Posts: 3
Registered: ‎2011-08-30

Replacement disk?

We have a ReadyNAs NV + (4425) firmware 4.00c1p2 [1.00a042].
It has 4 disks (ST3500320NS) with RAID Level 5.

Disk 2 is reported dead and needs to be replaced. Unfortunately we are not able to purchase an identical disk since it's not manufactured any longer. Is it possible to hot swap the dead disk with a replacement disk of same size, cache and speed in Raid 5? For example this disk, ST3500410SV, the only thing that differs is the response time i think.

I have read the manual and if we would have been using X-Raid instead of Raid 5 this wouldn't have been an issue I suppose, we could replace the disk with another one with different specs? But for Raid 5 I don't know if we are able to do this.

We are thinking of upgrading the storing capacity of the Readynas by replacing current disks with larger ones. Would this be a good way in doing so?
- Make a backup from the Readynas via the USB port to an external drive.
- Reset the Readynas to factory settings, upgrade the firmware.
- Replace all disks with > 1 TB disks with X-Raid setup.
- Restore the backup from the external USB drive.

Kind regards
NETGEAR Moderator
Posts: 43,325
Registered: ‎2011-06-07

Re: Replacement disk?

You can replace the disk with a disk of equal or larger capacity. It should be from the hardware compatibility list ( Since you are using RAID-5 your volume is not expandable, but you can add an additional volume if there is unallocated space.

4.00c1p2 is approaching 4 (edit: oops, 4 not 5) years of age:

That's incredibly old firmware. That firmware certainly doesn't support disks with greater than 1TB of capacity, I'm not sure about 1TB disks.

I would suggest you do the following:
1. Backup all data
2. Verify backup is good
3. If you wish purchase a replacement 500GB (or greater disk) and put this in the NAS. This will replace the dead disk and give you a redundant volume.
4. Upgrade to the latest RAIDiator (currently 4.1.7:, note that 4.1.8 is in public beta at the moment and a production release should happen soon).
5. Do a System > Config Backup (keep zip file that is downloaded as this is what you need to restore)
6. Power down and remove disks (label order). If you did step 3 you'll be able to put the disks back in the NAS later (preferably same order as before) if something goes wrong with the later steps.
7. Insert 4 new disks from the compatibility list.
8. Do a factory default via the boot menu: (
9. Restore Config Backup
10. Restore data from backup

If you choose to backup to a USB drive connected to the ReadyNAS you should format the drive to use EXT3 (under Volumes > USB Storage in Frontview). You should also enable fast USB writes (

To verify your backup, I would recommend you edit your backup job's properties to use Rsync and run the backup job again. Take a look at Rsync backup to USB disk

Welcome to the forum!
Posts: 3
Registered: ‎2011-08-30

Re: Replacement disk?

Thank you for a detailed and quick response!
Yes we do need to upgrade the firmware, but first I would like to secure the data in a backup.

But it is perfectly safe to replace the dead disk with another, not identical disk, via hot swap in Raid 5?
NETGEAR Moderator
Posts: 43,325
Registered: ‎2011-06-07

Re: Replacement disk?

Yes. If it is smaller in capacity than the old one it'll be rejected. Otherwise so long as it's a compatible one it should be fine.

The speed of course will be limited by the speed of the slowest disk.
Posts: 3
Registered: ‎2011-08-30

Re: Replacement disk?

Great, thanks a lot.
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