클러스터 호스트를 제거한 후 VMM Pro 라이선스를 마이그레이션하는 방법

A VMM Pro license is activated on one Synology NAS, and the whole Virtual Machine Manager cluster borrows it from that host. That works until the day you remove the host the license lives on. The moment it leaves, every remaining host shows the VMM Pro license as Invalid with a 30-day countdown, even though the key itself is paid for and still has months left. This guide shows the fix we used on our own cluster on 18 October 2026: add the same key again on a host that stays, accept the migration, and the license moves across in about a minute. Every screenshot below comes from that run, with the license keys, account and serial number blurred out.

SynoPower Club 포인트: Our FlashStation FS2017 held the VMM Pro license for the cluster, but it is loud, so it only woke up at night to collect replicas and then went back to sleep. Once our DS1621xs+ and DS1525+ could protect each other, the FS2017 had no job left, and I removed it from the cluster. The console immediately turned orange: Invalid, 30 days remaining. There is no “transfer” button anywhere in Virtual Machine Manager. The fix turns out to be hiding behind the ordinary Add license button, and the dialog that confirms it is the only place Synology spells the move out. I recorded the whole thing so you do not have to guess.

What Happens to a VMM Pro license When Its Host Leaves the Cluster #

VMM Pro is sold as 3-node and 7-node packs, valid for one or three years and not refundable once activated. You activate the pack on one host, and that host carries it for every NAS in the same cluster. The license is tied to that host rather than to the cluster, so when the host is removed it takes the license with it into its own single-node cluster.

The hosts left behind keep the key in their license list, but its status changes to Activated in another cluster and Time Left reads Invalid. The summary panel switches to Invalid with 30 days remaining, and a link warns that some VMM Pro features will no longer be available after 30 days. Your virtual machines keep running during that grace period; nothing is shut down. The countdown is simply your deadline to put a valid license back.

Why We Removed the License Host From Our Cluster #

Our cluster used to have three members: a DS1621xs+ and a DS1525+ running production guests, and an FS2017 acting as a cold standby. The FS2017 held the 3-node VMM Pro license because it was the first host we activated. It powered on at night, accepted scheduled replicas from the other two, and powered off again. The full design is in our production cluster write-up.

Two things changed. The DS1525+ was upgraded to 64 GB of memory, and every protection plan was pointed at the other production host instead of the standby, so the DS1621xs+ and DS1525+ now replicate to each other. That made the FS2017 redundant, and since it is loud enough to hear from the next room, it was removed from the cluster. The only side effect was the license.

주인	전에	후에
FS2017	Cold standby, held the VMM Pro license	Removed from the cluster, license now Invalid
DS1621xs+	Production host	Production host, now holds the VMM Pro license
DS1525+	Production host	Production host and replication partner

Migrate or Buy Again: Your VMM Pro license Options #

When the license host leaves, there are three ways forward, and only one of them costs nothing:

• Migrate the same key. Add the key you already own on a host that stays. Synology recognises it is active elsewhere and offers to move it. Free, and the expiry date does not change. This is what this guide covers.
• Rejoin the old host. Add the removed host back to the cluster and the license is valid again. Useful as a rollback, but it defeats the purpose if you wanted that host gone.
• Activate a new pack. Only needed when the old key is expired, the cluster has grown past the pack size, or you want to move up from a 3-node to a 7-node pack. A new VMM Pro license pack starts a fresh term.

For a general answer on which Synology licenses can move between machines, see whether purchased Synology licenses can be transferred.

Move a VMM Pro license to Another Host in 4 Steps #

Run these steps in DSM on a host that will stay in the cluster and should carry the VMM Pro license from now on. We used the DS1621xs+. The host needs internet access, because the move is confirmed against the Synology license server.

Prefer to watch? This one-minute recording shows the whole migration on our DS1621xs+, from the Invalid warning to the old host losing the license.

What Each Screen in the Add License Wizard Means #

The wizard is the normal one for adding any license, so it helps to know which screens are routine and which one actually performs the move.

The agreement already hints at what happens next: a key can be applied to only one Synology NAS at a time, so adding it here must take it away from the FS2017.

