Originally Posted by bryansj
Just goes to show that RAID isn't backup.
... and that very few actually backup their RAID arrays.
I think the theme of the day is: practicality
So, users should stay realistic and choose the approach that best fits their reality rather than stress themselves with strict ideals.
If I am in a situation where my array is too large for practical backup, I will go with a scheme where I don't lose all my data if I lose more disks than the tolerance level.
Originally Posted by itznfb
This whole discussion started because I made this statement:
spectrum vehemently disagrees with this due to a want to represent his software as something where your data is "safer" which just doesn't hold water. For me, personally software RAID is fine for my Blu-ray collection but there is no way in hell my photography collection is leaving my RAID1 array. Technically still a "media" array. My photos sit on 2 hardware RAID1 volumes with 4 - 3TB disks each. So I have 6TB available for photo storage with 8 disks. It's costly yes but it's something that software RAID can't match unless I use the same capacity loss and the same $ investment.
Also, I know that I will never be at the mercy of parity calculation which isn't reliable. Not when I'm talking about my photos anyway. I still prefer hardware RAID5 for my movies (even though I'm using FlexRAID currently for testing) just because I like hardware RAID.
Bottom line is for critical data people are still going to choose RAID1 because as I've said over and over a block copy is a safer redundancy method than any algorithm used in parity calculation. And yes I still backup my photos off site.
Again... RAID1 IS the most simple solution. Say you only need 3TB for your media collection. There is no reason not to use RAID1 as there is no thought to it whatsoever.
I too run RAID1 for my most critical data as posted in this thread.
Why? Well, my most critical data fits snugly on a single 2TB drive. So, for RAID protection, mirroring just makes sense; and then, I backup the hell out of it.
In your case, however, you have 8 disks with 2 being used for data and 6 for redundancy.
My whole point has been that, if given 6 disks to protect 2 disks, I would go with a parity scheme supporting 6 parity drives rather than two separate RAID 1 arrays.
1. With a 6-parity configuration, I can lose any 6 disks and suffer zero data loss.
2. With 2x 4-way mirrors, losing 4 disks from the same set will cause the whole set to be lost. Losing 6 disks will certainly result in some data loss unlike with the parity configuration.
Listen, you have great protection as is with your setup, albeit over kill.
I wouldn't worry about much past the technicalities of this discussion.
I think people are fearful of parity based RAID because of the risk of losing a drive past the tolerance level during the restoration process and thereby losing everything.
It has happened, and solutions like FlexRAID address that problem to some level.