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new to RAID, setup advice

D

dcslacker

macrumors member
Original poster
Apr 23, 2004
44
1
I just got an OWC Mercury Elite RAID unit that can store two hard drives in RAID or independent modes. The purpose is to store my old video projects for long term storage and other media backup. The drives are WD Caviar Greens with the same model ID: WD20EARS (not the newest model, but from a couple years ago). This is my first time to use RAID storage of any sort.

The plan is to put both of them in the Elite and then put my old projects and media on them. Originally, I planned to use RAID1, which is the mirror setup and can rebuild if one drive fails. However, from what I read, it is highly recommended to use the same model HDD, which I am, but I worry about what happens when a drive fails and I need to replace it and the WD20EARS are no longer made.

How important is it to have identical model HDDs? If one fails, is it okay to replace it with, say the newer model of the Caviar Green?

If having a different HDD model will screw up the RAID, then would it be better to set up the Elite in "independent" mode, which shows both drives as separate volumes? Then I would manually duplicate the data on both drives and if one fails, I can put in a newer and/or larger capacity HDD and manually duplicate the data over from the existing HDD.

What would be best?
 
nuckinfutz said:
Same model is ideal but not necessary.

Same size is probably more important.
Click to expand...

Agreed.

I'd also add that RAID 1 gives you redundancy but not a backup. If a file corrupts, a lighting strike fries your gear or you accidentally delete something RAID 1 will not protect you.


Lethal
 
Good to know that same model isn't necessary.

Lethal, so are you saying that if I have my two drives in RAID 1 and if a file corrupts, then both drives are screwed up? I thought the purpose of RAID was to have redundancy was to be able to salvage data. So, does RAID 1 only salvage data if there is a physical failure (drive dies) but if a file corrupts somewhere, then the the RAID will fail?

Just want to make sure I'm understanding this aspect of RAID. I think I may just go with two independent drives with files manually duplicated between them. I don't think I really need a RAID setup just for backing up old projects.
 
Two drives are only mirrored. You need at least three for a proper RAID array.

RAID is not Backup, consider offsite storage or the Amazon S3 cloud.

A Synology type RAID supports different drive sizes.
 
dcslacker said:
So, does RAID 1 only salvage data if there is a physical failure (drive dies) but if a file corrupts somewhere, then the the RAID will fail?
Click to expand...
The RAID itself won't fail, but both copies of your data will be corrupt so the attempt at using RAID 1 as a backup solution would have failed. RAID1 provides redundancy in case of a HDD failure and that is all.

Just want to make sure I'm understanding this aspect of RAID. I think I may just go with two independent drives with files manually duplicated between them. I don't think I really need a RAID setup just for backing up old projects.
Click to expand...
Even if you use two separate disks make sure the files match exactly as just doing a drag and drop via Find won't always make an exact copy. If you use command+i to compare the original file and the copied file you can compare the sizes down to the byte and they should match exactly. This is one instance where using a RAID 1 is better than using two independent drives. You'll also want to make sure the drives are only powered up and connected when you need them.

For example, the HDDs I back up my machines with are only plugged in and powered on when I do my weekly backups. All other times they are kept unplugged. Ideally they would be kept in a different geographical location in case of flood, fire or burglary but I haven't figured out feasible way to do that yet.

Important docs and small files I also backup in the Cloud, but all the cloud storage providers say they aren't responsible if your data disappears so don't put all your eggs in one basket. That's the general rule for backing up anyway. If it's not saved in two different places it's not saved at all.


Lethal
 
dcslacker said:
Good to know that same model isn't necessary.

Lethal, so are you saying that if I have my two drives in RAID 1 and if a file corrupts, then both drives are screwed up? I thought the purpose of RAID was to have redundancy was to be able to salvage data. So, does RAID 1 only salvage data if there is a physical failure (drive dies) but if a file corrupts somewhere, then the the RAID will fail?

Just want to make sure I'm understanding this aspect of RAID. I think I may just go with two independent drives with files manually duplicated between them. I don't think I really need a RAID setup just for backing up old projects.
Click to expand...

