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RAID 5 vs. RAID 10. Your thoughts.

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Tangier Clarke
RAID 5 vs. RAID 10. Your thoughts.
on Oct 18, 2015 at 4:46:52 pm

Folks, I 've been using RAID 10 for editorial with a Rocstor ArcticRoc Hybrid 7T. I've been very happy with their products. I see so many raids on sale setup for RAID 5. I am too paranoid to consider RAID 0 because things are bound to fail eventually. I don't favor software RAID configs. To the extent that I can be I am pretty religious about buying Hitachi drives only, then Western Digital. Most recently I bought this enclosure (http://eshop.macsales.com/item/MISC/0G033S2TB0GB/) because it was the only product I could find at the time of this writing that had everything I wanted in this form factor; until Rocstor releases their new desktop products this year and I'm heading to the LaCie rack series soon possibly too.


I referenced this (http://www.miracleas.com/BAARF/RAID5_versus_RAID10.txt) article a long time ago. I'd love to know your thoughts folks.

Tangier


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Bob Zelin
Re: RAID 5 vs. RAID 10. Your thoughts.
on Oct 18, 2015 at 5:33:10 pm

keep it raid 5. If you are brave in the future and starting all over, make it raid 6 so you can have 2 drive failures, instead of 1.
I hate mirroring.

Bob Zelin

Bob Zelin
Rescue 1, Inc.
bobzelin@icloud.com


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Jon Schilling
Re: RAID 5 vs. RAID 10. Your thoughts.
on Oct 20, 2015 at 3:28:45 am

Bob Z is right, there's no advantage to RAID 10 over 5, in fact
RAID 5 is a better choice for a number of reasons.
RAID 10 will be slower than RAID 5
RAID 10 reduces your usable capacity of your drives,
It will also slow your performance.

Jon Schilling
Sales and Marketing

23890 Copper Hill Drive -Suite 103
Valencia, CA 91355 - USA
e-Mail: Jon@GBLabs.com
Mobile: +1 661-495-8641
Skype: cgijon
http://www.gblabs.com


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Tangier Clarke
Re: RAID 5 vs. RAID 10. Your thoughts.
on Oct 20, 2015 at 3:30:43 am

Both of you feel that way even after reading the article at this link below?:

http://www.miracleas.com/BAARF/RAID5_versus_RAID10.txt

Tangier


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Jon Schilling
Re: RAID 5 vs. RAID 10. Your thoughts.
on Oct 20, 2015 at 3:36:32 am

My thoughts are unchanged & I've been dealing
With this question for years. You are playing with fire when you throw software RAID 0 on top of RAID 1 (giving you RAID 10). Of course you're free to do as you wish but you asked
For opinions of Pros ;)

Jon Schilling
Sales and Marketing

23890 Copper Hill Drive -Suite 103
Valencia, CA 91355 - USA
e-Mail: Jon@GBLabs.com
Mobile: +1 661-495-8641
Skype: cgijon
http://www.gblabs.com


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Tangier Clarke
Re: RAID 5 vs. RAID 10. Your thoughts.
on Oct 20, 2015 at 3:38:40 am

Understood. I don't use software raids though. RAID 10 in hardware.

Tangier


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Jon Schilling
Re: RAID 5 vs. RAID 10. Your thoughts.
on Oct 20, 2015 at 3:41:24 am

Stick with the RAID 5 & if you want more security, RAID 6.
Like Master Zelin said.

Good luck!

Jon Schilling
Sales and Marketing

GB Labs
23890 Copper Hill Drive -Suite 103
Valencia, CA 91355 - USA
e-Mail: Jon@GBLabs.com
Mobile: +1 661-495-8641
Skype: cgijon
http://www.gblabs.com


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Bob Zelin
Re: RAID 5 vs. RAID 10. Your thoughts.
on Oct 20, 2015 at 3:51:40 pm

remember - both AVID and Facilis (early shared storage people in OUR industry) did RAID 1. Now, neither company uses mirroring. Why would you sacrifice half your storage for a mirror ?

There are many opinions in the electronics industry. The only opinion that matters to me, is the collective opinion that is used by manufacturers that participate in the VIDEO industry - companies that you see advertise here on Creative Cow, companies that participate at NAB, CCW, SMPTE, SBE, etc. No other computer or IT expert opinion matters to me (even if they are "right").

