Comments on: Software Vs Hardware RAID

By: Bill

Bill — Fri, 02 Sep 2011 13:47:16 +0000

Hi,

I was thinking of creating the following RAID set on one of our powerpc xserves running 10.5 (non server). Curious if anyone has feedback on the configuration. I am just learning about RAID setups, and to this point I have been simply using RAID 1 on all our data to avoid drive failure issues. However we run a design firm and having multiple separate volumes can be annoying. So after reading a tiny bit I was considering the following configuration:

One RAID 0 stripped set (created using the raid feature in OSX disk utility).
Inside this Raid set I would add RAID 1 drives (like lacie 2big or WD Mybook II) that are mirrored, thinking 5 or 6. Not sure if there are any benefits to the number of drives one way or the other.

So it would be a combination of software and hardware. I like this idea because i could easily swap failed drives but also increase access speed. My one concern is the RAID 0 portion becoming corrupt and not being able to retrieve the data. Will I loose it all? It will be a lot of data to keep backed up.

I would love to hear any and all feedback! thanks.

Bill

By: keith

keith — Wed, 31 Aug 2011 11:10:47 +0000

I do not believe anyone here would seriously consider using a WINDOWS software Raid!
:-D

By: Rixkster

Rixkster — Wed, 27 Apr 2011 17:15:18 +0000

You said:
“…So which one is better software raid or hardware raid?
Short answer – None…”

Wow, Hardware is the only important answer, short, or long.

Dude, Dedicated hardware Raid is infinitely better than Software Raid.
You might as well say that your “1″ analog Modem/phone was fantastic until someone picked up the phone line -oops ?
In other words, if you lose your OS, you have a good possibilty of losing all your Raid -you just lost ALL your Data. get it?
I lost my OS completely, my Windows software raid got pffft’d, But luckily, I had my important data on a Hardware Raid 10 controller card.
After I swapped out for a new MB and re-installed OS, my hardware raid controller came up with flying colors -NO data loss.
-not to mention, that
1./ Software Raid is extremely “limited” on its Raid variations, and capabilities depending on the “robustness” of your OS, and also how deep is your wallet,
You wanna talk Windows software Raid, where all your eggs are in 1 Basket? , wasting CPU/Memory cycles ?, then just forget it -LMAO.
And, even then, you will defintely pay for “good” software Raid -in other words, you’re much better off getting a dedicated Hardware raid (HBA) controller.
BTW, Windows Sotware Raid, such as Windows 8 Sever, still comes in only 2 colors, (Raid 1, and Raid 5) -and you’re gonna pay for it $.
For that extra money -just buy the safety of a high quality dedicated hardware-raid controiller card /with the Cables….
:)
2./ Hardware Raid is blazingly faster than any Software/BIOS Raid garbage too -hands down.
3./ Don’t be silly, if your DATA is that important.

seriously,

Software Raid ? -get a grip will ya.

gzzz,

By: Andrew

Andrew — Fri, 01 Apr 2011 07:12:40 +0000

@ galvo, sound suspicious to me that both would crash at the same time. Are there other WORKING drives connected to the same controller ?? Just a thought.. Well i am from the old school of thought of thought that use only H/W raid. But i am starting to change my point of view on that and am going to change my current setup. ,, I am beginning to think my controllers are bottle necking my performance while i have (2) xeon 3.6 sitting doing nothing all day. I was just looking for an articale to reaffim my thoughts. When i set up my first S/Ware raid (12 fiber disc on my home PC) it was pretty fast. The only drawback i noticed was that the drives wined alot and sounded like machine gun fire or popcorn, even when just sitting there. Through the H/Ware raid they didn’t do that. The dont clicity klack on my server.. I got 2 seperate controllers in my PC and hardly make make any noise in there iether (h/w raid 0, 2chan x 3disc) I dont know. it will probably take me a week to figure out. Will probably go 0 – 0 and stripe or span through OS

By: Kris

Kris — Sat, 12 Mar 2011 07:32:01 +0000

@Galvao
This is recoverable. Each disk should contain exactly the same info (provided the software doing your RAID1 didn’t fail before this hardware failure, in which case one disk would be time stated to that point) unless they both completely failed (hard drive motor no longer functions and/or every head on the hard drive crashed and scratched the disk platters). This would be extremely unlikely for both to be failed at the exact same time. Unless there was a serious power surge that had gone through your entire system and reached both hard drives. EXTREMELY unlikely.

In any case, there are still bits that exist on the hard drive and for a high price there are data recovery centers that can place the platters in another hard drive encasement and read what is available. Provided the heads didn’t scratch the platters to severely, any data outside of scratched areas should be recoverable. Depends what the data is worth to you

Cheers

By: Galvao

Galvao — Thu, 27 Jan 2011 03:54:20 +0000

Hi,

My server Windows crash with RAID1 software. the technician said “the two discs stopped working” Is this possible? “we attach these drives to this server or to another server, the server’s BIOS does not recognize them”

I find it amazing that they can not recover anything.

I hope your comment

Thanks!

