The Migration, Marshaled
A cutover is scheduled for Saturday and half the team wants to flip it all at once. Echo loves the clean switch. Root walks the rollback path, the fallback DNS, the people who'll be awake — because the move you can't undo isn't a plan, it's a bet.
A migration is a campaign. You move the supply lines before you move the men.
The cutover was Saturday, and half the team wanted to do it in one move: flip the new system on at midnight, flip the old one off, go home heroes.
Echo was, to Root's mild surprise, on the cautious side for once — but even she was getting swept up. "It's cleaner. One switch. No running both, no sync, no weird in-between. Rip the bandage."
"Show me the runbook." She did. One page. It said, essentially, flip the switch. "Where's the part where it goes wrong."
"It won't—"
"Where's the part where it goes wrong." He didn't raise his voice. "An army that marches out of order loses before it meets the enemy. I don't care how good the new system is. I care what happens at 12:40 when the thing you didn't think of shows up — because at 12:40 it's just you, and whoever's still awake, and a decision you can't take back."
So they built the real plan. The rollback path: how to get the old system back, exactly, in under five minutes — tested in advance, not hoped for. The fallback DNS, pre-staged. The list of who would actually be awake, with phone numbers, and who would make the call to abort, named, so it wasn't decided by six tired people at once. The order of operations, written so a stranger could run it.
"This is four pages now," Echo said. "And most of it is for things that probably won't happen."
"Most of an army is supply lines for a battle that mostly goes to plan. You move the supply lines first anyway, because the one time it doesn't go to plan, they're the difference between a bad night and a bad quarter." Root tapped the abort criteria. "This is the most important page. The brave part of a migration isn't the flip. It's deciding, in advance and in daylight, what would make you turn the whole thing around — so that at 12:40 you're following an order instead of having an opinion."
"Big bang adoption" — switching everyone to the new system at a single stroke — is the cheapest changeover and, when it fails, the one that puts the whole organization in trouble at once; the alternatives (phased and parallel adoption) trade speed for a road back. Treated as "just flip the switch," the big bang becomes a legend for the wrong reason. The work that makes it survivable is logistical and mostly invisible: a tested rollback, pre-staged fallbacks, a named decision-maker, explicit abort criteria, an ordered runbook a stranger could run. Like a campaign, it's won in the supply lines and the discipline of setting out in order — not in the bravery of the final move.
Inspired by Big bang adoption.
An army must set forth in proper order. If discipline breaks down at the start, the entire campaign fails. A just cause and valid orders are non-negotiable foundations.
The figure. ䷆ The Army (Shī), line 1 changing → ䷒ Approach (Lín). "An army must set forth in proper order. If discipline breaks down at the start, the entire campaign fails." A just cause and valid orders are the non-negotiable foundation — everything that follows depends on the order in which you begin.
The reading. The brave part of a migration isn't the flip; it's deciding in daylight what would make you turn the whole thing around. Move the supply lines — rollback, fallback, the named abort call — before you move the men.
Department: IT (機)