Comments on: RAID 5 vs RAID 10: Recommended RAID For Safety and Performance

By: Scott W

Scott W — Sat, 04 Feb 2012 00:01:47 +0000

Jason,

If you put unencrypted data in the cloud you are asking for issues, to those of you who do, good luck with that and I hope your resume is up to date.

Vendor selection and diversification is also key, personally I am not too worried about Amazon or Microsoft’s financial stability at this time. Also where the data is stored is also important to me (With Amazon I get to pick what data centers the data is stored at…)

The “think cloud” assumes that you have a risk management view on remote storage. When you use a 2048 sized encryption key, where it is stored is a low risk proposition.

I do however disagree with thinking that apps are OK to put out there as most security issues around data leakage come from those that have authorized access to the data or the leakage comes via the application layer.

I appreciate your passion and views…

Regards,
Scott
http://www.linkedin.com/in/scottjwright

By: Jason

Jason — Fri, 03 Feb 2012 15:53:46 +0000

Ok Scott W.,

What happens to your data when the “cloud” company either, a., goes under for whatever financial reason, b., gets hacked or DDoS’d because they pissed off the wrong geek, or c., some country’s government makes the service illegal or otherwise inaccessible, or spies on the data?

Sorry folks, data needs to stay local and under YOUR control. We can put apps in the cloud, but our data is far too important to entrust to some company out to make money off hosting it. And don’t give me the, “but no matter where it is it has to be secure and that costs money” argument. Yes, it does cost money to secure YOUR data. It’s part of what makes it important that you do so and ensure it STAYS YOUR DATA! Management needs to understand ALL the risks before putting their data in the hands of others, as should every citizen of every country in the world be wary.

Software as a service via the web, sure, all for it! Putting ALL my data and information about me in someone else’s hands that has NO thought for me other than to make a buck? HELL NO! Things *I* want to share, sure, for a period of time that is necessary I can put data somewhere on the Internet accessible to others. All of it, all the time…NO.

By: Christopher

Christopher — Thu, 05 Jan 2012 11:46:28 +0000

Thanks for the information Kirk, Since I’m not a “tecq” I greatly appreciate the information that you were kind enough to share and the clarity that you helped provide.

By: Scott W

Scott W — Sun, 01 Jan 2012 04:36:30 +0000

O, ya one more thing, Think Cloud folks, most of my current solutions for redundancy do not consider the raid structure when the file are backed up in several locations at the bit level at almost real time for less that the cost of controllers and drives…

Management seems to love no capital cost solutions!

Again just my 2 cents worth,

Scott

By: Scott W

Scott W — Sun, 01 Jan 2012 04:30:53 +0000

Here is what I know. (1 guys 2 cents worth)

Each systems I/O should be well known prior to selecting a storage solution…

Most systems that I need to design require at least 100TB of storage.

Raid 10 is cool where I need performance, often raid 5 is selected due to the price point.

What seems to be missing, in this conversation, is that in the real world the RTO is almost always 24 hours or more and a VM solution is in place so the risk is mitigated by the backup solutions…VmMotion, Log shipping, bit level file replication, and so on, as well as, other real world solutions.

The overall needs are what is important, so pick what works for your management.

Scott

By: Richard Dahlman

Richard Dahlman — Wed, 14 Dec 2011 23:58:37 +0000

I think you are mistaken regarding performance of a 4 disk RAID 10. The performance for a read would indeed be up to 4x. For example, if the array is organized as two 2-disk RAID1′s striped together in RAID0 then all the disks can work simultaneously to retrieve a file. Correct me if I’m wrong. I think you are assuming the speed of RAID1 is only 1x for reads, but either member of the mirrored pair can furnish the data, so this is not true; each drive only has to supply half the requested file.
As regards the general question of RAID 5 versus RAID 10, I agree with the original article. In about 7 years of experience with RAID, I’ve had two RAID 5 failures which were extremely problematic or costly to fix, so I don’t trust it any more. Personally, I’m going with RAID 10 from now on.

By: kschin

kschin — Thu, 13 Oct 2011 00:49:10 +0000

Kirk got that right.

To repeat the point:
“RAID 10 = a striped mirror set”
It is RAID 1+0. The controller makes two RAID-1 (mirror set) sets then make a RAID-0 from that two. Therefore a “1″ followed by a “0″. That also means that a minimum of 4 disks are required for RAID-10.

As a comparison, a minimum of 3 disks are required for RAID-5.

By: Bill

Bill — Fri, 09 Sep 2011 19:04:04 +0000

Hi ccj. I actually appreciated the confirmation that Kirk wrote, but I am a novice as I am just learning about RAID terminology. It was nice to have the clarification.

While I have your attention, can you talk to the following question I have: What do you think about the RAID hardware (or is it software?) that is part of the LAcie2big and the WD MyBook Studio II products? Are using those products as the mirrored sets of a software stripped RAID set a good idea? I have xserves running 10.5 and would like to create a raid 0+1, with the 0 part being managed by the OS and the mirrored part handled by the drive units themselves. Thanks in advance!

By: Xilinx

Xilinx — Fri, 09 Sep 2011 13:24:41 +0000

@John
Regarding sas 600GB 15K new !
€142 & €129
http://tinyurl.com/3dvob6j
http://tinyurl.com/3uxnx7c

By: Kirk M. Schafer

Kirk M. Schafer — Wed, 17 Aug 2011 02:31:42 +0000

@ccj, Nice. These were my original sources: * Why is RAID 1+0 better than RAID 0+1? "[RAID 0+1] is not as robust as RAID 10 and cannot tolerate two simultaneous disk failures.": * http://en.wikipedia.org/wiki/Nested_RAID_levels#Six-drive_RAID_0.2B1 Cheers. Posted by Admin on request.

