• Some users have recently had their accounts hijacked. It seems that the now defunct EVGA forums might have compromised your password there and seems many are using the same PW here. We would suggest you UPDATE YOUR PASSWORD and TURN ON 2FA for your account here to further secure it. None of the compromised accounts had 2FA turned on.
    Once you have enabled 2FA, your account will be updated soon to show a badge, letting other members know that you use 2FA to protect your account. This should be beneficial for everyone that uses FSFT.

RAID info Sticky?

R

rodsfree

[H]ard|Gawd
Joined
Dec 13, 2004
Messages
1,417
I've noticed that a lot of people have posted asking for information on RAID. Myself included.

Is there anyway that we could get a sticky aimed at answering these questions?

I'm not asking for complete guides to the secrets of RAID, but just some basic definitions and FAQ's sorta thing.

And maybe another sticky on building an at home file server. The RAID card manufactures and all the links that the gurus pop up with when someone asks these questions.

I personally would love some guides on software RAID setups... I know Tom's Hardware has done a guide for Windows XP Pro, but I'd like to see the same type of info for a linux fedora setup (a copy of XP Pro cost almost as much as a RAID card does). Something to give me an idea of which OS I'd want to use for a software RAID setup.

I want to learn about RAID. I want to, eventually, have my own file server on my home network, to handle the storage of movies and to act as the storage location for my disk images, automated back up storage location and to store the files that I don't want to ever lose... like my digital photos of my grandchildren.

Just a thought...
Thanks

 
on your last point, raid is not a long term storage solution. The only way to guarantee those photos is to put them on a high quality photo paper, with a quality printer.
 
I tried for one ;) , before I was a mod, when I started the [thread=874828]Truth about RAID[/thread] debate. While I was not entirely correct, it did get a lot of info out there, amass nearly 2000 views, and help put to rest many of the misconceptions for at least some of our members.

However, many members still post here wanting help with RAID, seeking a performance increase with RAID-0, protection from loss with RAID-1, or huge capacity and protection from loss with RAID-5. All of these goals are much more compelx to achieve than members would first believe, if not impossible.

I will not start another debate on the merits/faults of RAID-0, as it does not answer your question, but I will throw some stuff out on the fault tolerant RAID levels, as that is what you are interested in.

Let's talk about your situation, and some weaknesses of RAID.

We'll say you get a hardware managed RAID going, let's say 4 drives in RAID-5. What happens to the data on that RAID, including the movies and photos you identified in your OP if:

1) Your power supply short circuits/fails catastrophically, damaging 2 or more of the drives in the array beyond recovery?
2) You accidentally repartition or reformat your RAID?
3) You accidentally delete and overwrite a file on the RAID that you really meant to keep?
4) Your system gets a virus or some other form of malware that trashes your RAID?
5) You have a flood or other natural disaster that destroys the computer with your RAID in it?
6) One of the members of the array fails during a rebuild caused by the failure of a different member?
7) You accidentally create a new RAID array on the drives?

My point: RAID is no protection against data loss, it only protects up time. It is no replacement for backups. Backups on a routine schedule. Backups stored in multiple off-site locations. Backups that are readily restored. Backups that can be stored for years if need be. Backups will protect your data against the causes of loss I listed above. RAID will not.

RAID is great for servers where uptime must be 100% - but noone trusts it with data, at least noone who cares about that data. It does nothing for desktop/home users that are not overly concerned about how much uptime their system enjoys.
 
Doug....
Lets look at some of your points....
All of them apply to not having a RAID system at all, even more than having one. Most of them come under the "Acts of God" or "Acts of My Own Stupidity" clauses, and I've had more than my share of both. ;)

I know that RAID is not a backup option for the system that the array is on...
I know that it's not a permanent backup solution...
My photos and the really important data get burned to CD/DVD as often as I can.
But it is a lot safer place to store a disk image of my personal system's HD than none at all. And it is just getting ridiculious to try to image a 200Gb hard drive to CD's or even DVDs.
I've got several computers at home. I've got several grandkids and an almost computer illerate wife. I've had to reinstall Windows on those computers way too often. I want a means of putting those computers back the way they were as quickly and as painlessly as possible. And disk Imaging is it... I've got Disk Image Pro v7 and it will let me automate the backups of these computers, if I've got a network drive big enough for the image to be written to.
Also, Have you priced a SCSI tape changer lately? WOW!
I can build several arrays to do what I want for the cost of one of those.

