It doesn't use any form of RAID - it uses disk pooling. I have drives of all sizes in it, from 1TB to 4TB, and every file is protected by being on at least 2 physical disks. With no special formatting. I can take any disk out of it and attach it to any computer that can recognize NTFS format and read my data.
Congratulations, you're doing nothing which can't be done by anything else. There's good reasons nobody does that, though..
And 4 disks often leads to RAID 5 which is just bad.
No worse than your 'at least two copies' with a variety of fun exceptions.
No, the pool does not increase read throughput but it also does not decrease write throughput as the copy process happens int he background. That's probably the ONLY exposure on the whole thing - if i copy a new file to the server and the drive the file landed on dies RIGHT THEN, it likely did not have time to replicate to another drive and is lost.
RAID does not decrease write throughput notably - actually, a decent non-mirror array writes faster than a single member drive. So you're losing out on both + more fragility. And no, it's far from the only exposure - see below.
You're doing nothing in particular other systems can't do (okay, yours is a bit more integrated with Windows, unsurprisingly). I'm glad it works for you, but it's not better.
How does 'your' duplication scheme cope with read errors? Windows typically just panics uselessly. How about corrupted reads? Just go with whatever we read first and assume that single medium is perfect? Will it end up propagating corruption across the duplicates or do you just end up with a pile of inconsistent blocks? Does it ever check for consistency?
It's certainly no worse than a consumer grade NAS. And it works with Macs, too, if I had any.
This is home use. It's not form commercial grade applications. Our business customers with large storage requirements have true SANs with lots of spindles and all sorts of proper redundancy. As for reliability and recovery, I had ONE disk fail over the 9 years I have been running this, and it didn't crash the server. Windows isn't going to blue screen on a failure of a data only drive. the system disk - very likely. I COULD have made that redundant with hardware level mirroring but I didn't - it's just not that critical, because I can replace that drive and reinstall the OS and remount the old drive pool. Or read any disk like I said, no special driver needed. At the time, this was novel, you couldn't just "do it with everything". Current versions of Windows Server have it built in, but that's at the block level and you CAN'T just stick a disk from the pool in another machine and read it. Most NAS devices support JBOD and various RAID levels, not all do drive pooling. Performance - seems to be a complete non-issue as I easily saturate wired Gb ethernet connections copying files to and from the server, and it can stream multiple HD streams simultaneously - with 5400 RPM low power drives, only the OS system disk is a 7200 RPM drive.
Guess I am just lucky, plenty of drives, 9 years, only one ever failed. No data loss. Yes, similar to a RAID 5 in that if 2 drives fail at once I will lose data - but not ALL data, just those files that happened to have other copies on the two failed drives. That's significantly better than a RAID 5 when 2 disks fail. And since with one failure it doesn't have to rebuild the entire pool, just make an extra copy of the files that happened to be on the failed drive, recovery time is greatly reduced from a RAID 5 rebuild time, again reducing exposure time. I can read/write it from my Linux box, it just doesn't have access to the backup features, those are limited to Windows and OSX.
No, it's not perfect, but it has been a solid, stable, and very reliable option. Especially since it's ALSO backed up outside of my house - and I have done test restores so I am confident my choice of backup providers is reliable. The only thing actually on the server that is not replaceable (with varying degrees of effort) are my photos. Should I lose all my MP3's i COULD pull all my CDs out and rip them all again. Though naturally I would like to avoid that.
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