Resolving snapshot issues when Daylight Saving (DST) adjustment is disabled in Windows (KBA7856)

Issue

In cases where Windows servers are used as Source or Target Environments for a Delphix Engine, and the Windows setting Adjust for daylight saving time automatically is disabled, some issues may occur when taking dSource or VDB snapshots.

Known issues include:

• dSource Backups using third party backup providers such as NetBackup may fail during Daylight Saving Time
  • NetBackup snapshots may fail with the error exception.db.mssqlldb.source.netbackup.bplist.query.failed, due to the Netbackup error EXIT STATUS 20: invalid command parameter.
• The timestamp of any successful snapshots taking during Daylight Saving Time may be incorrectly shifted by one hour

Applicable Delphix Versions

Click here to view the versions of the Delphix engine to which this article applies

Major Release	All Sub Releases
6.0	6.0.0.0, 6.0.1.0, 6.0.1.1, 6.0.2.0, 6.0.2.1, 6.0.3.0, 6.0.3.1, 6.0.4.0, 6.0.4.1, 6.0.4.2, 6.0.5.0, 6.0.6.0, 6.0.6.1, 6.0.7.0, 6.0.8.0, 6.0.8.1
5.3	5.3.0.0, 5.3.0.1, 5.3.0.2, 5.3.0.3, 5.3.1.0, 5.3.1.1, 5.3.1.2, 5.3.2.0, 5.3.3.0, 5.3.3.1, 5.3.4.0, 5.3.5.0, 5.3.6.0, 5.3.7.0, 5.3.7.1, 5.3.8.0, 5.3.8.1, 5.3.9.0
5.2	5.2.2.0, 5.2.2.1, 5.2.3.0, 5.2.4.0, 5.2.5.0, 5.2.5.1, 5.2.6.0, 5.2.6.1
5.1	5.1.0.0, 5.1.1.0, 5.1.2.0, 5.1.3.0, 5.1.4.0, 5.1.5.0, 5.1.5.1, 5.1.6.0, 5.1.7.0, 5.1.8.0, 5.1.8.1, 5.1.9.0, 5.1.10.0
5.0	5.0.1.0, 5.0.1.1, 5.0.2.0, 5.0.2.1, 5.0.2.2, 5.0.2.3, 5.0.3.0, 5.0.3.1, 5.0.4.0, 5.0.4.1, 5.0.5.0, 5.0.5.1, 5.0.5.2, 5.0.5.3, 5.0.5.4

Cause

When a Windows Environment is added or refreshed, the Delphix Engine correlates the configured Windows time zone to a Java time zone.

In current versions of the Delphix Engine, this correlation does not take into account the Windows Date & Time setting Adjust for daylight saving time automatically.

As a result, the Delphix Engine will assume that any times reported by the Windows host are adjusted for Daylight Saving Time (DST), even though they are not.

Resolution

To ensure snapshots are taken and reported with the correct timestamps, the Windows server should be adjusted to either:

• Enable the Adjust for daylight saving time automatically setting; or
• Set the time zone to an equivalent time zone that does not observe Daylight Saving time

 

Important:

After this setting is changed on the Windows host, the Environment must be Refreshed from the Delphix Engine Manage → Environments screen, to ensure that the updated time zone is detected.

 

Most time zones that observe Daylight Saving Time should have a corresponding time zone that does not use it. For example:

Daylight Saving Time enabled time zone	Equivalent time zone without DST
(UTC) Dublin, Edinburgh, Lisbon, London	(UTC) Coordinated Universal Time
(UTC-08:00) Pacific Time(US & Canada)	(UTC-08:00) Coordinated Universal Time - 08
(UTC+10:00) Canberra, Melbourne Sydney	(UTC+10:00) Brisbane

If the selected time zone does not observe Daylight Saving Time, the Adjust for daylight saving time option in Windows will automatically be grayed out.

A complete list of current Windows time zones may be unavailable if Windows Updates have not been applied to affected hosts.