I have ReadyNAS NV+ device which has been working just fine with 4 2 terabyte drive in XRAID configuration. I have read that sometimes spots on the drive go bad and unless scrubbing is done those sports may not be detected until a rebuild of the system is required and by that time it's too late. Since ReadyNAS NV+ does not have scrubbing, should I perform a "Volume Scan"?
If the volume scan fails, will I loose the entire array? In other words, is Volume Scan destructive?
Also, what is the difference between volume scan and resync? Should I be doing regular Resync instead?
Resync affects the RAID striping. Basically, the separate disks are aggregated together into a single volume by the RAID striping. That single volume is formatted, and information stored in it. Volume Scans look at the formatted data - particularly the file directories, and checks them for consistency. Resync is looking at / rebuilding the RAID striping underneath.
File scrubbing is like a volume scan, except that it includes checking all the files; not just the directories.
Doing a volume scan periodically is a good idea. The volume scan itself is non-destructive, though of course if there is an error that needs correcting, there could possibly be some negative consequences. However, I think that if you tried to access the files affected by those errors you would basically see the same problems. In any event, you should maintain backups, and not count on RAID to protect your data.
Thanks Stephen. Is there anything I can do on my ReadyNas NV+ to come close to scrubbing?
You mentioned that if the scan finds issues there may be negative consequences? Will I loose my entire volume, or is it just going to expose files which are bad? Is it recommended that I do a scan if I have not done it for a long time?
If you can read (or re-write) all the files on the volume periodically, that has a similar benefit to scrubbing.
For instance, if you are using FrontView backup, you can adjust the settings to create new "from scratch" backup every 4 weeks (instead of the normal incremental backup). If the NV+ is the backup target, you can make the same adjustment (rewriting every share from scratch every 4 weeks).
As far as losing the volume goes - any automatic repair carries some risk. If really shouldn't do any damage, but there is some small possibility that it will. It's hard to say much more than that. Also, I think there are some cases where your NV+ will automatically run a volume scan. So at some point, it will run.
However, I don't know if Netgear has any recommendation on volume scans or not. I run them, as I'd rather see issues surface sooner rather than later.
I also maintain backups, so even if damage were done I could still recover the data. If your concern about loss is because you don't have a backup, then my strong recommendation is to put a backup plan of some sort in place.
Lack of a backup is a concern to me. I currently have about 5.5T total storage via 4x2gb disks in XRAID configuration. Could I connect a HUB to the ReadyNAS attach 3 2tb external drives and somehow backup to those? I am not sure if that would work. What backup strategy do you use?
My main backup is to my old ReadyNAS (some folders from my Pro to old Duo, the rest to my old NV+) I also have several internal hard drives in my two desktops, and backup NAS folders to those drives as well.
However, backing up to USB drives is certainly a good way.
You can connect a hub directly to the ReadyNAS and attach the USB drives to it. Backup is then done with Frontview. That works well if you are ok with formatting your USB drives as ext (linux format). However, the NV+ v1 writes extremely slowly to NTFS formatted drives.
If the NAS is your only Linux device (I suspect it is), then you will want the option of reading your backup drives from your PC. Since the NAS is so slow at NTFS, it is quicker to connect the USB drives to your PC, and run the backup over your network. If you don't have a gigabit router you will want to get a gigabit switch (which will speed your network up, but still let you use your existing router).
You can use FrontView to back up to the PC, though I find it easier to use a windows tool called Robocopy. Robocopy is a command line tool, but it is easy to create a script to do the backup. Once you have the script, you can just click on it to run it.