RAID is not backup. Period.

If you accidentally delete a file from your RAID (or it gets corrupted, or whatever), it's gone from both drives.
 
Wow, this is new information to me. I definitely do not need RAID. And I didn't know that a drag and drop copy isn't always an exact copy. While more time consuming, the manual copy with command-I checking will work best for me.

This setup is just for archiving older personal/school video projects, nothing critical for a workplace environment. The drives will only be plugged in to transfer data; afterwards it'll be in stored environment.

While it would be ideal to have multiple copies in multiple places, it's simply not practical for me at the moment.

Thanks for the input, everyone. :apple:
 
Sorry to revive an old thread, but I am having the same problem as the OP. After one too many drives recieivng bad sectors only after a year or two, my trust in HDD's has dwindled. RAID1 seems like a great solution for archiving my old projects, but obviously not an ideal backup.

Because of this, I am thinking of having Crash plan backup my RAID1, which is off-site and also keeps revisions. What do you guys think?
 
MacOG728893 said:
Sorry to revive an old thread, but I am having the same problem as the OP. After one too many drives recieivng bad sectors only after a year or two, my trust in HDD's has dwindled. RAID1 seems like a great solution for archiving my old projects, but obviously not an ideal backup.

Because of this, I am thinking of having Crash plan backup my RAID1, which is off-site and also keeps revisions. What do you guys think?
Click to expand...

As you found out RAID is a poor archive. You'd be better off using the drive independently

The very best solution and the one even CrashPlan's web site recommends is to have a local backup to disk and a remote backup to Crashplan.

If this is off-line archive I'd un-RAID the disks and use the drive independently.

So the ideal plan is (1) Time Machine kept on-line full time, (2) disk backup kept off-line in a fire safe some place and (3) Cloud backup like Crashplan or Backblaze.

Crashplan's software is good because it has a million options. Backblaze is nice because it is easy enough your grandmother could set it up and it's faster as they don't throttle bandwidth like crash plan does.
 
ChrisA said:
As you found out RAID is a poor archive. You'd be better off using the drive independently

The very best solution and the one even CrashPlan's web site recommends is to have a local backup to disk and a remote backup to Crashplan.

If this is off-line archive I'd un-RAID the disks and use the drive independently.

So the ideal plan is (1) Time Machine kept on-line full time, (2) disk backup kept off-line in a fire safe some place and (3) Cloud backup like Crashplan or Backblaze.

Crashplan's software is good because it has a million options. Backblaze is nice because it is easy enough your grandmother could set it up and it's faster as they don't throttle bandwidth like crash plan does.
Click to expand...

I'm not fully understanding what you're saying, but I know what you're getting at. I made this quick diagram to more accurately describe my backup plan. Does this help?

p0ai.jpg
 
MacOG728893 said:
Sorry to revive an old thread, but I am having the same problem as the OP. After one too many drives recieivng bad sectors only after a year or two, my trust in HDD's has dwindled. RAID1 seems like a great solution for archiving my old projects, but obviously not an ideal backup.

Because of this, I am thinking of having Crash plan backup my RAID1, which is off-site and also keeps revisions. What do you guys think?
Click to expand...

The easy part -

1) use something like Crash plan or similar. Just be aware to get started may take some doing if you have a lot of data and most home internet upload is relatively slow. They, as someone else mentioned in a similar mode of discussion for an additional price may provide a drive you can load up and send to them possibly to get started. Btw, ever wonder how data is stored at these sites? Do you think they have exactly one copy on a single drive or are they running perhaps RAID with tape back up? Something to think about.

2) understanding a sense of risk management. Imagine copying data from one drive to another and the 2nd drive in the equation fails to do it correctly. This is a flawed back up. Now consider mirrored drives that as some call it - RAID. Has the probability of a data copy flaw increased over a one drive scenario? The flip side is complete drive failure. What is more likely to save your data - two drives with identical data or one drive?

3) independent copies - you can always copy to more than one drive and if savvy enough make sure the settings are so that the target drive is relative to the home drive (software will check to see if it has properly copied the files over).

