Think twice before committing to X-RAID or RAID-5. What is your recovery plan?

[illmatic]

TL;DR: Because I chose RAID-1 over X-RAID, I easily survived a disk failure. I'm back to having a working RAID-1 array, with no loss of data, no support contract, no data recovery fees, no proprietary programs, no shipping drives across the country, and my only cost (besides the replacement drive, of course) was a single SATA-to-USB device ($30). What worked? Boot up with Active@ LiveCD (http://www.livecd.com/) and use the File Manager.

5 years ago, when I bought my ReadyNAS, I engaged in these forums a debate between RAID-1 and X-RAID. My #1 priority was ability to recover data after a failure, while other people focused on maximizing disk space. Well, finally, one of my disks failed recently. No warning ahead of time, no SMART data indicating a disk might fail, just "Disk failure detected" in the logs after it was too late. My shares or volumes were inaccessible via normal Windows networking, and not available in RAIDiator either. There was no indication whether my data was still intact or not. Because I was using RAID-1, I believed that the good disk should still be OK, the hard part was figuring out how to read it.

I connected the working drive to my laptop using a SATA-to-USB converter. Many software ideas did not work because the RAID data volume is seen as RAW and not Ext4, so Ext4 readers in Windows don't work. In the end it was one of the simplest options: I booted up using the Active@ LiveCD with the drive already attached. Once booted, the simple Linux File Manager ("Dolphin") was able to see and read all my files perfectly. I did NOT need any of the proprietary software on the CD, just the simple File Manager. And of course, it was possible to plug in a portable drive and copy everything from the source drive to the portable backup. Easy and Free. (I will also note that the basic file manager on the UFS Explorer emergency CD worked as well, although I found Dolphin slightly easier to use)

(Later, I also found out that the volumes and shares were all available directly from the NAS after removing the failed drive. In other words, when the good drive was by itself without a failed mirror drive, the NAS made all the data and files available again, with an "unprotected" warning. So essentially, you don't even need a LiveCD... but the biggest advantage is being able to copy data at USB3 speed)

Finally, restoring the NAS to RAID-1 was incredibly easy. I put the good drive back into its original slot on the ReadyNAS, ordered a replacement drive (same make and model as the failed drive), and popped it in. The ReadyNAS immediately began copying everything, it had a percentage indicator on the front panel, and only took about 10 hours to mirror 2.7 GB of data.

Contrast this with the restoration of an X-RAID array. Start with trying to connect 3 drives to a laptop, plus a portable backup drive. You can easily run out of ports (especially at USB3 speed) or power outlets to plug everything in. Sure you can overcvome this but you're paying for SATA-to-USB enclosures, USB hubs, power strips, etc. Now, is there a definitive guide to restoring an XRAID array to read its data? Not from Netgear. There are some helpful tips and recommendations in these forums but certainly nothing that is foolproof or easy. There is a good chance you'll need to learn to use mdadm. And if it isn't working, is it because the array is not set up correctly, or the data itself is corrupted. Assuming you aren't a full time data recovery expert, how would you tell? There are many more reports of destroyed, overwritten and lost data, or expensive support contracts, than there are of successful DIY recoveries. And if it isn't DIY, it's certainly going to be expensive and often require you to send the physical drives somewhere.

Bottom line: after going through this process, I am more convinced than ever that RAID-1 is superior to any other RAID option, unless your data is disposable or 100% backed up in real-time. RAID-1 is not failsafe of course (fire, theft, deleting/overwriting a file, etc), but it is just as compatible with any other backup methods (2nd NAS, drive-swapping, portable backup drives, rsync, cloud storage) as any other RAID type, PLUS you get the benefit of the easiest and fastest recovery process in the case of a drive failure.

I would also like to thank StephenB for participating in the initial debate. His ability to see the pros and cons of both methods was appreciated.

[StephenB]

The best news is that you avoided data loss 

I agree it is important to think through your backup/recovery plan when you plan your installation.  I think your assessment of RAID-1 is accurate - easiest to recover, at the cost of 50% overhead for redundancy.

I use XRAID myself, and I maintain good backups on several devices (and also one backup in the cloud - Crashplan).

[TeknoJnky]

For a lot of people who choose x-raid (raid5 or 6), simply have more data than will fit on a single disk.

You make good obvervation regarding the ease of recovery of raid 1, but of course you are also paying double for the available the disk space.

it all comes down to risk and cost and convenience.

while raid 1 is potentially easier to recover, raid 1 (nor raid 5 or 6) will still not protect you from theft, from virus or malacious users deleting or corrupting your data, it won't protect from mother nature (fire/flood/etc), and it won't protect you if both drives fail before you can get your data recovered.

So as always, it is critical that you have multiple backups of your important data. That means multiple copies, spread out on multiple devices, and ideally in multiple locations.

[cpu8088]

think twice?

already done that

my bulk of data consists of 90% static movies and tv series

used to have redundancy raid 5 but now all on 2 disk raid 0 and jbod with pro 6. however i use a rackmount 2120 v2 2x2 disks raid 0 for backup. plus dynamic data such as image backup of pcs i additionally use scheduled backup to external usb hard drive.

my reasoning is that with raid 5 or 6 the resync time is too long and it hinders performance. there are instances another hard drive would fail during resync. much easier to destroy the array/volume, insert new drive and recreate arry then execute backup