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Q regarding Raid Mirror

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April 23, 2009 9:09:32 AM

Hey. I've heard that some controllers or systems use all drives in a mirror (raid 1) for reading - upping the sequential read speed considerably. I know that isn't true for my parents old promise controller on their p4c800, but is it for newer chips? if so, is there like a list of motherboards with that capability, or list of chipsets with it in?
I'm considering giving my parents a new pc, and since they've lost their data to faulty harddrives many times, I'd like to run 4x500GB drives in raid 1 so I can be sure they won't break down again. Currently they're running two seagate 160gb drives as system (raid 1 too), but ofcourse one of them broke down the other day, so I think that's got to be top priority.

ps. I won't have to build it until mid june or so, thus chipset for am2+ or based on non quadcore intel isn't important.

More about : raid mirror

a b G Storage
April 23, 2009 11:54:24 AM

They need a good backup program, and back up to an external drive.
I have said it before, and I will say again, RAID Mirroring is a very poor form of a backup, no matter how many drives you have. The only thing mirroring will protect you against is a drive physically failing. Nothing else. Most data lost is caused by things other than a failed drive.
Accidental deletions, Virus, Malware, controller failure, software/data corruption, lightening strikes, power surges, on and on. A mirrored set of drives gives you zero protection from all these things. A mirrored drive array is meant to keep a server up and running until another drive can installed, that is benefit of mirroring.

If you believe a mirrored array will protect you from data loss, you are a fool, and you will live to regret using a mirrored array as a backup.

Back up to a USB drive, unplug and put it away, only reconnect to update.
If you data is extremely important, burn it to DVD.
April 23, 2009 12:53:40 PM

At which point did I indicate I needed a lesson on the purpose of mirroring? Or indicate that I don't know what it does or does not protect the system from?
ps. it does protect from controller failures actually. A non raid controller will just ignore the raid structure data. But the point is - I need an answer to my question, not some smartass info on what to do on top of running raid.

My parents are a bit foolish from time to time, but in the entire history of them having a computer, they've never once deleted something they needed. I trust they'll keep that record up, and I know they from time to time make a backup of what they think are important things. However, what I think is important, is not having to reinstall their system every 3 years because of a fu<king harddrive failing.
And 1) I happen to have some 500gb drives spare. 2) I've tried at work having two 1tb seagate server drives fail within a 2 day timespan. So I want at least 3 drives in a mirror to make sure work's problems don't follow me home.


Edit: Anti freedom of speech system kicked in and ate half the post. Reposting.
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April 25, 2009 2:45:18 AM

neiroatopelcc, I'm on your side. I don't know a single person who has lost data due to anything other than a dead drive. I grew up with my mother as the #1 Commodore 64 seller in the midwest and she and my uncle taught computer classes. So, I've been around computers my entire life.

However, backing up is essential for important data as other problems can happen. I experienced a corrupted partition on a Raid 5 array but had no problem getting my data off that Raid array. There are numerous programs to fix software errors in addition to accidental deletion. If someone gets a bad virus, its there own fault for not having protection and/or downloading junk. As far as power surges, I've seen many PCs damaged due to lightning and surges but they were always confined to the network card.

I'm not going to add to the backing up discussion and potential problems any more.

But I will add that the most you can do with certain Raid controllers in Raid 1 is use 3 drives. Its called Raid 1E and used by LSI and others. For a 4 drive Raid you can do a Raid 10(1+0) where it takes 2 sets of Raid 1 and stripes data across both. You might be able to do this on their PC but chances are you will need to buy a PCI hardware Raid controller as most pre-built PCs don't offer Raid. Chances are if they do offer Raid 1 only, that its a junk Raid controller and you would be doing more harm than good by using it. Raid 10 allows for up to 2 drives to die at the same time. This is what I use in all my PCs and I just had a drive die a few weeks ago, and I haven't lost any data or downtime.

You should see if their PC can even do Raid first and what Raid levels if any. One way of doing this is downloading Intel's Matrix Storage program if their PC is Intel based. If it is, this program will be able to tell you the number of ports available and if you can create a Raid array. Or you will need to open the PC and see if there is a PCI or PCI-Express slot open for a hardware Raid controller.

Another option is to get an external drive and Acronis backup software. You can set it to do an initial backup of the entire disk, which creates an "image" and then backup every week only the data that has changed. You can also create a special restore partition on the Raid 1 array. You can do all of this so it would be very easy to restore the image should all of the drives fail at once.

If your parents are like other people 40 or older, needing more than a 2 drive Raid 1 is not crucial. They don't "explore" the web like younger people do. Just make sure they are protected by Kaspersky, Webroot, Antivir or NOD32. Norton, McAfee, AVG and others are not good at all. I learned how much Norton sucked the hard way, but I didn't lose any data or need to reinstall after having over 30 infected files. Check out this site:
http://www.av-comparatives.org/comparativesreviews/main...

Good Luck.
April 25, 2009 8:49:30 AM

Thanks for the reply, but I might've wanted to mention that I know the various types of raid. I must confess I didn't know raid 1 only took two drives. But then I've never used it with more in the past. I know raid 01 and raid 10 ofc, but most controllers only offer raid 0, 1 and 5 these days, so that won't be an option.

ps. in the last 10+ years that I've worked IT at a school, I've had a total of 3 incidents where I had to get data out of a backup because of user error. So it does happen, but it's just so damn unlikely. Dead drives and similar killing data is quite common though, ye.