After you click Next, a red warning says your current license is still valid and that adding a new license ends the current one, losing any remaining days. That message is generic and appears for any add. In our case we were adding the same key, and the term was not shortened: the expiry date after the move was exactly the one the FS2017 had shown.

The real decision is the next dialog. It names the NAS the key is activated on, with its serial number, and warns that if the original cluster has no other valid VMM Pro license, its Pro features will be disabled once you migrate. That is exactly what we wanted, so we clicked Migrate.

How the Old Host Reacts After the Migration #

Back on the summary page, the DS1621xs+ now shows the VMM Pro license as Normal with an expiry of 16 February 2027, and the key row reads Validated with 121 days left. The whole run, from clicking Add license to the green result, took just over a minute.

On the FS2017 the license page still showed Normal for a few seconds, then a notification popped up reading Invalid VMM Pro license, and its own panel switched to Invalid with the key marked Activated in another cluster. The roles had simply swapped.

Before You Remove a Host: A VMM Pro license Checklist #

Removing a host is the step that triggers all of this, so it is worth preparing for it. This is the checklist we worked through first:

• Move every running guest off the host, both its compute and its storage. A guest whose disks still live on a removed host cannot start anywhere else.
• Re-point protection plans that replicate to the host you are removing. Ours all targeted the standby, so each one was changed to replicate to the other production host and given a fresh full sync. Keep an independent copy as well; we export guests to Google Drive as described in our VMM backup guide.
• Check what the cluster needs afterwards. High availability needs at least three hosts, so a two-host cluster has to rely on replication and manual switchover instead.
• Have the Synology Account login ready, and make sure the host that will receive the VMM Pro license can reach the internet.
• Know the order. Remove the host first, then migrate. While the license host is still a member there is nothing to migrate, because the cluster already has a valid license.

What Changes in a Two-Host Cluster #

A 3-node VMM Pro license does not need three hosts. With two members it covers the cluster with one slot to spare, so the DS1525+ and DS1621xs+ keep every Pro feature they used before: live migration between them, protection plans with remote replication in both directions, and switchover when one of them needs maintenance.

We used exactly that the same day. Before the DS1525+ memory upgrade, every guest on it was switched over to the DS1621xs+ with only a few minutes of downtime each, and then moved back after the upgrade. The free edition of Virtual Machine Manager can also cluster hosts, but it cannot do this kind of replication and switchover; our comparison of Virtual Machine Manager and VMM Pro lists what needs the Pro license.

Synology에 대해 더 자세히 알아보려면 어디를 방문해야 할까요? #

These official Synology videos cover the cluster features the license unlocks:

VMM Pro license Migration Limits and Caveats #

The license follows its host, not the cluster. Whichever NAS you activate the key on carries it. If you plan to retire or power down a host, do not activate the key there in the first place, or plan to migrate it before that host goes.

The 30-day grace period is a deadline, not a free month. Guests keep running, but some Pro features stop working when it runs out. Migrate the key the same day you remove a host.

The old host loses Pro features too. After the move, the removed host shows Invalid. If it still runs guests that rely on replication or live migration, they lose those features unless it gets its own license.

The term does not restart. Migrating keeps the original expiry date. If you need more time, that is a renewal or a new pack, not a migration.

The same Synology Account is required. The wizard asks for the account that owns the key. A key bought for a client and registered to their account has to be moved while signed in to that account.

Never share the key in screenshots or tickets. The License page shows full keys, the account email and, in the migrate dialog, the serial number of the old host. Blur them before posting, as we did here.

참고문헌 #

• VMM Pro 라이선스 팩: official pack sizes, terms and the one-pack-per-cluster rule.
• Virtual Machine Manager 기술 사양: what the free and Pro editions each include.
• Virtual Machine Manager의 클러스터 관리: adding and removing hosts.
• Virtual Machine Manager의 보호: protection plans, replication and switchover.
• Synology VMM 백서: how VMM Pro licensing and cluster features fit together, the background to this VMM Pro license guide.

자주 묻는 질문 #