Bob Zelin

Bob Zelin
Rescue 1, Inc.
bobzelin@icloud.com


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Tim Wilson
Re: RAID 5 vs. RAID 10. Your thoughts.
on Oct 20, 2015 at 5:39:49 pm

[Bob Zelin] "The only opinion that matters to me, is the collective opinion that is used by manufacturers that participate in the VIDEO industry"

This is so, so, so important. The needs of video storage are completely different than typical storage needs in business, medical research, finance, and all the other fields that rely on massive arrays.

As one example, enterprise storage on the scale we work with is still being used to store lots of small files, largely being accessed randomly, with not much relation to each other. They can be pulled up in pretty much any order, as fast as possible, and nobody will be left wondering where the hell their file is.

Video and film production is almost exactly the opposite. Dramatically fewer files, dramatically larger files, and they MUST be delivered in a specific sequence, at regularly spaced, uniform intervals.

Storage designed for these environments are not even trying to do the same the thing, so treat them as if they are will always yield bad results.

Making things even more complicated is the need for large amounts of metadata to also stay attached to camera and render files, which is why large VIDEO storage will often include a separate metadata server. There's a lot of overhead to making sure the right files are being pulled up in the right order, at the right time.

We RELY on that overhead. The enterprise needs that overhead GONE.

Balancing the needs of feeding DATA and feeding METADATA is a specialized task. Most vendors don't need to do this, so they don't.

That's why some of the biggest companies in the STORAGE business do not advertise here. Their offerings simply aren't suitable for our business.

This is also why Avid is not trying to sell ISIS storage to Visa or Amazon. It's massively redundant, reliable, fast, scalable -- but entirely optimized for fewer, larger files.

This is also why some IT guys look at the advertisers in Creative COW, say "Who the hell is Facilis?" and insist that you use EMC or something. Storage companies that IT guys know. GOOD storage, even GREAT storage.

But the WRONG storage, because it doesn't even attempt the most basic, core task that Facilis, MAXX Digital, and all of these other fine companies build into their foundations.

Bob can usually take care of his own rants, and while my temperature may be turned down a degree, I want to underscore that this is a case where his rant may be understated a degree too. :-) This is, as Frank Zappa used to say, the crux of the biscuit.


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Jack Battiste
Re: RAID 5 vs. RAID 10. Your thoughts.
on Nov 25, 2015 at 11:56:50 pm
Last Edited By Jack Battiste on Nov 26, 2015 at 12:53:55 am

Hi Tangier, First time caller, long time listener.

1. I don’t buy into the mindset that one type of RAID level is better than the other, because the “best” way to configure a RAID array, always depends upon specific needs. More importantly, I have noticed that folks tend to fall into two camps, those that are picturing worst case scenarios, and those who are looking to squeeze out the very last drop of performance, or capacity, or available budget. Thus both creative professionals and IT staff alike are confronted with two uncomfortable options, more money now or a new resume later.

2. Somebody who is looking to handle a worst case scenario, and evaluating risk management will likely favor mirrored arrays over parity arrays. Parity fans are quick to offer up Raid 6 as a quick counter punch, but let’s examine that more closely. RAID-6 offers insurance on a 2 drive failure, while Raid 10 offers up to 50% drive failures. With 4 drives this not significant. As the number of drives increases though, the differences here become quickly apparent. A 12 drive RAID-6 offers insurance for a maximum of two drive failures, while keeping the volume of 10 drives. A 12 spindle RAID-10 will offer insurance on a maximum of 6 dead drives, but is doing so by taking a 50% hit on capacity. Vocal advocates for RAID-6 will be looking at the 50% capacity hit and will recoil in horror. Might even point out that having “six spare tires” only works as long as you get flats on the right six. Meanwhile the President and CEO of the RAID-10 Fan Club is quite happy to Mad Maxing it with 6 spare tires, and will point to the mathematical probabilities of unrecoverable read errors when rebuilding parity arrays with when the drives are 3TB or larger.

