DAS enquiry

[Enquiries]

Dear Team,

Hope you can assist. I wish to purchase a DAS - as a media storage, and wish to connect my current HDDs to it. At present I am using a 2-bay HDD docking station, but have been looking at the following:
QNAP TR-004
Yottamaster 4 Bay Type C Hard Drive Enclosure
CENMATE 4 Bay Hard Drive Enclosure

The above will be connected to my existing Synology NAS via USB 3 connection - to act as extended storage also.
My only concern is that I don;t want to lose data - and with these can i simply put my existing data laden HDDinto them without an issue? Or will they start to initialise the disks thus deleteing whats already on them? I have read many a reviews and stories - and hence am a bit concerned - hence i thought I'd seek your advice on these.
The CENMATE and Yottamaster i can pickup for around the £100-£130 mark - so is acceptable - whereas the QNAP is around the £250 mark.

Thank you for you advice - and God Bless.
James

[ed]

Thanks for your message, and happy to help — this is a great question, and one that comes up often, especially when reusing drives already filled with data.

When it comes to DAS (Direct Attached Storage) enclosures, whether or not your data remains intact really depends on how the enclosure handles the drives — and unfortunately, not all enclosures behave the same way.

Here's a breakdown of your options:
1. QNAP TR-004
Caution needed here — the TR-004 uses QNAP’s own software to manage RAID, and when first connected, it will prompt to initialise or format the drives unless it recognises a QNAP-specific format.

If you insert existing drives full of data (formatted by Windows, macOS, or Synology), it’s very likely they’ll be unreadable without reinitialising.

It's best used with fresh drives, or when managed directly by a QNAP NAS that formats them through Storage & Snapshots Manager.

2. Yottamaster / CENMATE 4-Bay USB Enclosures
These are generally JBOD or hardware RAID enclosures with no proprietary software.

In most cases, if you’re using them in JBOD mode, and insert a drive that’s formatted in NTFS or exFAT (typical Windows formats), the enclosure will just pass the drive through as-is.

However — if you're using drives that were previously part of a RAID array (especially from a NAS), or formatted in ext4 or Btrfs (common on Synology), your NAS may not mount them automatically via USB.

Connecting to a Synology NAS via USB
Synology’s DSM treats USB-connected storage differently:

It expects drives to be formatted in FAT32, exFAT (if licensed), or NTFS.

It won’t mount ext4/Btrfs partitions from another NAS just by plugging them in via USB.

You can use an enclosure like Yottamaster to house new drives, format them via DSM, and use them as external backup or cold storage, but not seamlessly as “extended” storage for active shares or services.

So, can you just pop your drives in and go?
In short: not safely.
If your drives already have data and were used in a different environment (Windows, NAS, RAID), plugging them into a new DAS may:

Show them as unreadable

Prompt you to reformat

In some cases, not recognise them at all