4) What is not discussed and should be is that fairly static data can be archived safely to higher end discs - CD and DVD material. There are specially made discs that will last in a reasonable environment over 20 years. These are not your K-Mart write discs but designed for long life. I cannot comment on blu-ray as I have no experience on them for archiving data. This option is a very good one as not only can they last a long time but easier to take off site.

Just more peanuts from the gallery. FYI I do asynchronous mirror backups drive a to drive b, verify, then b to c, verify.
 
phrehdd said:
The easy part -

1) use something like Crash plan or similar. Just be aware to get started may take some doing if you have a lot of data and most home internet upload is relatively slow. They, as someone else mentioned in a similar mode of discussion for an additional price may provide a drive you can load up and send to them possibly to get started. Btw, ever wonder how data is stored at these sites? Do you think they have exactly one copy on a single drive or are they running perhaps RAID with tape back up? Something to think about.

2) understanding a sense of risk management. Imagine copying data from one drive to another and the 2nd drive in the equation fails to do it correctly. This is a flawed back up. Now consider mirrored drives that as some call it - RAID. Has the probability of a data copy flaw increased over a one drive scenario? The flip side is complete drive failure. What is more likely to save your data - two drives with identical data or one drive?

3) independent copies - you can always copy to more than one drive and if savvy enough make sure the settings are so that the target drive is relative to the home drive (software will check to see if it has properly copied the files over).

4) What is not discussed and should be is that fairly static data can be archived safely to higher end discs - CD and DVD material. There are specially made discs that will last in a reasonable environment over 20 years. These are not your K-Mart write discs but designed for long life. I cannot comment on blu-ray as I have no experience on them for archiving data. This option is a very good one as not only can they last a long time but easier to take off site.

Just more peanuts from the gallery. FYI I do asynchronous mirror backups drive a to drive b, verify, then b to c, verify.
Click to expand...

What about my diagram? Do you think that will work?
 
MacOG728893 said:
What about my diagram? Do you think that will work?
Click to expand...

Yes it 'can' work.

I know of one person who has her external library of files on two different drives. She uses on directly and then has it cloned incrementally to the other drive. The latter of the two is used for the backup via Internet to the service she uses. I thought it peculiar but actually there is a logic to it - the first drive gets all the data and is "active." The 2nd drive only is active during incremental cloning of the first drive and thus is less frequently used and more available for on line back up service. Given the price of drives, I guess she did her self proud.
 
I do things as simple as possible.

i buy a USB powered 1TB drive, do my backing up and then unlpug and store it. I include a print out of the projects on the drive and any details I may want (I also keep a .doc file on the hard drive itself).

I use the USB powered ones so I don't have to worry about losing a power supply.
 
phrehdd said:
Yes it 'can' work.

I know of one person who has her external library of files on two different drives. She uses on directly and then has it cloned incrementally to the other drive. The latter of the two is used for the backup via Internet to the service she uses. I thought it peculiar but actually there is a logic to it - the first drive gets all the data and is "active." The 2nd drive only is active during incremental cloning of the first drive and thus is less frequently used and more available for on line back up service. Given the price of drives, I guess she did her self proud.
Click to expand...

How does this solve the slow upload speeds to the online backup service? Uploading to the backup service does not make the drive slow, the process that is slow is uploading the files through one's ISP.
 
MacOG728893 said:
How does this solve the slow upload speeds to the online backup service? Uploading to the backup service does not make the drive slow, the process that is slow is uploading the files through one's ISP.
Click to expand...

I have mentioned that services are good if you want/need them and it is the initial upload that is slow. After that, you simply add to your on line service back up specific files.

Ideally, you either have a fast upload capability, do a very long (could be into days) first upload or -

Send the first round via a back up drive/media that they can do at their facility.

You may also want to talk to your service provider to find out if there is a way to get a faster upload speed for a month (pay for it) as a test. You can always decide not to go with the plan to increase your upload speed.

I think a better answer would be to ask here directly those who use such services how they managed to do their first upload/backup. In the meanwhile, I'll check with the gal I mentioned before to find out what it took for her and possibly which service.
 
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