ > > ---------------------------------------------------------------------- > For LINUX-390 subscribe / signoff / archive access instructions, > send email to lists...@vm.marist.edu with the message: INFO LINUX-390 or > visit > http://www.marist.edu/htbin/wlvindex?LINUX-390 > ---------------------------------------------------------------------- > For more information on Linux on System z, visit > http://wiki.linuxvm.org/ > ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to lists...@vm.marist.edu with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390 ---------------------------------------------------------------------- For more information on Linux on System z, visit http://wiki.linuxvm.org/