"They don't "explore" the web like younger people do. Just make sure they are protected by Kaspersky, Webroot, Antivir or NOD32. Norton, McAfee, AVG and others are not good at all."
My parents are definetly old enough to be in the group where you'd think they wouldn't go explore. But you're wrong. My parents don't visit the same sites kids would, but they still visit dangerous sites. Even my grandma visited something where she got spyware on her pc the other day. I don't remember her age, but grandpa was 82 or 83 when he died a few years ago .... so she's over 40 too :) 

I've used kaspersky on 15 computers (private) since 2006, and so far I've only had a single incident with that. It's great really. Nothing's perfect, but kaspersky can be set up to think for the user, so I don't have to go fix family computers all day.

Anyway, you didn't answer my actual question - ie which controllers, if any, offer improved read speed in raid 1.


ps. I've used imaging tools since '98 for work, I know how to make an image :) 
wds is not the best imaging system btw.
a b G Storage
April 25, 2009 4:18:34 PM

most good onboard controllers will support RAID 5. It wouldn't be as fast as other RAID options but would result in the least amount of space lost and be the most practical choice for you. IMO
a b G Storage
April 25, 2009 4:24:09 PM

I'm with Jit. RAID1 isn't the way to go. If you don't like having to reinstall everything, use those imaging tools you talked about. I would be spending time trying to figure out why drives are dying over there then trying to figure out which chipsets support multi read on RAID1 arrays. RAID1 != backup. Implement a backup solution, image the fresh drive so you don't have to reinstall everything when it happens again, and start trying to figure out why the drives are dying. (Check the PSU voltage levels.)
April 25, 2009 4:54:03 PM

Why does everybody want to tell me stuff I'm not asking for, yet nobody answer my question?
April 25, 2009 7:10:45 PM

Well, I'll give you at least try one direct answer.....LOL

While certain controllers will improve sequential reads while in RAID 1 ( 3ware twinstore cards comes to mind ), this feature for some reason is not advertised as much as it should be on most controller cards, so only testing will tell. More importantly however, is most controllers have another benefit to RAID 1. The ability to not increase a single sequential access, but to handle multiple simultaneous reads at native individual drive speeds. This is because the heads can and do move independently of each other on all reads. This will greatly improve multi-tasking on system drives and is arguablly more important than sequential performance.

As far as all the uneeded advice/education ?.....This has always been a common problem with forums in general, as most answers are just buying suggestions, and not actual solutions. Getting angry over this will not help your case, as most people here tend to just follow the latest trend anyhow...i.e. buy newest/hottest item out right now, and all your problems will be solved. There are many people here who will go out of there way to actually help solve a problem, but there are also a great number of people here who's expertise lie in gaming system builds. No need to throw a fit, just ignore the replies that don't pertain to your situation. If I wanted to build a gaming rig, these very same people who are annoying you, would probablly offer the best suggestions.

I happen to consider myself somewhat of an expert on RAID, yet that is just a specialized area and I regularily seek out help here in other areas. I almost always give my OPINION, such as "avoid RAID 5 like the plague", but that's outside the purvue of this thread right now, so I contain myself.

Hope this helps.....If not just ignore it as suggested....
April 25, 2009 8:01:25 PM

Really? I didn't know that other part abotu raid 1. Guess it's just a matter of trying it. As for raid 5 - it's okay if you use drives intended for 24/7 use - but using desktop drives raid 5 is horrible.

Anyway thanks for the info.

ps. I'm one of the gaming rig builders actually, but I don't usually offer advice people don't appear to want.
Suppose I overreacted though, but I'm a bit tired of getting all kinds of answers that I didn't look for. I may make mistakes from time to time, but I like to consider myself adequately skilled in this stuff to not need to be questioned about my decisions. So it's kinda an insult when people almost 'demand' that I use backup utilities of their choice, or a different storage solution altogether. Dunno if you know what I mean?
April 25, 2009 8:16:34 PM

Only reason why I replied on that part, is I myself have been there many many times and know the frustration....my builds are always odd ducks, and I typically spend more time explaining why I actually own the hardware, than the problem at hand. So yeah....I know exactly what you mean..LOL

I know 3ware's Twinstor works great on there older cards ( i had a 7504 PCI-X for awhile ), but haven't used them since. It's designed to do exactly what you want and may be worth checking out.
April 25, 2009 8:20:09 PM

Thanks. Will look into that ... once I've completed a couple more missions in saints row :) 
April 25, 2009 11:04:15 PM

Just to add another $.02 and since I forgot that you originally asked about Raid 1 performance.

Its called "Split Seeks" where the OS can read from both drives at the same time. Not all Raid controllers can do this - usually only the cheap ones cannot. However, Intel's onboard Raid controller can. Raid 1 won't provide much of an increase in throughput but can help in random access.

About Raid 10, I have never seen a controller that offers Raid 5 but not Raid 10.

Neiroatepoelcc, its nice to see someone who knows not to use desktop drives in Raid. I get in arguments all the time about this topic.

Good Luck
April 26, 2009 12:26:36 AM

yep specialk90...."split seek" is the term I just couldn't spit off the tip of my tongue...LOL....even the cheap ones I've used have had this feature to some extent. Sometimes it's restricted to small random IO tasks while sequentially reading from another on the low end ones I've played with.

Any idea why this feature is almost never advertised even on cards that support it fully ?
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