Upgrading drive on ReadyNAS Pro 4

Many folks (not just ReadyNAS users) have had problems using Seagate 3 TB "DM" drives in RAID arrays.

The HCL for legacy NAS hasn't been updated in long time, so it is no longer a useful guide for purchase.  Ironwolf Pro drives should work fine (as would WDC Red Pro or WDC Gold).  Many users also find that WDC Red or Ironwolf work quite will - I use the WDC Reds myself.

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dave1234 wrote:

Is there a way to replace all 4 drives without doing it all at once and losing all my data?  Can I replace one at a time & let the NAS rebuild the data on that one before replacing the next one?  I didn't think you were supposed to mix different drives.  If I replace a 3TB drive with a 4TB, will the system format it as a 3TB to match the others?

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XRAID volumes are expandable (within limits noted below).  You can replace (hot-swap) one drive, then wait for it to fully resync.  The volume size won't change at this step.  Then you can hot-swap the second drive.  After resync, the system will prompt you to reboot.  It will then expand the volume by 1 TB.   

After that, you can hot-swap the remaining two drives (one at a time), and the volume will expand 1 TB with each disk - leaving you with a 12 TB (10.9 TiB) volume.

This assumes you won't hit the expansion limits

• a volume cannot be expanded over 16 TiB total size
• a volume cannot be expanded more than 8 TiB over its starting size

The first limit can't be hit in your case, but if you started with 2x3TB when you recreated the volume some years ago you might hit the second limit when you replace the last drive.  If you do hit the limit, the only workaround is to do a factory reset (which is destructive, and requires a backup).

What firmware are you running?  Current firmware is 4.2.31, if you are running older firmware I recommend updating it before you begin.