By: barbara

barbara — Thu, 04 Aug 2011 14:29:18 +0000

I like RAID -10 joking I like RAID 0 + RAID 1 simply far more effective than all of the RAID combined. I personally felt RAID 5 was better but it has to maintain parity which makes its diffcult to maintain.

By: SN

SN — Tue, 26 Jul 2011 02:30:41 +0000

I came here to better understand RAID 10 and this page really explains it well.
Now, I got a bit lost. Is RAID 10 the same as RAID 01? Does a mirrored stripe offer better performance than a striped mirror?? or is it just word play?????
I intend to use 4 X 2TB SATA II disks. I need a total of 4TB with mirrored copy. Which setup do you recommend RAID 01 or RAID 10 ??

thanks

By: ccj

ccj — Mon, 11 Jul 2011 11:07:37 +0000

Why waste everyone else’s time dismantling other people’s correct usage!

We all KNOW that 10 is just a shortcut for saying 1+0/0+1. No one has EVER said that 10 or 50 are implying “better” just because they are a higher number.

This is just in YOUR little head my friend, as we all know that already, so you’re wasting everyone’s time here by adding stupid non-issue points like that. Please go away and annoy the thicko brigade somewhere else.

By: jp

jp — Wed, 06 Jul 2011 11:07:26 +0000

We had an External 10TB enclosure (Enterprise Sata disk) SAS attached in a RAID 5 array. One disk died and while the hot spare was rebuilding (which as you can imagine took ages) we had another die also. Needless to say everything was lost, and a time consuming restore from backup was needed.
It’s now in a RAID 6 config to safeguard against one failure, but after this reading (and other material) I think the RAID 1+0 might have been a better scenario (although reduced storage implications).
Thanks for the article.

By: rtt

rtt — Sun, 03 Jul 2011 19:59:34 +0000

I think some sort of reliable RAID should be used by all people. RAID 5 is not reliable with larger capacity drives since hard drives have become so unreliable, the chances are with a 2+TB array that a rebuild will fail even after a single disk failure. I’ve never liked or trusted RAID 5 in the first place.

If you can’t afford RAID 1+0 then go for RAID 1 at least even though there are no performance gains. RAID 1+0 at least allows for up to 2 drive failures (of course they can’t be part of the same RAID 1).

RAID 1+0 is the future but the main point is that RAID is not a replacement for backups. RAID technologies will always change the implementation with the technology based on the pros and cons. Eg. with SSD RAID 1 will be all we need and performance from 1+0 will not be necessary in my opinion.

By: Chris

Chris — Thu, 30 Jun 2011 18:39:01 +0000

Steve,

I’m new to raids. But are you saying if i have a raid 10 and my motherboard fails i can simply install a new mother board and i’m good to go. Or are you saying i would still have to set up raid in the new motherboard and that it would automatically recognize the existing raid. Very curious about this. please let me know.

thanks for reading

By: Rick

Rick — Thu, 09 Jun 2011 18:55:39 +0000

I used RAID 5 since the mid-90′s and had no problems. I had replaced failed drives and never had an issue until last year when a drive failed and during the rebuild I recieved the unrecoverable read error and that was it. We had to build a new array and restore from tape. That was a not-so-fun weekend.
I now run RAID 10 and 6 only and will probably go away from 6 in the future with the cost of drives going down.

By: Scott

Scott — Sun, 29 May 2011 14:25:39 +0000

I don’t think I’ve ever saw a discussion split hairs as much as this one (and speaking on the internet the abasement of that statement can not be overestimated).

First of all, in a mission critical enterprise environment where cost really isn’t an issue, neither is your RAID array. You will have entire rack redundancy.

Second, RAID 5 is all the redundancy any small scale systems administrator will ever need. Anyone who isn’t budgeting for and routinely replacing drives based on MTBF are, to be blunt, terrible at their job.

Third, the idea that you can safely lose 2 drives in a 1+0 array but not a 5/6 array carries the logical acumen as your average lottery scratch card “system”.

In this day and age we have to assume any discussion of RAID redundancy and cost effectiveness is centered around SO/HO use, which is where RAID 5 shines brightest.

By: Rob

Rob — Tue, 17 May 2011 12:44:16 +0000

What RAID configuration would you recommend for someone who is doing 3d rendering (ala Maya or 3ds Max) and only has 3 drives to work with?

Raid 5? Raid 1 with a backup? Raid 0 with a backup?

I am new to RAID configurations so I appreciate any advice.

By: Kirk M. Schafer

Kirk M. Schafer — Fri, 29 Apr 2011 18:37:01 +0000

While the other reply is very old…if I ran into this…other people still are, too. RAID 5 is not “less than” RAID 10, which incorrectly implies that the higher number is better, instead of demonstrating that it’s a combination RAID set.

In case I’m not being clear, RAID 10 is 1+0, not “ten”. This distinction is important for two reasons: 1) RAID 01 isn’t RAID 1, which is what we’d get pronouncing it as a number, and 2) if we imply that higher is better, RAID 50 should be even better still…when it’s just a different way of doing things. This just isn’t what “5″ vs “10″ vs “50″ means.

For the relevant discussion:
* RAID 01 = a mirrored stripe set
* RAID 10 = a striped mirror set
and…not to distract from the point, the general consensus is that RAID 1+0 is a good choice today.