If not RAID, then what for backups?

O

ocme

Limp Gawd
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Jan 19, 2010
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I've been trying to come up with a solution for our business for storing data and I read that RAID is not a backup (1/5/6 etc) and a lot of folks are straying away from it. My question is if RAID isn't good then what is good for storage backups over multiple disks? If my wording seems odd I'm sorry, I don't have much experience in RAID but I am trying to figure out what is the best. Preferrably using 2TB or 3TB drives.
 
Backing up to RAID is fine, in fact most people would probably want the array to use some type of fault tolerant configuration.

IMO, RAID should be used for primary storage and backup storage. For boot drives RAID1 is a good choice, for data RAID 5 or 6 would be good choices. I would make sure whatever system you have has the ability to use hot spares.
 
RAID protects against disk failures but NOTHING else. That is why it is not good as the sole backup (IE you have RAID in your primary system and then think you are "backed up").

It is definitely good to use RAID as disk failures are one very common form of disaster that requires a backup. But you also need to protect against things like corruption, accidently deleted files, full hardware failures, etc. that only a separate backup medium will provide.
 
Raid is not a backup solution. What happens if an employee steals the whole server/computer?
How does the RAID on your hard drive that is now in the possession of said employee remain backed up?

Backup should be external device from where the data is stored.

And for a business where losing your original data is critical (e.g. what happens if your data center is struck by a hurricane or burns down or zombies eat everything) at least at some part of the backup strategy should also be offsite .
 
As other said, RAID isn't a true back up.
Its more like fault tolerence, and up time for your server, if the harddrive ever crashs.

normal server at places i worked.

Server (raid 1 with hotswap) ---> Internal backup server ---> External backup server
 
Backup OS and file repositories, sytemstates, etc. to a removable drive. I use a hotswap bay with 2x 3 TB HDDs. After initial backup, remove the drive, bring it to a safety deposit box and leave it for a month. (or what duration you would like.)

Set backups to save on the second HDD for 1 month. (or what duration you would like.)
After 1 month, (or what duration you would like.) before the next backup rotation cycle, remove the second drive, bring it to the safety deposit box and swap it with the 1st HDD.

Repeat backup rotation…
 
Grentz said:
RAID protects against disk failures but NOTHING else. That is why it is not good as the sole backup (IE you have RAID in your primary system and then think you are "backed up").

It is definitely good to use RAID as disk failures are one very common form of disaster that requires a backup. But you also need to protect against things like corruption, accidently deleted files, full hardware failures, etc. that only a separate backup medium will provide.
Click to expand...

^This
 
Yeah don't get us wrong, RAID is awesome. It's primary function is to provide high performance and minimum downtime from disk failures.

But from water damage, fire, electrical surge, human destruction, it will not save your data.
 
not sure why so many people keep saying "straying away from Raid" I think more companies are realizing the extra cash for a better Raid level say 6 or 50 vs the old raid 5 standard , yes i think raid 5 use is diminishing in favor of better levels of protection but i don't see raid going away as primary storage anytime soon

but its not your backup as mentioned
 
One question that no one has asked the OP is how much data do you need to backup, do you have any regulatory or insurance requirements as to the backup and/or storage of your data and how much is the data worth to your enterprise? What OS/FS types are you using? The gold standard of backup is tape. The more data you have to backup ( incremental and/or historical copies) the less expensive it gets per GB (TCO drive, tapes & support/service). As with any technology, there are pluses and minuses to any solution. How much data do you need to backup daily, do you have someone available to change tapes nightly (or weekly or more if you need a changer) and what is your top budget for this project?
As to the question of is RAID sufficient for backup, again it is a question of tolerances. Our backup workflow is DDT, which is disk to disk to tape. Nightly our servers (ZFS and various forms of both hardware and software RAID) back up different Hardware RAID6 based boxes (Over a 56Gb IB segment which is just used for backup) which is then in turn backed up to LTO4/5/6 changers.
 
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You can backup TO a RAID, just that using a RAID as your main drive array, while an excellent idea, does NOT double as a backup. If you have two separate RAID setups (like COMPLETELY separate) then you can use one as a backup, no problem. As long as your setup protects you in the ways you need, like if this is for enterprise with extremely important data that must never be lost, keeping two separate arrays in one building - even if on different servers with different controllers and drives - would still be susceptible to building fires or potentially closeby lightning strikes that aren't stopped by your power protection equipment, etc. A setup which is unplugged except during backup/restore operations is more safe with the lightning strike possibility, though still not completely safe as it could happen when it is powered up.

It all depends on how much protection you need, want, and can afford.
 
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