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[rockzilla]

Hi,

I have 2 x 2TB harddisk in raid1 at the moment. If I add another 2 x 2TB harddisk and chose to reconfigure to Raid5, will I lose the data that is in the original raid1?

I afraid to add them now, losing 1.8TB of data is going to be a nightmare. 

Thanks in advance

[JavaLawyer]

The DNS-345 manual contains the following excerpt:

You can install one hard drive in Standard mode during the initial setup and upgrade to RAID 1 or RAID 5 with RAID migration in the future. The migration process can be carried out without data loss.

You can do the following with RAID migration:

• Migrate the system from Non-RAID mode to RAID 1 or RAID 5
• Migrate the system from RAID 1 to RAID 5

The text clearly indicates that you can migrate from Standard to RAID-1/RAID-5 without data loss, but the text is not 100% clear regarding migration from RAID-1 to RAID-5.

Keep in mind that RAID-1 and RAID-5 provide redundancy but are NOT considered a backup. If your data is important, I strongly suggest you maintain a separate physical backup of your data somewhere other than your RAID array. DNS-345 - Data Backup vs. Redundancy

I am not sure whether your proposed migration will retain your data. You can always install a third HDD as a standard volume and copy your data over from the RAID-1, and then convert the new standard volume to RAID-5.

I will ask D-Link to provide some clarification on this issue  

[rockzilla]

Update:

I bite the bullet and added 2 more 2TB hard disk and click reconfigure from raid 1 to raid 5. The good new is everything is still there after more than 50 hours of migration. The bad new is I only get 3.57TB of disk space, instead of 5.58TB. Anyone have such experience of raid 5 missing hard disk space

Thanks in advance.

[JavaLawyer]

It looks like one of the HDDs wasn't picked up. Are you sure only one volume is available? Does the web interface indicate that the RAID-5 array includes all four HDDs?

[rockzilla]

It is hard to tell cause what i see is only

Under/Hard Drive Configuration/Current Raid Type
Volume_1 : Raid 5

Under/S.M.A.R.T Test
Can see all 4 hard drive

Under/Scan Disk
ONly 2 Option : All Volume(s) & Volume_1

Under/System Status/Hard Disk Information/
Disk1 WDC WD20EARX-00PASB0 WD-WMAZA******* 44°C / 111°F 2000 GB Normal
Disk2 WDC WD20EARX-00PASB0 WD-WMAZA******* 45°C / 113°F 2000 GB Normal
Disk3 WDC WD20EARS-00J2GB0 WD-WCAYY******* 46°C / 114°F 2000 GB Normal
Disk4 WDC WD20EARS-00J2GB0 WD-WCAYY******* 46°C / 114°F 2000 GB Normal

  The raid 1 to raid 4 reconfiguration did reflect disk 3 & 4 complete with 100%.

[rockzilla]

Update:

I tried removing hard disk one by one to test the integrity of the raid, and below is the finding.

When remove Disk 1: Whole raid is unusable
When remove Disk 2: Whole raid is unusable
When remove Disk 3: Whole raid is unusable
When remove Disk 4: degraded

After restarting NAS and re-sync back raid, result still the same, still missing one disk drive space.