3. For RAID 5 & 6, a reasonable approach is favor enterprise grade drives with URE (unrecoverable read error) rates of 1 read error for every 10^15, or 10^16. RAID-10 is more forgiving when using lower end drives because URE's do not effect RAID-10 during a rebuild, you just end up with a bad block, not a destroyed array. For this reason, cheaper drives will often be used to offset the cost impact of the lower space utilization. Matt Simmons has summarized this point quite succinctly :

Quote : “ We started off with no one knowing what RAID was, then we went to everyone knowing what RAID was (or at least, being familiar enough with it to mistake it for being a backup). RAID-5 was sweet, because it had a parity stripe, and if you had a bunch of drives shoved together, it could tolerate the loss of a drive. How awesome was that? Then Robin Harris went and wrote Why RAID-5 Stops Working in 2009. It was an excellent article, and it was exactly right for the purposes that Robin meant it. It’s been a good way to point out to people that maybe they shouldn’t have RAID-5 configurations with 40TB worth of the cheapest SATA drives known to man. (continued)

RAID-5 has a parity, so that any individual pieces of data can be lost, and instead of recovering the data by copying it, it’s recalculated by examining the remaining data bits. So when we encounter a URE during normal RAID operations, the array calculates what the missing data was, the data is re-written so we’ll have it next time, and the array carries on business as usual. But when a drive dies, we have to replace it, and that’s when things get hairy. In order to rebuild the array, the new drive needs to be populated, and in order to do that, the entire contents of the remaining drives need to be read, in order to calculate the parity information. Assuming we have a RAID-5 array that has 3 3-TB disks, we’re now reading 6 terabytes of information. What is the statistical likelihood of encountering a URE? 1 in 2. A coin-flip. Have a RAID-5 array with 4 3-TB disks? That’s 1 in 1, almost certainly a failure. You can see how quickly this goes downhill. Now, a lot of people see this, freak out, and say “oh my god, I’m never using RAID-5 again! RAID-5 is the devil! It’s EVIL!”, but remember what is driving the numbers…it’s the URE rate."

—Matt Simmons, I come not to Praise RAID-5 … But Not To Bury It Either
http://www.standalone-sysadmin.com/blog/2012/08/i-come-not-to-praise-raid-5...

Hope this is useful!

Jack Battiste



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Tangier Clarke
Re: RAID 5 vs. RAID 10. Your thoughts.
on Nov 26, 2015 at 12:09:23 am

Thanks for this fantastic insight. Much appreciated. I stayed with RAID 10 despite the postings about what the industry does. There are so many factors as you put it and different circumstances governing this decision; so very true. This is not to say I would stay with RAID 10 in all scenarios, but with the storage I am working with for the size of the projects, the post needs, and the budget of course, it's the best overall situation pre and post potential drive failure.

Tangier


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Jack Battiste
Re: RAID 5 vs. RAID 10. Your thoughts.
on Nov 26, 2015 at 12:32:30 am
Last Edited By Jack Battiste on Nov 26, 2015 at 12:40:02 am

^^ Sounds good. I actually use both RAID-5 and RAID-10. My workstation houses A four drive RAID-10 internally which store my current projects. In the event of a drive failure I want the quickest re-build possible with minimal deadline busting downtime. I have two 4 drive RAID-5 arrays for hourly back ups (OWC QX2 connected via PCIe SSD port). One BackUp is always running, the other I update once per week and store off-studio as theft and fire insurance. So that's three copies of everything. Perhaps a bit over the top by many standards but works for me!

Jack Battiste
http://www.BattisteCreative.com
Retouching, Illustration & CGI


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Tangier Clarke
Re: RAID 5 vs. RAID 10. Your thoughts.
on Nov 26, 2015 at 12:34:46 am

Yeah, that's what I am doing as well - Raid 10 on a 4-drive system for my current projects and I have it that way for the same reasons as you.

Tangier


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Russ D'Arensbourg
Re: RAID 5 vs. RAID 10. Your thoughts.
on May 16, 2016 at 4:44:18 pm

[Tangier Clarke] "
Both of you feel that way even after reading the article at this link below?:

http://www.miracleas.com/BAARF/RAID5_versus_RAID10.txt"


That appears to be an article from 'Battle Against Any Raid Five' folks. Hardly impartial. I notice a couple interesting things here.
More than one reference to databases and such. No mention of heavy media storage usage.
Also the linked article, and several others linked from their homepage return 404 errors. Maybe they lost their storage?

At my old job at NBC we lost a raid 5 array while I was on vaction. After recovering the data from backup (remotely) we specced another larger raid 5 array. With a robotic tape backup.


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