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How to not lose data. Backup drive listed as dead.
I have a ReadyNas pro 4, chassy only, it's stocked with 3 WD Red Nas drives of 3TB each and I only have about 400GBs left of free space. I just saw in the Admin suite (the webapp for the NAS) that w...
WD30EFAXInorite wrote:
but wanted to ask how to go about replacing the backup disk (disk 1) and not lose any data?
To clarify: There is no individual "backup disk" in your setup. You are running XRAID (in particular RAID-5) which has single redundancy. But there is no dedicated parity disk - instead the data and parity blocks are spread evenly across the disks.
Your data should be ok right now, but it is certainly at risk. I do recommend making a backup of the NAS before you go further, as a second disk issue will result in data loss. Multiple disk failures with RAID are more common than you might think - the disks usually are installed at the same time, are identical models, in the same environment, and running under the same workload.
Backup over the network to a USB drive in a PC is generally faster than using USB (your NAS only supports USB 2).
Recovery isn't a difficult - you can just hot-swap disk 1 with the new (blank) disk. It will resync, and eventually tell you it is finished (and the volume will be marked as fully redundant). After that, you can hot-insert disk 4. I recommend doing this with the NAS running, as the software then detects the removal and reinsertion, and doesn't have to figure out what changed while it was shut down.
Inorite wrote:
I have a ReadyNas pro 4, chassy only, it's stocked with 3 WD Red Nas drives of 3TB each
Don't get the WD30EFAX as it is SMR. Instead go with the WD30EFZX. SMR doesn't work very well in RAID (and is particularly problematic if you are using OS 6). Generally avoid the drives current branded as "WD Reds", and get the ones branded as "Red Plus". You can also go with a Seagate Ironwolf (they are all CMR).
BTW, if you are running 4.2.x firmware, it is possible to convert your NAS to run OS-6. But it does require a factory reset, so you do need a full backup.
WD30EFAXInorite wrote:
but wanted to ask how to go about replacing the backup disk (disk 1) and not lose any data?
To clarify: There is no individual "backup disk" in your setup. You are running XRAID (in particular RAID-5) which has single redundancy. But there is no dedicated parity disk - instead the data and parity blocks are spread evenly across the disks.
Your data should be ok right now, but it is certainly at risk. I do recommend making a backup of the NAS before you go further, as a second disk issue will result in data loss. Multiple disk failures with RAID are more common than you might think - the disks usually are installed at the same time, are identical models, in the same environment, and running under the same workload.
Backup over the network to a USB drive in a PC is generally faster than using USB (your NAS only supports USB 2).
Recovery isn't a difficult - you can just hot-swap disk 1 with the new (blank) disk. It will resync, and eventually tell you it is finished (and the volume will be marked as fully redundant). After that, you can hot-insert disk 4. I recommend doing this with the NAS running, as the software then detects the removal and reinsertion, and doesn't have to figure out what changed while it was shut down.
Inorite wrote:
I have a ReadyNas pro 4, chassy only, it's stocked with 3 WD Red Nas drives of 3TB each
Don't get the WD30EFAX as it is SMR. Instead go with the WD30EFZX. SMR doesn't work very well in RAID (and is particularly problematic if you are using OS 6). Generally avoid the drives current branded as "WD Reds", and get the ones branded as "Red Plus". You can also go with a Seagate Ironwolf (they are all CMR).
BTW, if you are running 4.2.x firmware, it is possible to convert your NAS to run OS-6. But it does require a factory reset, so you do need a full backup.
Since you are still running RAIDiator4.2.x on your Pro4, then you will eventually run into expansion limits. Assuming you started with the 3x3TB drives. then the limit is that you cannot expand beyond 16TB. You can use the RAID calculator at https://rdconfigurator.netgear.com/raid/index.html to see what you will get from various drive combinations, but keep in mind that it does not account for expansion limitations since it is designed for OS6 systems.
You could just replace the bad 3TB with another of equal size, but that will limit the impact of adding a 4th drive. With 3x3TB, adding another drive 3TB or larger will only add 3TB. On the other hand, you could go with a larger replacement and an equally sized additional one and use all the space on them (up to 10TB so you don't exceed the expansion limit).
The other option is to update to OS6. It's not officially supported, but does work on your Pro4. The process is destructive to your data, but you really need to consider making a backup now (if you don't have one already), so this could be a good time to make the switch. If you want to go that way, we can provide more details on how to do it (it's not like a normal OS update).
So you're saying that the three 3TB drives currently in there, I can replace the dead one, allow everything to sync and that will get me back to having the security blanket of backup. And if I want and can make that new drive and add another both being...say 4 or 6TB each and I'll get the advantage of the backup and the additional drive space those 4 or 6TB drives provide even though the other non-dead drives are 3TB?
If yes, then that's what I'll do and as the 3TB drives die, I'll replace with larger capacity.
Cool! You guys are awesome!
Inorite wrote:
So you're saying that the three 3TB drives currently in there, I can replace the dead one, allow everything to sync and that will get me back to having the security blanket of backup. And if I want and can make that new drive and add another both being...say 4 or 6TB each and I'll get the advantage of the backup and the additional drive space those 4 or 6TB drives provide even though the other non-dead drives are 3TB?
RAID parity isn't the same as backup. But I would agree that you'd the benefit of single redundancy RAID.
You could certainly replace the dead drive with a larger size. You'd get no space benefit now, but if you would when you add a new disk to slot 4 (or replace another 3 TB drive).
If you started with 3x3TB, then you can expand up to about 14 TB. To reach that you'd replace the dead disk with an 8 TB model, and then add another 8 TB drive in slot 4. At current prices, the total cost would be about $400 USD.
But if you started with a 3 TB volume (did the initial install with only one disk in place), then you can expand up to about 11 TB.
Though I think you should consider converting the Pro to OS-6. That doesn't have any expansion limits, so you have more options on upgrading capacity.
Inorite wrote:
If yes, then that's what I'll do and as the 3TB drives die, I'll replace with larger capacity.That is the beauty of RAID, and XRAID in particular for better expandability than many other forms. Except that you will quickly run into the expansion limit of RAIDiator 4.2.x that are based on the small size of drives available at the time it was written. How quickly depends on where your volume size started, as in StephenB's examples.
Thinking of RAID as "backup" can make you think you have more protection than you really do. This forum is full of posts from folks who lost all their data because they thought that way. RAID can help in many situations, especially keeping the data available instead of the system being down to recover from independent backup. But there are events that can take out the whole volume, including redundancy, A second drive failure on your NAS while you make this decision is just such an event, and there is always hardware failure, fire, theft, etc. Only independent backup on a completely separate device is true backup. And even then, co-location of the main and backup devices leaves both vulnerable to theft, fire, etc. The level of importance of your data dictates the level and location of backup you need.
So, since you really should be looking into real backup (one or more USB drives with a format your PC can read directly, like NTFS, works well), then you can also use this opportunity to upgrade to OS6 and lose the expansion limits. OS6 conversion requires you offload the data and then re-load it afterward, which is why the backup becomes a part of the conversion plan, but then goes on to give you true backup as you keep it updated.
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