[Webinar] Learn how to a build a cloud-first strategyRegister Now

x
  • Status: Solved
  • Priority: Medium
  • Security: Public
  • Views: 359
  • Last Modified:

Which RAID is best for this issue?

I have a photography client that I am setting up a backup system for. Here is the scenario for drives:

1. Current Work
2. Completed Work
3. Archive

I am wondering what would be the best RAID setup? I need it to be fast, but have good redundancy. There will be a total of 6 drives used, Consisting of 18TB of storage.

Thanks!
0
bradbritton
Asked:
bradbritton
  • 4
  • 2
  • 2
  • +3
1 Solution
 
PapertripCommented:
RAID 5 is your best bet, provided your RAID controller supports it.  That will leave you with 15TB usable and the ability to lose 1 disk in the array without losing all data.  It is your responsibility to replace the failed disk asap, because if a 2nd disk fails then your data is lost.
0
 
PapertripCommented:
I should add that, depending on the capabilities of your controller, that you may be able to setup a hot spare as well for faster recovery if a disk fails.  That of course will consume another disk from the array, so your usable space will be decreased accordingly.
0
 
DavidCommented:
RAID6 is better in terms of data integrity and prevention of data loss   If you go RAID5, and just have on bad block on any of the surviving disks then you WILL lose data.  With this many disks, you have a very high probability that it will happen.  (100% probability from statistical perspective if you make mistake of using consumer/desktop disks instead of enterprise class drives. That is because the desktop drives don't have enough ECC bits to even account for the amount of data that will be read to perform a rebuild).

SO .;

1. enterprise class drives
2. RAID6.    

As far as I am concerned, if you don't do both, then it is unsatisfactory.
0
What is SQL Server and how does it work?

The purpose of this paper is to provide you background on SQL Server. It’s your self-study guide for learning fundamentals. It includes both the history of SQL and its technical basics. Concepts and definitions will form the solid foundation of your future DBA expertise.

 
PapertripCommented:
Adding to both our answers, remember that RAID of any level is not a sufficient backup.  Aside from which level you choose, if you don't also setup some sort of backup, you are asking for trouble.
0
 
DavidCommented:
.. and backup is not the same as archiving.  A lot of good your backups do if they are right next to the computer, and you have a fire or flood.
0
 
andyalderSaggar makers bottom knockerCommented:
Adding a bit more on the limitations of yoyr hardware, 6 drives, 18TB = 3TB disks, you'll need a RAID controller that can handle disks greater than 2.2TB / 2 TiB and you'll probably also need the controller to support creating a small boot logical disk or  have a pair of small disks to boot from as it's unlikely you can boot from anything bigger than 2TiB.

For archive you're probably better off getting a decent tape drive and making more than one archive copy / backup in case one goes bad, that could cut down required disk space by quite a lot, tapes store better ' longer than disks too and hold a lot of data cheaply although the drives are quite expensive.
0
 
BAmillerCommented:
I will confirm with dlethe that RAID  6 is by and far the superior choice in this scenerio - especially over RAID-5. Our company has been burned twice before with RAID-5 arrays that crashed and during the restore process, there were serveral bit errors that rendered the restore totally useless!  In each case, we spent over $10,000 to send our drives out to On-Track for recovery. That will never be allowed to happen again.  

RAID 6 will allow for the failure of 2 drives, thus creating that much more redundancy.  You will see a slight "hit" on the write speeds, but reads are decent and the double-redundacy is second to none imho.

However, get a good dedicated RAID Controller (LSI, Adaptec, etc.) and use Enterprise-class rated hard drives.
0
 
PapertripCommented:
I can't disagree with their suggestions for RAID 6.  I should have left out the "best bet" part of my original answer.  Both are valid options, both have pros/cons, and both depend on the needs of the client.  In hindsight I realize that RAID 6 is probably better for this scenario.

The enterprise level disk part however I definitely left out.  I'd just consider my answer an assisted solution at this point ;)

... but don't forget backups!
0
 
SelfGovernCommented:
Yes, DON'T forget backup!

