I've purchased a CineRaid CR-H458 unit which I will be setting up as RAID1 (which I understand simply duplicates the data across 2 drives. I just want it for redundancy.
I have two questions:
RAID1 would be best for my purpose, right? So if one drive fails I only lose the drive and not the data since it's duplicated, right?
If RAID1 is the best for my purpose, what's the recovery process if one drive fails? Can I just pull out the good unit and copy the data to a new backup drive? Do I simply plug in a new drive for it to "rebuild" the array? Unfortunately their manual is a piece of paper showing diagrams but no details about recovery. And I can't find a forum on their site either.
[Stephen Pickering]"RAID1 would be best for my purpose, right?"
CR-H458 is a four-drive unit; do you plan to use just two drives for one mirror, or?...
With four drives, RAID5 might be better; it's less reliable than RAID1 though.
[Stephen Pickering]"So if one drive fails I only lose the drive and not the data since it's duplicated, right?"
Correct. Doesn't protect against user error or file system corruption (most common causes of data loss) though, so backup is still paramount.
[Stephen Pickering]"If RAID1 is the best for my purpose, what's the recovery process if one drive fails? Can I just pull out the good unit and copy the data to a new backup drive? Do I simply plug in a new drive for it to "rebuild" the array? "
The specs say "Auto-rebuild in RAID 5 mode" which I assume means, "no auto-rebuild in RAID 1 mode". You'll have to do it manually through the supplied RAID manager utility: replace the drive, start a rebuild.
as Alex said, I would recommend Raid 5. Better data speed than raid 1, auto rebuild function, it's only a 4 drive raid, so in case of redundancy one drive can fail - this means it's pretty safe. More space on the raid with level 5.
You should have a seperate back-up (USB Hardrive) anyway.
Mac pro 8core
several raid systems
Thank you for your responses. RAID 5 might be better for me. I decided on RAID 1 for some reason when researching this. I think it might have been because I was thinking about an external harddrive to backup the RAID for offsite storage. I'm planning all 4 drives in the box to be 4TB drives. I was thinking I would have two sets of RAID 1 which would give me 8TB of total space, plus make it easier for offsite storage (2x 4TB external drives).
RAID 5 with 4 4TB drives would give me 12TB of storage and increased speed, right? That would be nice but then it might be hard to put together a 3rd redundant backup using external drives. What's the reason RAID 5 is less safe?
[Stephen Pickering]"What's the reason RAID 5 is less safe?"
Chances of drive failure or corrupted data during rebuild are higher than with RAID1, and in some cases (16TB RAID5 sets with desktop drives) are high enough so that people don't recommend them unless the user understands the risk.
It's terribly true!
What can we do against it?
First of all - we use the best drives you can get (enterprise class drives)
If you are able to: we use Raid6 (up to two drives can fail) plus one spare (automatically jumps in, when you have a disc failure)
Complete Data Back-up on a USB Drive.
2. Complete Data Back-up on a USB Drive stored within a different building.
External power supply (USV) so you can shut down properly your computer and raids in case of power failure.
After 5 years 24h use of the raids (around 50.000 working hours) replace your drives within a raid.
If you do it this way, a complete data loss is nearly impossible.
Mac pro 8core
several raid systems