akfishguide Loc: PA

I about to purchase a new computer system. The system will start with a new iMac and new external storage systems. I have never owned a RAID system and have no experience with one. The question I have is: Which is better, a RAID 1 system or two independent external HD's? I know the RAID 1 system has hot swappable HD's and thought that way I could swap the system out every couple of weeks or so, but was told that if I do that, the off site storage disk, when put back into the RAID system, would be reformatted and all the info would be lost. Also I was told that the disk that is removed, can only be read by the RAID system it came from, so if that system goes down in its entirety, any external storage is totally useless anyhow. So if that is true, is it better to have a RAID system, or two independent external HD's? Thank you in advance for your guidance.

jerryc41 Loc: Catskill Mts of NY

I use two external drives, right next to my computer for backing up. I also have a NAS with RAID 1 because each drive has the same data. If one fails, I still have a good copy. This system is handy for accessing data on different computers. Unlike some other people, I don't keep it running all the time - only when I back up and want to use it for another computer.

Do you plan to keep all your images on the new iMac? Most people keep them on an external drive to save space on the computer's drive. I would recommend a large HSGT drive. Then put it in a case with a fan.

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http://smile.amazon.com/gp/product/B013WODZH0?psc=1&redirect=true&ref_=oh_aui_detailpage_o02_s00

Hard drive reliability -

https://www.backblaze.com/blog/best-hard-drive/
http://improvephotography.com/31924/best-hard-drive-for-photographers/
http://lifehacker.com/how-long-will-my-hard-drives-really-last-1700405627
http://www.zdnet.com/article/solid-state-disks-lose-data-if-left-without-power-for-just-a-few-days/
http://the10bestreview.com/top-10-best-external-hard-drives-in-2015-reviews/

Capture48 Loc: Arizona

Which RAID is correct for you is really hard to say. Depends on your tolerance for data loss.

RAID 1= Is Mirroring. Data from one disk is copied to the other in the background. This is the simplest and cheapest fault tolerance you can get. This tolerance level can be achieved by software or hardware. It is slower than RAID 5, and may cause a drag on your system depending on how it is implemented. In case of a failure with RAID 1 you simply break the mirror and you are up on running on the good disk. There may be systems with Hot swappable RAID 1 disks now, frankly I've not used 1 for years.

Raid 5 = Striping with parity. This means your data and parity data is copied across a number of disks, usually a minimum of 3. With this type of fault tolerance you get 2 times your smallest disk in the set for storage. So if you have 3 disks the first 1TB, the second 3TB, and the third 3TB, you get 2TB of storage. This is because all disks have to formatted alike and since you can't format a 1TB to accommodate 3TB of data, all disks are formatted to the smallest disk. Why only 2X the disk, one disk is always used for parity data, so if any one disk fails the system can recover. Consumer level NAS devices like this often have HOT SWAPPING, meaning at any time you can pull out that 1TB disk and put in a 3TB disk and get up to 6TB of storage. The disadvantage of any RAID/NAS system is it leads people into a false believe that they have a great backup solution. Make no mistake a RAID/NAS is NOT a backup solution, it's a storage solution.

There are different RAID levels but these two are by far the most common, and most others are variations on these two.

Dngallagher Loc: Wilmington De.

A RAID systems provides you with redundancy for your data. With a RAID system your data is written to at least 2 drives simultaneously, A RAID system appears one drive to the computer, with two single drives that is not the case, they are two single drives...any redundancy must be done manually.

If one drive of a raid system fails, the computer can still function because at least 1 drive of the raid set is still running and your data is there. Once the failed drive is replaced the raid array will rebuilt the data onto the new drive and you are again running the raid set with data on multiple drives in case another drive in the raid set were to fail.

With two single drives, if one fails your data on it is gone most likely, and your only hope of recovery is with a backup.

All that being said, RAID is your best option when adding any drives if possible...the simple fact of having the redundancy in drives when one fails usually means that the system keeps running with no loss of data.

Dngallagher Loc: Wilmington De.

All true and correct - RAID is REDUNDANCY, FAULT TOLERANCE, not backup....no matter how many drives your RAID array consists of, maintain a separate, tested and quality backup.

:thumbup:

akfishguide Loc: PA

Thank you for your info. I now know a lot more than I did. As I understand it now, the RAID system will back up the computer but an additional backup should be used for storing Data (Photos). I hope this is right.

Dngallagher Loc: Wilmington De.

NO, not quite.. the RAID system is NOT a backup.... you store your data on the raid for redundancy of drives.... so your data is in more than one place... YOU need a BACKUP system in case you lose everything in a disaster.... and preferably, think about a third system - OFF SITE backups in case you lose your entire system.

Capture48 Loc: Arizona

WRONG, RAID is storage, not backup. IT can be used to make a copy of your data or drives, but that is a copy not a backup.

Capture48 Loc: Arizona

:thumbup: :thumbup:

Dngallagher Loc: Wilmington De.

Capture48 Loc: Arizona

This is a good article, the only thing it does not explain is why a RAID/NAS does not make a good backup. It does say that it is not a backup, but here is why it's not such a good backup stratagy.

RAID is normally on the same network as your data. This means it's just as vulnerable to a virus, or accidental deletion. It can be burned and lost in a fire, or stole in a robbery / theft. I had a washing machine hose break and flood my basement years ago and ruin some electronics.

Whereas a good backup includes an offsite copy of your data. This means your entire dwelling can be wisked away in a hurricane. You can move dwellings and still recover your data through an offsite backup.

Dngallagher Loc: Wilmington De.

Good points indeed...

I use raid on connected external drives for my images, and do two local backups to single connected drive and one that gets disconnected and kept in a fireproof box, also a non raid drive, and an off site backup with Crashplan.

At this point, if I lose something and it is not recoverable shame on me ;)

Capture48 Loc: Arizona

I use CrashPlan on my MAC to backup my external LaCie drive. I also have a 9TB NAS that is mounted as a folder on my Wife's PC. That folder looks like any other Windows folder and gets backed up with Carbonite

Dngallagher Loc: Wilmington De.

:thumbup:

akfishguide Loc: PA

OK lots of info to enlighten me. Thank You very much. So my thoughts of what a RAID system was for was completely wrong. It is backup but not storage. So let me know if this is a wrong thought process. Perhaps two external 4 TB HD's and a 3rd 4TB external HD that can be rotated with say #1 external HD and stored in a firesafe. Also offsite storage. Now all I use for photography at this time is Lightroom and Final Cut ProX. I have Lightroom and Photoshop downloaded from the 'cloud' and currently store all my photos on 2 4TB external HD's attached to my laptop (which is why I want a desktop iMac). Based on my current thought process, if I add one more 4TB External, I could rotate them for external storage. Also you recommend offsite storage and you listed one I had never heard of, and I also saw Carbonite which I have heard of. All I am looking to make sure I do not lose is photos and video's I have created. I am not a gamer and only use computers for photography and email and for information, like what I have gained from you. Based on your expertise, am I looking at this right or is there something I am missing?