By: SSEGAWA DRRICK

SSEGAWA DRRICK — Fri, 04 Sep 2009 12:44:41 +0000

THANKS FOR THAT GOOD INFORMATION AND KEEP ON. DERRICK SSEGAWA KAMPALA UGANDA.

By: Jon

Jon — Mon, 27 Jul 2009 03:28:49 +0000

I've been using Software RAID for personal use for a while now and it's worked great. I have a software RAID 5 and RAID 1 under LVM. This is a great solution as I can mix different RAID arrays together to make the most efficient use out of my drives. For example, I have two 250gb drives in a RAID 1 and three 500gb drives in a RAID 5, with LVM I can make these two arrays function as one large volume. If anybody is interested here is a tutorial on How to Install Fedora 11 and Set up a Software RAID 0, 1, 5, 6 or 10 Array with LVM Great comparison, enjoyed the article, for home use software RAID is the best because of lower cost and increased flexibility.

By: Charanjit Singh

Charanjit Singh — Tue, 21 Jul 2009 16:09:41 +0000

Awesome friend whenever I visit at your site i always find some thing new tips and tricks. You are doing very good job this will encourage people for choosing open source as career. Thanks.

Regards
Charanjit Singh
System Admin, RHCT

By: Amr El-Sharnoby

Amr El-Sharnoby — Sat, 11 Jul 2009 16:37:31 +0000

Thanks, valqk ,

But for striping, LVM should be chosen, !

By: Harshad

Harshad — Thu, 09 Jul 2009 12:33:16 +0000

I personally feel if RAID is used along with LVM gives you much more reliable way of storing data without wasting any disk space.

By: valqk

valqk — Wed, 08 Jul 2009 17:27:38 +0000

I personally use Software raids (md linux and gmirror in fbsd). That’s because I can’t afford expensive models of 3ware and similar and also because you MUST have at LEAST 1 spare exactly the same one as the one in machine. I’ve bought 2 3ware 8006lp2. They work very good but unfortunately the speed test fails because they are SATAI not SATAII. The good thing is that they DO have HOSTSWAP and it WORKS!
(they are LOW PROFILE and dont have BBU). Funny thing is that I’ve read that there IS A WAY to do HOSTSWAP WITH SATA disk (as far as I can remember – detach the disk call hdparm to spin it off and then plug out, plug in the new one and call hdparm to spin it up again… never tested this!)
anyways. I’m for using both technologies but only if you have spare controller which is exactly the same as the one running, otherwise you’ll get in troubles some day. And this day will be the day that you can’t wait 5 hours to get a new hw raid card… :-D
@Amr El-Sharnoby here is why you should not use LVM2 mirroring.

By: Amr El-Sharnoby

Amr El-Sharnoby — Wed, 08 Jul 2009 13:35:24 +0000

I’d highly recommend that you consider using LVM striping and mirroring under Linux, that works like RAID-0 and RAID-1 allowing you to do all the magic of LVM ….

I’m using it for highly load servers with relatively new Xeon and Opteron CPUs and I can find its performance outperforming Modern Hardware RAID controllers with much more stability …

I’ve faced too much trouble with hardware raid controllers with those servers, the controllers caused too much instability and many failures , I’ve changed them, upgraded to newer models, updated firmware but all didn’t solve the problem,
so I’ve moved to LVM solution, as I’ve more than 30% idle CPU time even under high loads , while that LVM overhead is roughly 3 to 5% …
All problems has been solved, and I’m quite happy with tht stabilty and performance …

I’m using RHEL 5.3 on those servers ..

By: Vivek Gite

Vivek Gite — Wed, 08 Jul 2009 13:21:42 +0000

@Raja,

I only use those 80GB to backup data once a day.

There is rss comment feed for each page (just click on rss button @ firefox awesome bar). Nevertheless, I will add a subscribe to comments plugin as well.

By: Raja

Raja — Wed, 08 Jul 2009 13:09:17 +0000

Sorry for the extra spam, but i think a subscribe to comments plugin will allow people to turn this into a semi discussion.

By: Raja

Raja — Wed, 08 Jul 2009 13:07:58 +0000

Awesome write up man. Just a question, dont you think those 80GB hard drives eat up power?

@Solaris thanks for that nice quasi-hack on testing drive throughput :)

By: Cristiano

Cristiano — Wed, 08 Jul 2009 13:02:28 +0000

I agree with the author. I do too use software RAID for a couple of years and been really satisfied with it.

FYI: Cosmin, I suggest u to use mdadm for your array solution and mount the partition at startup. If you need any help, ill be glad to assist u… Just send me an e-mail.

By: mdm

mdm — Wed, 08 Jul 2009 12:05:30 +0000

Nice.

finally found what I have been looking for sometime..

By: t13nr4

t13nr4 — Wed, 08 Jul 2009 11:33:10 +0000

thanks for the info!!

By: Cosmin

Cosmin — Wed, 08 Jul 2009 10:55:28 +0000

have been using software raid1 on CentOs 4.5 but find it hard to manage, every kernel upgrade can break the array and drivers are not too good also this not tested on CentOs 5.
lately we switched to hardware raid but there are also somme issues between raid1 array on 15K and jbod on 10K.
so not found yet the solution that would be good for us.