[GH-ISSUE #498] Migrating DS916+ (unverified 3rd party drives) to DS425+ #170

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opened 2026-03-07 19:16:34 +03:00 by kerem · 3 comments

kerem commented

2026-03-07 19:16:34 +03:00

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Originally created by @ks2018ks on GitHub (Jul 31, 2025).
Original GitHub issue: https://github.com/007revad/Synology_HDD_db/issues/498

The guide indicates "Migrate unverified 3rd party drives from other Synology" works with 'Lots of warnings' removable with Synology HDD db script, but I'm not clear whether I need to first install DSM on the 425+ - i..e. if migration means transferring storage pools or includes initial set-up?

...in which case do I need to do this first?: https://www.reddit.com/r/synology/comments/1kaab7v/script_installing_dsm_on_ds925_using_unsupported/

The 916+ has 3x 14TB Toshiba MG07ACA14TE as a single volume storage pool, setup as SHR with 1 disk fault tolerance (and a 500GB Samsung 850 EVO SSD as a cache.)

Dave's test results with a 925+](https://www.reddit.com/r/synology/comments/1kf7obz/my_ds925_test_results indicate 'you cannot use 3rd party SATA SSDs as a cache. Not even for a migrated HDD volume.', which probably doesn't matter given the 425+ has M.2 NVMe slots for that. It also indicates 'you cannot use a 3rd party HDD as a hot spare.' I'm not sure whether that means only 2 of the 3 migrated Toshiba drives will be recognised upon migration or if it means it will show lots of warnings.

If I've understood correctly, the Synology_HDD_db script will clear the warnings, but I'm wondering whether for expansion I should add a 4th Toshiba MG09SCA14TE to the 916+ volume first (removing the Samsung SSD, and expanding the SHR) and then migrate all 4 to the 425+, or whether it would be better to migrate the 3 disks then say buy a Synology 12 or 16TB drive and add it to the 425+?

Advice appreciated:

Install DSM first or migrate directly?
Will the migrate recognise the existing spare (3rd Toshiba drive) as a hot spare after the Synology HDD db script?
Better to buy a 4th Toshiba drive for expanding the 916+ and then migrate or a 'verified/compatible' similar sized drive after migration?

Thanks in advance

Originally created by @ks2018ks on GitHub (Jul 31, 2025). Original GitHub issue: https://github.com/007revad/Synology_HDD_db/issues/498 The guide indicates "Migrate unverified 3rd party drives from other Synology" works with 'Lots of warnings' removable with Synology HDD db script, but I'm not clear whether I need to first install DSM on the 425+ - i..e. if migration means transferring storage pools or includes initial set-up? ...in which case do I need to do this first?: https://www.reddit.com/r/synology/comments/1kaab7v/script_installing_dsm_on_ds925_using_unsupported/ The 916+ has 3x 14TB Toshiba MG07ACA14TE as a single volume storage pool, setup as SHR with 1 disk fault tolerance (and a 500GB Samsung 850 EVO SSD as a cache.) Dave's test results with a 925+](https://www.reddit.com/r/synology/comments/1kf7obz/my_ds925_test_results indicate 'you cannot use 3rd party SATA SSDs as a cache. Not even for a migrated HDD volume.', which probably doesn't matter given the 425+ has M.2 NVMe slots for that. It also indicates 'you cannot use a 3rd party HDD as a hot spare.' I'm not sure whether that means only 2 of the 3 migrated Toshiba drives will be recognised upon migration or if it means it will show lots of warnings. If I've understood correctly, the Synology_HDD_db script will clear the warnings, but I'm wondering whether for expansion I should add a 4th Toshiba MG09SCA14TE to the 916+ volume first (removing the Samsung SSD, and expanding the SHR) and then migrate all 4 to the 425+, or whether it would be better to migrate the 3 disks then say buy a Synology 12 or 16TB drive and add it to the 425+? Advice appreciated: 1. Install DSM first or migrate directly? 2. Will the migrate recognise the existing spare (3rd Toshiba drive) as a hot spare after the Synology HDD db script? 3. Better to buy a 4th Toshiba drive for expanding the 916+ and then migrate or a 'verified/compatible' similar sized drive after migration? Thanks in advance

kerem commented

2026-03-07 19:16:35 +03:00

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@007revad commented on GitHub (Aug 1, 2025):

I would do this:

Disable the read-only cache on the DS916+.
Move your 3 HDDs and SSD to the DS425+.
Boot the DS425+.
Open Synology Assistant (or finds.synology.com) and let it migrate the HDDs.
Then download and run syno_hdd_db (and scheduled it to run at boot as root).
Next set the SSD as a read-only cache for the HDD volume.

