Noob Question - Why do you have to constantly backup RAID setups?

[Drizzy]

I have never had one but I am trying to learn more about RAID setups to see if it is what I am looking for. I dont understand why you have to backup your data constantly though. Can you just have another HD in your computer that you backup to? Like run 2 RAID HD for your OS and stuff and have 1 HD that is not in RAID format?

 

[johnjkr1]

Your question depends on what kind of raid your talking about. If your talking about "striping", backups are VERY important. You now have twice as many drives, and if one fails, all your data is shot. And yes, you can have an extra hard drive to back stuff up to that isnt part of the stripe.

 

[Drizzy]

If you dont do "striping" do you still get the additional speed from having it in RAID format?

 

[Rotax]

typically, no, because striping isn't really even RAID, its more so AID, there is NO redundancy. . with a 'mirroring' setup you write to both drives thus have a "backup" automatically (not that a HD is way of "backing up") . . but mirroring is also slower due to having to write to both drives at once . .

striping=speed
mirroring=redundancy

 

[GoSharks]

you still want to backup your data in a raid array becuase a number of things could happen which will cuase you to lose data. they do not include hard drive failure, but could include: viruses, user error, complete system loss, etc.

 

[0roo0roo]

look itup on storagereview.com there are many types of raid, including raid 5, raid combinations of 0+1.. etc. whether a mirrored setup is faster depends on how smart the card is. write speed will not incrrease with mirror, butr smart cards can read off two drives faster then one.

 

[Jeff7]

Originally posted by: Rotax
typically, no, because striping isn't really even RAID, its more so AID, there is NO redundancy. . with a 'mirroring' setup you write to both drives thus have a "backup" automatically (not that a HD is way of "backing up") . . but mirroring is also slower due to having to write to both drives at once . .

striping=speed
mirroring=redundancy

Or the nifty RAID 5 - some of both. Check the Anandtech FAQ for info on RAID levels.

 

[DaveSimmons]

RAID 1 and 5 help keep a system running if a drive fails but offer NO protection against:
- bad power supply that kills 2 or more drives
- fire, flood, lightning, theft
- disk controller problem that corrupts the drives
- virus / worm / trojan that alters files
- program bug that alters files
- operating system bug that alters files
- human error (oops! did I just delete the database folder?)
- disgruntled employee (haha! I just deleted the database folder!)

 

[Sideswipe001]

Originally posted by: DaveSimmons
RAID 1 and 5 help keep a system running if a drive fails but offer NO protection against:
- bad power supply that kills 2 or more drives
- fire, flood, lightning, theft
- disk controller problem that corrupts the drives
- virus / worm / trojan that alters files
- program bug that alters files
- operating system bug that alters files
- human error (oops! did I just delete the database folder?)
- disgruntled employee (haha! I just deleted the database folder!)

It does offer some protection. There is nothing that's fool proof. Even tape backup isn't going to save you from fire,flood, lightning, if where the tapes are gets hit too. But it's easier to restore a RAID 5 array when a disk goes bad, or a RAID 1. They are for different things.

 

[Matthias99]

Even tape backup isn't going to save you from fire,flood, lightning, if where the tapes are gets hit too.

Which is why anyone serious about backups uses secure OFFSITE backups on a fairly regular basis.

The point is that the average user is more likely to suffer from many of the items in that above list than a hardware drive failure, especially human error and virus damage. So *just* having a RAID1/RAID5 array (without backups of some sort) is never really enough protection.

 

[DaveSimmons]

Exactly -- most people with just one loss-prevention strategy (instead of multiple) would be better off using external drives that they stick in a closet than with RAID. As long as they used it of course -- RAID 1/5 would be better than nothing if they lack the discipline to manually back up on a regular basis.

 

[EeyoreX]

The level/consistancy of backups with a RAID array should be no different than that of any other hard disk-based backup regimin. Single hard drive or RAID, any data you want saved should always be backed up. Period.

\Dan

 

[0roo0roo]

Originally posted by: Matthias99

Even tape backup isn't going to save you from fire,flood, lightning, if where the tapes are gets hit too.

Which is why anyone serious about backups uses secure OFFSITE backups on a fairly regular basis.

The point is that the average user is more likely to suffer from many of the items in that above list than a hardware drive failure, especially human error and virus damage. So *just* having a RAID1/RAID5 array (without backups of some sort) is never really enough protection.

i don't see it that way. most users i know lose most data through harddrive failure. user errors might f*ck windows a bit, but most data survives. virus scanners are pretty common these days. but most everyone i know has had one drive or more fail. raid would prevent this. and not to mention, most people don't backup manually all that well.

