Using STP to set clock for zVM LPAR. zVM and zLinux guest show time, both in sync. Trying to avoid setting up NTPD and starting on all zLinux if not necessary.
Came about due to checks comparing zLinux software configuration vs X86 configuration, they run NTPD. So, I was asked to do same. Never seen an issue with time under zLinux. Thank you for your assistance Joe Joseph Vitale Technology Services Group Mainframe Operating Systems Pershing Plaza 95 Christopher Columbus Drive Floor 14 Jersey City, N.J. 07302 Work 201-395-1509 Cell 917-903-0102 -----Original Message----- From: Linux on 390 Port [mailto:LINUX-390@VM.MARIST.EDU] On Behalf Of Rob van der Heij Sent: Wednesday, March 18, 2015 3:54 PM To: LINUX-390@VM.MARIST.EDU Subject: Re: Network Time Protocol Daemon needed for zLinux? On 18 March 2015 at 20:04, Vitale, Joseph <joseph.vit...@bnymellon.com> wrote: > My Linux runs under zVM, not in a stand alone LPAR. So, NTP or STP > not required, correct ? > That depends on whether you have STP steer the clock for the LPARs. It's a priced feature. If Q TIME on z/VM is now very accurate, then you're most likely steering and your Linux guests will follow. When z/VM is not running on time, then all Linux guests will get a clock (the same) that is slightly off as well. If that bothers you (your applications rather) then you can either implement STP or have each guest synchronize it's won clock with ntpd etc. If you frequently reboot, then ntpdate during startup might be enough to stay somewhat on time (eg 3 seconds per week). Some things like Kerberos expect you to be sort-of on time (10's of seconds, iirc). My experience is that the quality of the clock with ntpd is somewhat less, but that's a moot point when it's your only option. Yes, it's true that running ntpd takes resources. But much middleware does too and we're not on G3 anymore. PS Yes, I did do an "ntpq" for CMS a while back, but the year does not have nearly enough Friday nights to come up with an alternative for STP. Rob ---------------------------------------------------------------------- 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/ The information contained in this e-mail, and any attachment, is confidential and is intended solely for the use of the intended recipient. Access, copying or re-use of the e-mail or any attachment, or any information contained therein, by any other person is not authorized. If you are not the intended recipient please return the e-mail to the sender and delete it from your computer. Although we attempt to sweep e-mail and attachments for viruses, we do not guarantee that either are virus-free and accept no liability for any damage sustained as a result of viruses. Please refer to http://disclaimer.bnymellon.com/eu.htm for certain disclosures relating to European legal entities. ---------------------------------------------------------------------- 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/
