Best way to swap drives ReadyNAS nv+ v2

t1000-forever wrote:

1. Create a backup of the existing data on one of the Hitachi DK7SAD300 drives (done).
2. Remove existing two Western Digital WD30EFRX drives from my ReadyNAS. Install three of the four Hitachi DK7SAD300 drives in my ReadyNAS; perform a factory reset and install using RaidAR version 4.3.8; my plan is to use X-raid2 again, so will end up with a single volume.
3. Copy the data back from the backup created under (1).
4. Finally, insert the final Hitachi DK7SAD300 drive in the ReadyNAS (destroying the backup on there).

That will work, and one advantage is that you can reinsert the WD drives (NAS powered down) if something goes wrong. (With your procedure I suggest powering down the NAS before replacing all the drives). 

Though if the drives are healthy, you could also

1. hot insert one of the Hitachi drives to slot 3 and wait for the resync to complete
2. hot insert a second Hitachi drive to slot 4 and wait for the resync to complete

At that point you will also that a 9 TB volume.  You could then save the remaining Hitachi drives until you have a failure.  

If you don't think the WD drives are reliable, then a variation is to 

1. hot-swap one of the Hitachi drives with one of the WD drives, and wait for resync to complete.  
2. hot-swap again.  Note both WD drives also serve as backups, since RAID-1 mirrors both drives.
3. hot insert the third drive into slot 3
4. hot insert the fourth drive into slot 4.

Although both WD drives serve as backups, they might not be synced with each other (since something might get written to the NAS during step 1).  But you can boot with either disk installed (other slots empty), and still have full access to your data.

t1000-forever wrote:

I got hold of four 3 TB Hitachi DK7SAD300 drives;

These are old models.  I am wondering if you are paying too much attention to the compatibility list?  It hasn't been updated in a very long time and is best ignored.

Seagate Ironwolf, WD Red Plus, and Toshiba N300 are all NAS-purposed drives that will work well in your NAS.  Pro models (or enterprise-class drives) will also work well.  Avoid desktop class, as they are almost all using SMR technology that isn't well suited to RAID.  

If you go forward with the Hitachi drives, then make sure to test them in a PC before using them.  I suggest a full non-destructive test, followed by a full write test.  Hitachi's disk business was acquired by Western Digital in 2012, so you can try WD's KitFox utility in a Windows PC:

• https://support-en.wd.com/app/answers/detailweb/a_id/51537

t1000-forever wrote:

And should I use or 4.3.8 of RaidAR software? I also came across 6.5.0.

Either will work with X-RAID.  If you were to go with FlexRAID you'd need to use 4.3.8.

After manually testing the three 3 TB Hitachi DK7SAD300 drives, I installed them in my ReadyNAS nv+ v2. Upon boot, it detected that a new install was required (it indicated an install of firmware followed by a 10 minute wait). Using RaidAR version 4.3.8, it detected the NAS on the network. I chose to set it up using X-RAID-2 with a single volume. Later that day, it performed a sync of the volume to (I think) the third drive successfully.

Next up I started copying data back from my backup using Robocopy over SMB/ethernet. Performance was reasonable at about 250 Mbps, however it stopped copying data after about 25 GB. At that point, the SMB share was no longer accessible somehow and I was no longer able to ping the NAS from anywhere in my network. I was able to gracefully shutdown the NAS using the Power button, after a reboot I was able to resume copying data.

Unfortunately, the same pattern keeps repeating itself. After copying some data, the NAS ceases to be accessible over the network again. See screenshot below to illustrate what's happening.

Any suggestions? Are there some logs I should look at? Could it be that the 3 TB Hitachi DK7SAD300 drives are not working well in this NAS? I never encountered this issue using the 3 TB Western Digital WD30EFRX drives.

Thanks.

That's a CMR drive, so should work well.  It sounds like you may be overwhelming the OS.  Try using a backup job on the NAS instead of robocopy.  It may go slower, but not needed to keep re-starting would be preferable, I think.