Fog Project Documentation (FOG Docs)

Display Timezone

Properties3
descriptionhow FOG decides which timezone to show dates and times in, how each user can choose their own, and why that is separate from the timezone the database is written in
tagsmanagement, web-management, web-ui
aliasesDisplay Timezone, Timezone, Time Zone, FOG_TZ_INFO

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Display Timezone

FOG shows every date and time in a timezone. Which one depends on two settings that are easy to confuse, so it is worth being clear about both.

The install’s timezone

FOG_TZ_INFO, under FOG Configuration → FOG Settings, is the timezone the server itself works in. It is the default everyone sees — the zone a user who has never chosen one of their own gets.

It used to be more than that. On older versions it was also the zone FOG wrote into the database, so changing it did not re-present the times already recorded, it changed what those recorded times were taken to mean. FOG now writes UTC, and FOG_TZ_INFO no longer has any bearing on what is stored.

!!! warning “Changing FOG_TZ_INFO still re-labels the older records” Dates written before your server moved to UTC were written in whichever zone FOG_TZ_INFO named at the time, and that is still how they are read. Changing the setting therefore changes how those older dates are interpreted, though not how anything written since is. Nothing is rewritten, and nothing warns you.

Those older dates are marked on screen — see
[[unadjusted-timestamps|Timestamps Before the UTC Change]].

If you only want people to *see* a different timezone, that is the per-user
setting below, and it is the one you almost certainly want.

Your own timezone

Click the clock icon in the top bar. Choose a timezone and save; the page reloads and every date on it is now shown in the zone you picked.

This changes only what you see. It does not change anything that is stored, and it does not affect anyone else — two people looking at the same host see the same moment, each in their own zone.

The choice is saved against your user account rather than your browser, so it follows you to another machine. Choosing Server default clears it and puts you back on FOG_TZ_INFO.

Every signed-in user can set this, including an account with no role assigned.

What it covers

  • dates on any list — tasks, hosts, images, snapins, the audit log
  • dates on edit and detail pages
  • filtering by date. If you filter a list to “on 29 August”, that means your 29 August. This matters more than it sounds: near midnight the server’s day and yours are different days, and a filter that showed one and searched the other would look like missing rows.

What it does not cover

The REST API. Dates from /api/… come back exactly as stored — UTC — whichever user’s token was used, and with no timezone marker on the value. A script needs one stable answer, not one that changes depending on who is running it. Rows written before this server moved to UTC are the exception the API cannot signal; see Timestamps Before the UTC Change.

Scheduled tasks. A task set to run at 02:00 runs at 02:00 on the server. The schedule is the server’s clock, not the viewer’s, and changing your display timezone does not move it.

What is stored

FOG stores times in UTC. Your upgrade recorded the instant it started doing so, and it did not convert anything that was already there — a conversion is one-way and there was no reliable way to know which clock had written any given old row. So dates on either side of that instant are read differently, and the older ones are marked where they appear: Timestamps Before the UTC Change.

The per-user setting above is unaffected either way. It has only ever decided what you are shown.

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