 

[beatle]

Originally posted by: 0roo0roo

Originally posted by: Matthias99

Even tape backup isn't going to save you from fire,flood, lightning, if where the tapes are gets hit too.

Which is why anyone serious about backups uses secure OFFSITE backups on a fairly regular basis.

The point is that the average user is more likely to suffer from many of the items in that above list than a hardware drive failure, especially human error and virus damage. So *just* having a RAID1/RAID5 array (without backups of some sort) is never really enough protection.

i don't see it that way. most users i know lose most data through harddrive failure. user errors might f*ck windows a bit, but most data survives. virus scanners are pretty common these days. but most everyone i know has had one drive or more fail. raid would prevent this. and not to mention, most people don't backup manually all that well.

The thing is, most enthusiasts are keen enough on file management not to delete something or leave yourself open to a virus, so RAID 1 is a good idea. The problem is, setting up a backup solution that isn't "automatic" like RAID 1 is requires some effort and knowledge that your average user won't have and/or may not want to deal with at all. Remember "average" doesn't always refer to your average AT member. 😀

 

[Matthias99]

Originally posted by: 0roo0roo

Originally posted by: Matthias99

Even tape backup isn't going to save you from fire,flood, lightning, if where the tapes are gets hit too.

Which is why anyone serious about backups uses secure OFFSITE backups on a fairly regular basis.

The point is that the average user is more likely to suffer from many of the items in that above list than a hardware drive failure, especially human error and virus damage. So *just* having a RAID1/RAID5 array (without backups of some sort) is never really enough protection.

i don't see it that way. most users i know lose most data through harddrive failure. user errors might f*ck windows a bit, but most data survives. virus scanners are pretty common these days. but most everyone i know has had one drive or more fail. raid would prevent this. and not to mention, most people don't backup manually all that well.

You evidently know some remarkably unlucky and smart people. I've worked in tech support for a LARGE company, and the vast majority of problems we dealt with were due to user error of some sort. I can't recall seeing more than half a dozen hard drives die in two years for ~1000 workstations (there were others that arrived DOA, or had problems discovered during installation and setup, but once they were up and running they very rarely failed). I haven't had a personal drive fail in 10 years, although I don't think I've ever kept a single drive for more than 2-3 years, either. Modern hard disks (barring a few exceptions, like IBM's Deskstar line for a while) are just very reliable.

The level/consistancy of backups with a RAID array should be no different than that of any other hard disk-based backup regimin. Single hard drive or RAID, any data you want saved should always be backed up. Period.

\Dan

But a RAID system doesn't protect against data loss/corruption, or catastrophic physical damage to the machine (lightning strike, fire, flood, etc.)

I do agree with your conclusion, though; I work in the storage industry. You need to back up your data, even with a RAID setup. There are just too many things that can go wrong.

 

[suklee]

I want to inquire about the possibility of using a RAID 1 setup on a remote mail server.

The mail server will be processing mail using MDaemon for about 15 users. P4 1.5GHz, 256RAM, 20 gig hard drive.

Traditionally, users have been using POP3 to download mails onto their workstation, but I feel it's time they change to IMAP and have mails centralized on the server to facilitate backup (which is and has been non existant for the past few years).

Besides adding at least another 256MB ram, the storage space needs to be improved. At the same time, I've got to consider my backup options. I've thought of two :

1) External hard drive
2) RAID 1 setup

RAID 5 crossed my mind too but it's much more expensive than either of the above two options, no? As this is a remote office with basically no IT support, I figured the 'automatic backup' aspect of RAID1 would be beneficial... say, throw in 2 x 160GB hard drives in there.

Would RAID alone be sufficient? Or do I simply forget RAID, go with one HD and back it up to an external source and store offsite? Any other suggestions will of course be greatly appreciated.

Thanks in advance. 🙂

 

[tweeve2002]

RAID 0 is my favorite RAID....Nice and fast...just make sure you do back up every one in a while....I lost my RAID once to a Bad PSU, it didnt supply enough power to the computer anymore and the RAID quit....lost over 180GB of data on my 223GB RAID...now I back up with another RAID 0 setup...2 RAID 0 setups in one computer....I figure that If one drive dies I still have the back-up, if two drives fail, well Im screwed.

 

[Batti]

As an example of what can go wrong, we had a highly redundant SAN at work with 48 fiber channel drives, redundant raid controllers, redundant fiber paths - the works.

A drive failed. During the failover of the data to a spare drive, the raid controller failed. Instant scrambled data!

That SAN was a Dell, it's now scrap.