Time configuration and synchronization across Management modules, IOMs and iDRACs This technical white paper explains how to configure time on the management module and synchronize the time across MMs, IOMs, iDRACs, and NTP servers using Network time Protocol. It also explains the time synchronization mechanism between these modules for trouble shooting.
Revisions Revisions Date Description Jan 2019 Initial release Acknowledgements This paper was produced by the following members of the Dell EMC storage engineering team: Author: Santosh Athreya Shenoy and Irfan Azam The information in this publication is provided “as is.” Dell Inc. makes no representations or warranties of any kind with respect to the information in this publication, and specifically disclaims implied warranties of merchantability or fitness for a particular purpose.
Table of contents Table of contents Revisions.............................................................................................................................................................................2 Acknowledgements .............................................................................................................................................................2 Table of contents .................................................................................................
Executive summary Executive summary In Modern computer networks time synchronization is critical because every aspect of managing, securing and debugging a network involves determining when events happen. Time synchronization failures between modules can lead to undesired behavior. Using this feature we can achieve time synchronization within different modules of MM. We can also achieve time synchronization across different modules like MMs, IOMs, iDRACs and NTP server.
Date /Time settings and synchronization on MM • User manually configures time to go back in chassis by greater than 15 mins. User configures the management modules to synchronize to external servers and this causes the time to jump back greater than 15mins. If the MM is configured to synchronize to only one external NTP server and the server is inaccurate, it can cause MM time to be configured incorrectly. NTP documentation requires user to configure at least 3 sources for NTP clients to work as expected.
Configure Management module to synchronize to NTP server 4. Provide Primary NTP server address and/or Secondary NTP server address and/or Tertiary NTP server address and select Apply. Case 1: Only Primary NTP server address provided. NTP takes the available sources of time and submits their timing data to intersection and clustering algorithms, looking for the best idea of the correct time.
Configure iDRAC and SAS IOMs to synchronize to Management Module Note: Either one or more NTP servers are provided, if Management Module is not able to reach any of them or the servers are not valid NTP servers, or their time is not in-sync to each other, the Management Module may still syncing to the local clock. The time source value will show local clock in that case.
Best practices for NTP configuration Best practices for NTP configuration • • • • • • 8 Use enough time sources: NTP takes the available sources of time and submits their timing data to intersection and clustering algorithms, looking for the best idea of the correct time. If there is only 1 source of time, the answer is obvious. It may not be a good source of time, but it's the only one. If there are 2 sources of time and they agree well enough, that's good.
