Quote:
Originally Posted by wpns
With the box in RAID-1 (mirror) mode, Infrant told me I could pull a drive, stick another drive in, and keep theone I pulled as a fully functional offsite backup.
It's never worked. Even the latest (4.1.4) firmware either doesn't flash the lights when the drive is removed, or hangs when putting another drive in, and Infrant/Netgear keep insisting it works, but never actually make it work.
If you get a chance, can you try this with the new one? Hopefully they rewrote the firmware from the ground up (which it's needed badly for years now), but I suspect it's a port...
I've certainly bought my last one (three on the shelf as I write this), but it'd be nice to know if they finally solved the problem...
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wpns - using RAID-1 hot-pull as a method of backup is insane. I've posted previously about this. There are a few reasons why you should never ever do this. First - RAID is designed to be a "first level" method of data protection. That means it is supposed to protect the live data on your system. You still need to do backups, but RAID is supposed to protect against most problems, so you only need to go to your backups in the case of a real catastrophe. RAID protects the live running data - there is no guarantee about disks that are pulled. By design, pulled disks are crap. RAID makes no effort to ensure that the data on those disks is meaningful in any way.
Second, when you pull a disk, there are multiple levels of commit that you have just broken. What guarantee do you have that the NAS wasn't right in the middle of saving a file right when you pulled the disk? Just because you made sure all your clients were not writing anything doesn't mean the NAS wasn't clearing a cache or something - you simply do not know. When you do not know, you should EXPECT corruption.
Third, your file system is not cleanly dismounted. Think about it. Say for instance you want to keep a safe copy of your Windows data somewhere, and you are planning to pull the disk that is in your Windows machine. Wouldn't you make sure you did a clean shutdown and the drive is dismounted properly before pulling out the disk? You wouldn't just pull the power plug and kill the machine, then pull the disk right? That's exactly what you are doing to the contents of the disk when you hot-pull a RAID1 drive.
Fourth, think of what RAID1 is all about - protection against drive failure. Now, think about how hard your drives are working during a typical day. Failure is most likely when the drive is most busy. If each day you hot-pull that disk, not only have you just walked away from redundancy until your new replacement disk is all mirrored again, you've also just put your drives to work - HEAVY work - remirroring. Guaranteed your disks are working waaaay harder during the re-mirror process than at any other time during the day. So just when they are most likely to fail (when they are working the hardest) you have also intentionally removed the RAID protection at this same time too - that's just plain CRAZY!
Fifth, when you hot-pull a drive, it is powering off right in the middle of running - it has not been safetied, and it is MOVING (i.e. sliding out of your NAS). No matter how carefully and how smoothly you pull that drive, compared to the fine tolerances of space between the heads and the platter, you are giving it a massively rocky ride. Are you sure you aren't causing the heads to crash onto the platter while you are doing this? Where have you ever read that it is safe for the disk to hot-pull a good drive? Hot-pull is meant for drives that are already dead. Plain and simple.
Bottom line - when RAID was designed, it was never intended as a method of hot-pull-backup. For the reasons outlined above, it should never be done. Think about it this way: Backups are important. They protect your precious data. Backup solutions (such as backup software or synchronizing tools like rsync) are designed specifically for doing exactly this job - backing up your important stuff. If your data is really so important, why would you rely on a method that was never intended to even work, to protect it, when there are other, much better methods that were actually designed to do this job properly? For examply, why would you try to put new tires on your car while driving down the road, when there are perfectly good garages you could pull into, and they can do it right?
I regularly see people on many different forums complaining about trying to use RAID1-hot-pull as a backup method and they always seem to have problems - makes me shake my head in disbelief every time. They mustn't really care about their data, or they would use a proper backup method.