Those disks will fail eventually, whether you use RAID 10 or RAID 6, and there's a certain window
you have where you're at risk of losing all the data due to a second (or third) drive failure.  In addition, RAID does nothing to protect you from a controller error, or user error (RAID does nothing to protect against accidental or malicious deletions) or theft, or fire, or flood, or....

For that much data, one of the most cost-effective solutions is still physical tape.  LTO-5 drives will be expensive, but the cartridges hold 1.5TB native (and you'll see close to native capacity with jpeg images, but probably good compression with tiff or other raw image files).

LTO-4 is 800GB per cartridge native, and LTO-3 only 400GB (multiply by your expected compression ratio).  LTO-4 is probably the sweet spot today in trading off cost and capacity, but LTO-5 is better if the budget allows for it -- far fewer cartridges means a much simpler backup process.

Yes, you can use some of the online services -- and perhaps should in addition to physical tape -- but consider how long the upload process will take, the cost of the monthly fees over years and decades, what happens if your service goes out of business, and -- important! -- how long it will take to restore that 5- or 10TB of data to your system if you lose your local RAID..  

While today's cheap big hard drives can store a lot of data cheaply, don't count on them for archival storage.   They are not designed for storage of data, particularly long-term -- when powered down.
0
 
aleghartCommented:
Archiving copies online would cost a fortune, unless you are happy with JPEG. Then, get a SmugMug account and test the limits of their "unlimited" storage for pictures.  Bandwidth might be an issue, as well as procedurally uploading the files.

DVD and Blu-ray media can last up to 50 years if well protected.  Consider a media vault that can keep environmental conditions OK for the discs.  And, remember to keep the door closed and latched at all times.  They are expensive and very heavy.  But, for a photographer, the concept of a big safe for archiving shouldn't be new.  10TB might break down to 250-300 Blu-ray discs.  If that's 10 years worth of photos, then you're looking at a much smaller safe than would be required for negs & trans.  The yearly or monthly purges would not be as significant.
0
 
BAmillerCommented:
As for backups - I could agree more more with all of the above posts . . . you've got to have a good solid backup strategy in place once you've opted for "whatever" RAID-array to use.

Being that we've been "burned" twice before already with RAID-5 restores, we eventually opted for RAID-6 on the File Servers, but you lose 2 drives to parity.  However, the added redundancy is money well spent (hard-drives are relatively cheap these days -- even Enterprise-class drives) - However, any RAID-Array is NOT a backup and should never be viewed as such -- it is simply providing redundancy.

Thus, your RAID-array is really only as good as your last backup.  Most companies have poor / lax "disaster recovery plans" in place (or none at all!) -- and if they do, many rarely test them to ensure that the system works!  

For us, we have RAID-6 on all File Servers for Redundancy
We have daily backups to disk using Backup Exec 2010 (those backup disk are in RAID-6 too)
We have nightly off-site backups of all file server data to off-site FTP Severs using BatchSync FTP 3.0.13 that only transfers "newly added data" for that day -- everything else is skipped, but we've got an off-site duplicate "mirror" of our data at two locations.
The off-site FTP Servers are in RAID-6 for redundancy and that data is backed-up daily with Backup Exec 2010 (and those backup drives are in RAID-6)
Thus, you could say that we have backups-of-backups-of-backups-of-backups.

I sleep well at night now . . .

Extreme?  Maybe.  However, face a situation where you have to fork over ~ $20K to get your data back and you learn really quickly . . . . : = )




0

Featured Post

Vote for the Most Valuable Expert

It’s time to recognize experts that go above and beyond with helpful solutions and engagement on site. Choose from the top experts in the Hall of Fame or on the right rail of your favorite topic page. Look for the blue “Nominate” button on their profile to vote.

  • 4
  • 2
  • 2
  • +3
Tackle projects and never again get stuck behind a technical roadblock.
Join Now