I’m new to RAID HDs and had a couple of questions. I plan on buying an external RAID 1 HD for photo file redundancy.
Some questions I’m hoping the experienced RAID folks can answer:
1) What happens if a file on one of the drives gets corrupted? Do I get an error message? Does the RAID configuration automatically recover the faulty file?
2) Is there the likely chance that a corrupted file on one drive will overwrite/copy the good file?
3) I see USB 2, USB 3 and Ethernet interface. All I want to do is store photo files, do you think USB2/3 would be adequate? I currently use external HDs w/USB 2 (and USB 2 looks to suit my needs).
4) Is there generally a “good” brand that won’t break the bank?
1. the system should be keeping the 2 drives in sync. most likely, 1 of the drives will fail and a light (or something) will come on indicating that and you need to get the drive replaced. 1 file doesn't just magically get corrupted.
2. no, see #1. the usual way of corruption happening is the user f*g things up and th RAID will happily delete the file. The RAID takes care of everything and the computer only sees it as a single normal drive. All the housekeeping is done invisibly by the RAID controller.
RAID 1 is normally used for high system availability. It is not a substitute for a backup, as any corrupted or malware infected files, etc. will be the same on both drives.
as any corrupted or malware infected files, etc. will be the same on both drives.
Yikes. I've had corrupted files in the past due to an HD sector fault (I'm not so worried about a virus/malware infection). So a RAID 1 system wouldn't help here? I was hoping it would.
Unreadable sector != corrupted file. You are correct that if one RAID 1 drive cannot be read after a certain number of retries, the data will be read from the other drive. For bulk data storage I prefer RAID 6 (or RAID 5 if only a few drives). RAID 1 is for boot drives IMO, although with SSDs offerung such high performance nowadays I just use a single boot SSD and image that separately.
In my experience the safest is still to get two external harddisk and load your photos on both. The advantage is that you can keep the disks in a different physical place as well in the end.
Feb 11, 2012 at 09:28 PM
Lars Johnsson Offline • • • • • • • Upload & Sell: Off
ViscaB wrote:
In my experience the safest is still to get two external harddisk and load your photos on both. The advantage is that you can keep the disks in a different physical place as well in the end.
It will be exactly the same with two raid (even better and safer) and keeping one in a different location.
The problem with two different external harddrives is that when it get full, then you need four drives. And so on..........
As was said above, RAID 1 should never be used for backup. It adds complexity but does not give you a second FULL copy. Other Raid variants, including things like DROBO, can give logical drives larger than you can get from a single physical drive. If you need more than 3TB of storage on a single drive, they are useful for that purpose as Lars mentioned. Just remember that, no matter what the design is, they count as a single copy only.
I wouldn't suggest running raid. They just have a lot of problems. I'd say use a DROBO or MirrorFolder. I personally use MirrorFolder and it's basically file syncing. It's awesome in my opinion and works with internal and external drives.
Alot of conflicting info here and if IT was not my primary occupation I would get confused.
RAID: Rudundant Array of independent disks. This means if one disk fails or has corrupted sectors you do not lose data. However, it does not mean you have two copies of your file.
The most usefull setup is to have your computer setup with RAID1. This reduces the likelyhood of system failure. For backup, RAID does not provide as much advantage. This is because your backup drive will not have as many hours (running time with the disks spinning) and is less likely to fail. It is better to backup 2 copies, 1 local and 1 remote.
No matter how many drives or copies, if they are at 1 location they can be destroyed by 1 event.
Good Luck,
Anthony
The real fun with RAID occurs when the disk controller goes beserk and writes crap over all the drives
RAID is not a backup solution, it is an uptime and performance solution. The nature of RAID does mean that there is an improvement in information security relative to a single drive, but its nowhere near as safe as having the data on two drives in two physically separate enclosures.
No expert but here's what I thought and did.
First, I had two ext LaCie HD's for backup and alternated backing up to them. But I wasnt disciplined. A big problem. One died after several years but relatively little use since I backed up every couple of months. I know, that's not what you should do.
So, knowing I wasnt going to be disciplined, knowing I wasnt going to have two locations, I bought a WD My Book 6 TB HD comprised of two internal HD's and configured it as RAID 1. With this product its either RAID 0 or RAID 1. As I understand it, now the external backup HD is creating two identical backup copies, protecting me against the failure of either one of the enclose backup HD's.
Many things can, of course, still go wrong. These are not bootable to my understanding. The RAID controller can mess up. I can copy a virus to the backup drives. The housing, ext or internal connections can get damaged. But at least I am not subject to the failure of one HD. The WD warranty was longer than most of the LaCie's and getting better reliability ratings recently.
I did price searches, ended up thru BHphoto.
They come formatted for Mac and had to be reformatted. I had trouble reformatting thru one of my laptops for inexplicable reasons, was able to format it thru a different laptop. Now all is well, backing up my primary laptop continously and the extra laptop intermittently.
A Raid1 setup should be easier for you to maintain. A faulty drive is just replaced by another drive.
Both raid1 or off-site backup are a step to safety with a backup/fail-over solution.
.
Raid is part of a backup/redundancy solution.
Corruption of a drive should not affect operability. And data of the lost drive can be rebuild.
Just combining Raid with an off-site backup is creating a redundant solution.
What to do:
1 Buy a good empty shell and fill it with (at this moment)
- WD caviar BLACK
Good drives for Raid. Buy the most 'cost-efficient' drives. I think the 1TB or 2 TB drives are best priced atm.
2 Buy another empty shell for off-site backup. Once every week/month make a full backup and store it somewhere else.
RAID is not backup. RAID is for performance and/or high availability uptime.
Consider a file in a RAID unit to be a single copy of the file, regardless of how many stripes or mirrors or disks there are. If you delete a file accidentally, it is gone, regardless of how many stripes or mirrors or disks there are.
Remember and implement this: three copies of every file with one of them off-site.
(even better and safer) and keeping one in a different location.