# RAID system



## atross (Apr 5, 2022)

Hello everyone,

I'm new to the forum and would like to ask a question for comments and suggestions.  I currently use a RAID 1 storage system from Glyph as well as a cloud backup from Backblaze.  I recently purchased the Lightroom CC/6 book and after reading some of the material, realized from the Lightroom Queen that a RAID 1 system is not the best way to go.  I knew when I purchased the RAID 1 system that it wasn't the best but it was better than what I had at the time.  Now I'm considering a RAID 5 or 6 system that is hot-swappable; however, there are so many different systems out there I really don't know which is best.  I have been reading reviews of the different manufacturers but I need some help/suggestions.  I would really appreciate any suggestions from your guys and gals.


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## atross (Apr 5, 2022)

Okay, after reading further in the Lightroom CC/6 book, I read where the Queen uses Chronosync; however, it mentioned at the Chronosync website that Backblaze is an offline storage source that it uses.  Since I already subscribe to Backblaze, is it possible to have both without any issues and is it advisable to do so?


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## clee01l (Apr 5, 2022)

RAID is not Backup.  It only serves a purpose in environments where 24X7 access to the data is required.   You do not need that.  Banks and other big businesses need to have their data available 24X7 to clients. Convert your RAID system to use individual disks as EHDs or Build one large volume using JBOD (Just a Bunch Of Disks).  

Off site backup is nice to make sure that your local disk are preserved so that you can recover WHEN your local disk fails. However getting recovered over the intents is slow and tedious.  If Backblaze offers to sent you a recovery disk This is usually quite expensive as opposed to having  a backup disk local.
Chronosync is an OK solution for Local backup, but your Mac comes free with TimeMachine.  Why no use that with BackBlaze and have two separate backups,  One Locally and One in the Cloud?

I run both TimeMachine and Acronis locally to backup all of my critical data.   TimeMachine backs up to two different local disks So I have available to recover a few files or a whole disk locally from three destination disks.  I chose not to use Backblaze  and I'm comfortable with the risk of losing data to fire, flood or pestilence.


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## Conrad Chavez (Apr 5, 2022)

The first question to answer is why RAID is being considered in the first place. There are three main problems that different RAID types historically solved: Uptime/redundancy (which like Cletus said, is not equivalent to  backup), speed, and capacity.

If you want *redundancy* to help guarantee uptime, that's what RAID 1 and 5 (safer) gets you. If one drive fails, another can be an immediate substitute because it maintains another copy of the data. But it isn’t a backup because anything that happens to the main drive is immediately copied to the second drive, so unlike a backup, the second drive can’t be used to recover from errors, file deletions, malware, or other mistakes. Because the second drive immediately copied the problem as soon as it happened.
If you want more *speed* than you get out of any single storage device you have, then you do RAID 0. But today, it’s simpler to buy an SSD, which will be much faster than any RAID of hard drives.
If you want more *capacity* than you can get with any single storage device you have, then you do RAID spanning. (Combine two 2TB drives to get one 4TB volume.) But today, it's simpler to buy a large enough single hard drive, because you can get an 18TB hard drive (they might have even bigger ones now).
Because none of those is a true backup, all still need to be backed up. Chronosync is a great tool for backing up to other local storage, but you can use any good backup software that does the same thing, or a cloud backup like Backblaze.

Because there are now better solutions for speed and capacity than RAID, the one remaining reason to set up a RAID is ensuring continuous unbroken uptime. But if you keep an up-to-date backup drive that you can simply slot in to replace a failed drive in 5 minutes and then get going again, any downtime will be minimal. Continuous uptime is more for businesses where the data being unavailable for 5 minutes could cost them thousands of dollars.

Maybe that will help you decide if you need a RAID to begin with, and it starts from the assumption that maybe you don’t.


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## Linwood Ferguson (Apr 7, 2022)

I'm sorry, two postings here seem to prefer raid 5 over raid 1.

Raid 5 is "better" only in that it is more efficient space-wise.  It is somewhat slower for reads, and MUCH slower for writes than Raid 1.

Raid 1 (for small number of disks) is by far the fastest redundant raid configuration.  (Raid 1+0, 1+0, or 10 is faster for larger number, but it is just a variation of Raid 1).

Note that Raid-0 is faster still but is not redundant.

Other than the cost of space, there is no reason in theory NOT to use Raid.  It is not a backup, but Raid-1 generally is a small benefit in performance and reliability (but at a 50% penalty of space).

I said in "Theory" - in Practice Raid for home use can introduce problems with that benefit because (a) the SOHO systems are generally not very well architected and the software may not work well, and (b) SOHO users are often not competent to deal with raid when it fails, and recovery and replacement of a drive may not be straightforward because, see (a).

I tend to agree that for most users you are better off with a layered backup than RAID and one backup (and never every rely on Raid alone).  But I wanted to jump in because I think the idea that Raid is actually bad, or that Raid 5 is better than Raid 1, needed clarification.


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