Is RAID 5 really a solution?

I use Time Machine too. I also use SuperDuper to create backups of critical file such as original raw files, music, LR Catalogs and additional back ups of the photo folders on my working HD.

I end up four copies (on-site) of files I consider critical. I also occasionally do a back up to two other HDs I store off-site.

One of my New Year's Resolution is to make archival TiFFs from finished Series and Projects and store them in the Cloud.

Time Machine has saved me from silly errors several times. I have only experienced a couple of outright personal HD failures in the past 20 years. However in a previous life my laboratory depended on about 25 SUN Microsystems workstations. In those ancient days we used tape drives to do incremental and weekly back ups at night. The monthly tapes were sent to a salt mine for storage. We never used RAID systems. As I remember, we would loose a couple of HDs due to outright failure every year. Our lab was used by corporate R&D drug discovery scientists. We were proud HD failures never affected their ability to do their daily work.
 
A RAID certainly isn't a total solution. Backups are still necessary. For instance, a RAID will not protect you if a file gets corrupted or deleted by accident. Or if there's a flood, fire or tornado. An off-site backup is always advised! For desktop use though, it's the fastest and safest option to work from (going back to the RAID 1 mentioned earlier).

For that, a removeable drive is great, or better yet - two. Once a week or month, copy your files to the removeable drive - and swap it out with your remote one. Keep it at a friend's house, work, relative or safety deposit box.
 
Raid 5 is a good solution for disk failures, but if your controller card is broken you are in for a nasty surprise.
I have a simple and cheap solution based on 2 3 TB external USB drives.
Based on the archive bit I weekly backup all changed or new files to 1 external drive.
Furthermore, I can do a simple daily backup after a major project, and I do a backup before holidays.
Once a month, Or before we go on holidays, my son comes home with the 2nd drive and during dinertime I make a backup to the 2nd drive, which he takes home again.
The net result is that I am protected for a technology failure with the maximum loss of 1 weeks worth of data and against theft or a major disaster with the maximum loss of a month worth of data.
The cost is just the 2 external drives.
Additional bonus: all files are directly readable on a password protected disk, no striping which needs to be calculated or any other deciphering algorithm which is either clumsy or takes a lot of cpu power.
No automation besides a simple cmd file.
Works as a charm.
 
Dante_Stella said:
Am I crazy? My conclusion was to use a striped set for working files, a RAID NAS (not on all the time) to deal with backups, and a couple of clones in external housings (FW800/USB3/eSATA) for the real disasters.
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It makes perfect sense, You could use 4x4TB drives in a 4-drive TB enclosure like those made by Promise or OWC, in RAID 0+1, and back up to a pair of 6TB drives in rotation between home and office. Make sure you get drives made specifically for NAS, as ordinary consumer drives don't handle vibration from other drives nearby very well, and their default behavior when encountering problems (keep retrying indefinitely) cause the storage subsystem to hang rather than fail over.

My data set is only 2TB, so I make do with 2x1TB Samsung 850 Pro SSDs RAID 0 in a Promise J4 (expandable to 4 drives), backing up to a pair of WD My Passport Studio 2TB FW800 drives (with encryption and a solid aluminum case for heat dissipation).

One last thing to guard against is silent data corruption, which is an increasing risk as drive makers keep whittling quality down as HDD margins keep falling. The best safeguard is a filesystem like ZFS with integrity checking (and it also offers snapshots, the best safeguard against human error). Some NAS operating systems (FreeBSD and OpenSolaris/Illumos/Nexenta) support it, and there is a Mac implementation available, if a little rough on the edges:
https://openzfsonosx.org/
It's a tragedy Apple was scared off ZFS by NetApp's patent trolling.

Last but not least: do not rely on either Time Machine nor Drobo, as they have inexcusable failure modes with data loss even without a drive failure.

raid said:
My name was spelled this way by Germans as they read word phonetically ... Rah-ed
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Could be worse. My father's name is Sadiq, and "sadique" means "sadistic" in French, so when he moved to Frence in the 1970s, he'd always have people doing a double take when he introduced himself. Perhaps he would have been better served by Voltaire's corruption of the name, "Zadig".
 
I have a RAID 6 - 16tb set up for work, mainly to handle about 12tb of video footage/library.

RAID 5 and 6 make a lot more sense when you're dealing with video.
Being able to stripe across several drives means quicker access when you're editing video footage, then add in producers looking for footage while you're editing and you'll understand why high RAID numbers work so well.

Add the internal back up capacity of RAID 6 and it's nice to know your footage is that much safer.
 
I use a combination of Time Machine plus two hard drives on which I store my pictures. I am coming to prefer dedicated hard drives for photos, because I can store some seldom-viewed photos off the iMac, to conserve onboard storage space. My problem with using two separate outboard hard drives is that over time I have got some pictures on one drive and some on the other, and I think it would take me forever to get all pictures on both drives. But with RAID, that would be automatic. I think RAID 1 might be right for me.
 
All of these hardware-based external RAID solutions have single points of failure - power supplies, bridge board controllers, etc - in other words, the box itself is the weak link. Personally, I would never use a RAID solution outside of RAID 1 for storing important data - if I cant access the data with the failure of "any" component in the system, then all the disk redundancy in the world is pointless. The fact is that with many of the available/affordable RAID boxes, subsequent models from the same vendor are not backward compatible with earlier virtualised RAID 5/6 volumes. RAID 5/6 being more "cost effective" is poor economics if you can't read the data due to a controller failure.

I've personally had a box hardware failure on a QNAP RAID solution running 2x RAID 1 - 1 set as the primary and the second as a backup; after the failure all I needed to do was remove one drive and insert it into a bare-drive enclosure and with EXT-3 Linux drivers on the Mac, could read everything immediately.
 
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