RN314 No volume exists after disc swap

This is why I have a second NAS and backup using RSYNC.    A NAS is not a backup.  If you don't have at least a second copy someplace, you don't have a backup.    When you have Terabytes of Data, the only practical way to backup is with another NAS.   2 days a week, my second NAS powers up to get ready for any new Data from my Main NAS to start copying over.  It does this late at night. In the morning it powers back down.  It's all automatic. 

Any number of things can happen to your NAS.  You ran into one of those.  Raid 5 ONLY gives you protection if 1 HDD fails.    When you pop a new HDD back in the other HDD(s) now have to work much harder than normal to rebuild the Data onto the new HDD.  This can be the time where another HDD can fail.   It's why I don't want to install all my HDD into a NAS at once.  In fact, I don't want to buy all my HDD from the same place all at once.   You don't want to end up with all your HDD from a bad batch.  But wear and tear is another thing,  So start out with 2 HDD for RAID1, when that is close to full, add a 3rd HDD.  It'll change to raid 5.  Then as that starts getting close to full, add that 4th.  When you put all 4 drives or however many drives in all at once at the same time.  They all equally have the same wear and tear on them.  My feelings on this matter is that it is a greater risk of more than 1 HDD failing on you at once.

I'm now working on expanding my NAS by going from 3TB drives to 8TB drives.   So I have 2 8TB drives in now and 4 3TB drives in my NAS.  I have another new 8TB drive just sitting here for when the time comes of getting short on space.    I have 2.8TB free right now.  So I won't put it in yet.  Those other 2 will have months of use and hours on them before installing this new drive.  The longer I can leave it out the better.  Anything to space the HDD use out. 

In fact a couple of days ago I got a message on my NAS about a possible failure of my HDD failing, even though it shows green and still good. The drive "Current Pending Sector Count is at 105" which is high?!?!  The other 5 drives show 0.   So I may be swapping that out sooner than later.  Right now I've been backing up to my other NAS which takes days.  I have about 15TB to copy over and this cheap ARM NAS is not FAST over the Network.  My Intel ReadyNAS 516 will pretty much MAX out my Gigabit Network.  This QNAP Arm NAS is only taking in Data at about 10Mb/s.   That is SSSLLLLOOOWWWW.

But again, things can go wrong.  In your case you had a second HDD take a dump in the process of Rebuilding your NAS.  That, in general, is the most likely time to have another HDD fail.   All the same brand, gotten at the same time, installed all at once, and all having the same hours on them.  It's almost asking for it.  RAID6 gives you 2HDD fail protection, but it's kind of silly to use on a small NAS.   You don't want to really use RAID 6 until you're into 7 or 8 drive or larger NAS.

You can also have the NAS just whatever.  Break down.  Catch fire.  You never know.  Maybe you get robbed.   Maybe your house burns down.  I have my 2 NAS in different places in my house.  Off-site would be better and I may do that at some point.    Once everything is copied onto it, copying anything new is not a big deal off-site.  In your case, a second HDD fail, a real backup protects you in that also.  A NAS is not a backup unless it's backing up another NAS.  Again 2 or more copies of a file is a backup.   I know it doesn't help you now.  

I  see that 3 of your HDD are over 5 years old.  All installed at the same time.  Your second HDD is showing just over 2 years old.  This is the drive you just installed and is suppose to be new?  It shows 17955 Hours on it. 17955 divided by 24 hours in a day equals 748.125 divided by 365 days a year equals 2.049, or just over 2 years.  I'm not seeing anything that is standing out BAD with any of the 4 HDD.   That's strange.  Maybe the system can be fixed. Hopefully, one of the Netgear Experts can help get you running again without losing any data?!?!  That would be best case.  Good luck, and for others reading this, BACKUP YOUR DATA if you care about not losing it.

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dave_directs wrote:

Thanks for the reply. Disk Info attached.

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Yes, disk 4 has two "pending sectors" - which are sectors that couldn't be read.  That could account for the failed resync.

You might want to shut down the NAS and test that drive in a Windows PC with Western Digital's lifeguard utility.