Also, there have been several articles in the past talking about using cheap, high capacity hard drives as backup media. Copy the files to them and remove them from the system. Life expectancy of the data is about 10 years, if nothing hapens to them. Which goes back to quite a few of your points - but it also applies to your tape media also. Or any magnetic media, and even the rewritable opticals.

The comment about protection against data loss....
Well it does protect you if you have files stored in 2 locations right?
Lets say my wife's computer has all of her recipes on it. My grandkids come over and start playing on her computer. They don't touch mine. They accidentally trash her hard drive. What happens? I just restore the disk image that was made several days ago and copied to the server. All that's lost is the data from those couple of days. They can't get to it on the server, but I can. So, it will protect me from data loss caused by my or someone elses error.

Is this statement correct? "The reliability of the RAID5 array is greater than that of a single hard drive."
If it is then I'd be safer using an array than just having a single big drive to act as my disk image storage location.

So...Where does that leave us?
For me, my situation, a RAID5 array on a file server that is large enough to act as a storage location for my other computers, seems to make sense. I'm not worried about mission critical data. I just want a cheap, relatively easy, somewhat safer, file storage and backup solution for my multiple PCs. Which I don't have anything but a DVD burner right now and an external USB drive that is smaller than the hard drive on my wifes computer.

Example....
I've got enough spare parts to build a computer. 1.8Ghz P4(socket 423)
I can buy 250Bg hard drives for $125.00 or there abouts. your example 4X $125.00 = $500
I have a Promise ATA100 add-on card... That'll give me 8 IDE ports on this PC.
1 old Seagate 20Gb for the OS - it's just laying around on my desk.
After it's setup it doesn't need CDROM, Floppy, monitor, keyboard or mouse... UltraVNC
Set it up as a Software RAID5 Array in Linux.... cost time and the learning curve, but no bucks.
Let it fold when it's not acting as a very slow file server. It doesn't have to be fast for my purposes.
For about $500.00 I'll have an array that i can use as NAS(Network Attached Storage) to act as a disk image storage location for my other computers and as a folder.( I'll have went from no backup option to this... so I'll have doubled my reliability, right?)


So...
Any other recommendations on how to accomplish what I want to do? And do it cheaper?

 
No, you've got it. Use RAID-5 to ensure upptime and availability, backup to CD/DVD the stuff you can't reinstall - you actually proved my points.

If you wanted too, you could recreate those images - it would just take much longer than rebuilding them from RAID. In the case of the system images you have, RAID will be an uptime tool, not a backup tool, precisely what RAID should be used for.

However, you also recognize my points about your truly irreplaceable user data - the family photos etc. Uptime isn't a big deal there - it only takes a few minutes to copy them back even from an optical disk. What does matter is the protection of that data, which you are quite aware is only provided by a sound backup stategy, not RAID. At least from what I read, we agree there.

I was only addressing concerns about your photos, etc. For your system images, RAID-5 is a great choice for storing them. You want to be able to bridge a hard drive failure and keep the system hosting them online. Protecting the data from some potential causes of loss is gravy there. Once again, looks like an agreement.

Seriously, we're not that far apart. Also, since you are backing up over a network, and unless all of your machines are on GbE (which I doubt) you can get by with most any bargain basement RAID-5 system, even software RAID - you will be capped at 100 Mbps transfers anyway. Get yourself some Seagate Barracudas, a RAID-5 card in the league of HighPoint, and image away. Good luck!
 
Actually I want to go to Gbe for my little network....
The NICs are getting cheaper ($20.00 range) and some of my motherboards have them already.
Whats stopping me is the cost of the switch.They are still a little higher than I want to pay($100.00 for 5 ports). :(

So...
Back to my little network...
The RAID5 (software or cheap hardware) server seems to be the cheapest solution for what I need.
I think we're in agreement on all of our points.
I think where a lot of people have problems is that they get the idea that RAID is a panacea for ALL of their problems. It's not.
But there are places that it makes sense, even for a small at home network.

Thanks,
 
You must log in or register to reply here.
Back
Top