Note: Your 3rd HDD is not a hot spare. Your volume (and data) are spread across all 3 drives. With SHR, and RAID 5, parity checksums for each file are spread across all 3 HDDs so that if any 1 drive fails the other 2 have the parity checksums to recreate the missing data from the failed 3rd HDD on a new 3rd HDD.

@007revad commented on GitHub (Aug 1, 2025): I would do this: 1. Disable the read-only cache on the DS916+. 2. Move your 3 HDDs and SSD to the DS425+. 3. Boot the DS425+. 4. Open Synology Assistant (or finds.synology.com) and let it migrate the HDDs. 5. Then download and run syno_hdd_db (and scheduled it to run at boot as root). 6. Next set the SSD as a read-only cache for the HDD volume. Note: Your 3rd HDD is not a hot spare. Your volume (and data) are spread across all 3 drives. With SHR, and RAID 5, parity checksums for each file are spread across all 3 HDDs so that if any 1 drive fails the other 2 have the parity checksums to recreate the missing data from the failed 3rd HDD on a new 3rd HDD.

kerem commented

2026-03-07 19:16:35 +03:00

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@ks2018ks commented on GitHub (Aug 1, 2025):

Many thanks for your reply here and hot spare clarification
(for some reason the Reddit sub kept deleting my post)

At step 4 Synology Assistant found the DSD425+ using a direct ethernet cable connection, declares it migratable and lets me assign an IP address in 192.168.1.x

but as soon as I clicked OK, it went back to saying the connection failed

EDIT

I was afraid to reboot it in case it was updating in the background, but accidentally dislodged the power cable as I tried the other LAN port, and found that after reboot the IP was assigned. Although not reachable via the LAN, the laptop with the direct ethernet link found it and I was able to start migration via the web browser Synology assistant (after over an hour trying to download the .pat file from Synology (which seemed to keep losing it's connection)

After the 10 minutes countdown it lost its IP address again and took going through the process above twice before being able to log in to it (using the pre-migration account credentials)

@ks2018ks commented on GitHub (Aug 1, 2025): Many thanks for your reply here and hot spare clarification (for some reason the Reddit sub kept deleting my post) At step 4 Synology Assistant found the DSD425+ using a direct ethernet cable connection, declares it migratable and lets me assign an IP address in 192.168.1.x <img width="1678" height="364" alt="Image" src="https://github.com/user-attachments/assets/336c7875-0119-488e-884b-41076bae8b9f" /> but as soon as I clicked OK, it went back to saying the connection failed <img width="1729" height="59" alt="Image" src="https://github.com/user-attachments/assets/301c785f-3ace-4528-b99a-49035288c1b6" /> EDIT I was afraid to reboot it in case it was updating in the background, but accidentally dislodged the power cable as I tried the other LAN port, and found that after reboot the IP was assigned. Although not reachable via the LAN, the laptop with the direct ethernet link found it and I was able to start migration via the web browser Synology assistant (after over an hour trying to download the .pat file from Synology (which seemed to keep losing it's connection) After the 10 minutes countdown it lost its IP address again and took going through the process above twice before being able to log in to it (using the pre-migration account credentials)

kerem commented

2026-03-07 19:16:35 +03:00

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@007revad commented on GitHub (Aug 2, 2025):

Migration only takes 2 or 3 minutes.

When you say "direct ethernet connection" I assume you mean an ethernet cable directly between the NAS and your computer? Just get a cheap ethernet switch and connect your router, NAS and computer to it.

@007revad commented on GitHub (Aug 2, 2025): Migration only takes 2 or 3 minutes. When you say "direct ethernet connection" I assume you mean an ethernet cable directly between the NAS and your computer? Just get a cheap ethernet switch and connect your router, NAS and computer to it.