Does anyone use RAID anyomore for HTPC - AVS Forum
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post #1 of 21 Old 11-14-2014, 02:33 PM - Thread Starter
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Does anyone use RAID anyomore for HTPC

It would seem most now use a SSD as a boot and then regular drives for data which seems to negate the need for RAID. While I value my movie collection I don't see a reason to use RAID to do a simultaneous backup so again no need for RAID. Am I missing something. I am about to build a HTPC / couch gaming system and was wondering if anyone could think of a reason why I might use RAID.
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post #2 of 21 Old 11-14-2014, 02:43 PM
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Well if your collection is ripped from your physical media, you already have a backup. The only other benefit of a RAID here is bandwidth. But as we are playing highly compressed media at home, we don't need the performance of a stripped RAID.

So to answer your question - you don't need a RAID in most common HTPC setups with average library sizes.

But for a large collection, if you have to go out and find the drive that has the movie you want, and say you have 10 or 20 drives on a shelf, then you are not that far removed from just playing the DVD or Bluray directly. A RAID gives you access to all your content more or less on the fly depending on how you set up drive power management. For large libraries a RAID still makes sense.

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post #3 of 21 Old 11-14-2014, 04:19 PM
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I using RAID5 to protect me from having to re-rip all my DVDs and BDs in the event of a drive failure. I've already had (multiple) drives fail over the years and then all I needed to do is just replace the failed drive and all my data is rebuild/restored. I also use a SSD for the OS and media center software. My RAID is just for data storage.
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post #4 of 21 Old 11-14-2014, 08:00 PM
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Disks fail - it's a question of when, not if. The additional questions are how much data is lost and how difficult it is to recover. Raid solutions help minimize data loss and speed recovery time when the inevitable happens. Most media server implementations are better served with software raid or a commercial NAS rather than PC based hardware raid, though.

Raid isn't a backup, however - it's important to use it for its intended purpose.
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post #5 of 21 Old 11-15-2014, 05:57 AM
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Most of today's software RAID solutions have at least one parity drive so your data is protected to a certain extent, but usually only if just one drive dies in the parity configuration. Still, it does present you with a minimal level of confidence that you don't have to restore all the data since you can usually just plug in a new drive and let it rebuild it for you. Media servers don't require the same backup requirements as data servers since most of us still have the physical media as backups.
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post #6 of 21 Old 11-15-2014, 08:46 AM
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Am guessing these days RAID is relatively cheap and easy for no-thinking backup, but yeah, if you know exactly what you need, you maybe not want to do RAID.
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post #7 of 21 Old 11-15-2014, 09:07 AM
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Raid 10 for Virtual Machine Storage, the more disk in the pool the faster the pool which is nice.

Flexraid for Movie Storage
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post #8 of 21 Old 11-15-2014, 09:35 AM
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Today, I can't imagine NOT using some form of RAID for home theater server duties. Life is too short to have a drive "die" and then figure out exactly what data was lost on that particular drive and re-rip just that stuff or even recover from backups (a major-major pain).

I think it really just comes down to the combination of two things:

1. How much data (movies, music, pictures, computer image backups, programs, etc) do you need to store today and for the foreseeable future ?

2. What are the largest affordable drives that are currently manufactured?

If you only need two or three "drives" worth for storage for now and in immediate future, then maybe forget RAID and do backups.

The minute that you need more than two-three drive's worth, I would look at at least one parity drive up to four drives, and two parity drives up to sixteen drives.

At the rate that manufacturers are increasing storage density (bigger drives), and, the rate that my appetite for data has both stopped growing and is even diminishing, I can foresee a day where I ditch a RAID-like system.

p.s. standard disclaimer: even with RAID, make backups of irreplaceable data like pictures and documents!
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post #9 of 21 Old 11-15-2014, 05:26 PM
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I use RAID 6 with my server. I also virtualize everything with XenServer and GPU passthrough to Media VM and RAID card to Windows Server VM for storage and backup.
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post #10 of 21 Old 11-16-2014, 07:51 AM
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Quote:
Originally Posted by yevgeny View Post
I use RAID 6 with my server. I also virtualize everything with XenServer and GPU passthrough to Media VM and RAID card to Windows Server VM for storage and backup.
I tried Xen but WHS would not load and i had a bunch of other issues overall, any reason you use raid 6 over 10???
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post #11 of 21 Old 11-16-2014, 01:44 PM
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Quote:
Originally Posted by davidtt485 View Post
I tried Xen but WHS would not load and i had a bunch of other issues overall, any reason you use raid 6 over 10???

I used Citrix XenServer not Xen. While both are free first, was much easier for me to set-up.


RAID6 because it offers more protection and space than RAID10.
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post #12 of 21 Old 11-16-2014, 01:56 PM
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Copied from LSI/3Ware User guide.


RAID 10
RAID 10 is a combination of striped and mirrored arrays for fault tolerance
and high performance.
When drives are configured as a striped mirrored array, the disks are
configured using both RAID 0 and RAID 1 techniques, thus the name RAID
10 (see Figure 6). A minimum of four drives are required to use this
technique. The first two drives are mirrored as a fault tolerant array using
RAID 1. The third and fourth drives are mirrored as a second fault tolerant
array using RAID 1. The two mirrored arrays are then grouped as a striped
RAID 0 array using a two tier structure. Higher data transfer rates are
achieved by leveraging TwinStor and striping the arrays.
In addition, RAID 10 arrays offer a higher degree of fault tolerance than
RAID 1 and RAID 5, since the array can sustain multiple drive failures
without data loss. For example, in a twelve-drive RAID 10 array, up to six
drives can fail (half of each mirrored pair) and the array will continue to
function. Please note that if both halves of a mirrored pair in the RAID 10
array fail, then all of the data will be lost.
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post #13 of 21 Old 11-16-2014, 02:58 PM
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Quote:
Originally Posted by yevgeny View Post
I used Citrix XenServer not Xen. While both are free first, was much easier for me to set-up.


RAID6 because it offers more protection and space than RAID10.
RAID6 does not give more protection than RAID10. RAID10 provides full redundancy, while RAID6 only gives you a redundant parity drive.
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post #14 of 21 Old 11-16-2014, 03:56 PM
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Quote:
Originally Posted by dfkimbro View Post
RAID6 does not give more protection than RAID10. RAID10 provides full redundancy, while RAID6 only gives you a redundant parity drive.

Raid 6 will endure the loss off 2 drives failures anywhere across the setup whereas with Raid 10 it greatly depends on where that second failure occurs.
Granting that RAID 10 may survive even with more than 2 drive failures, they would have to be specific ones. If the wrong two drives fail you will end up with a total loss of data


Raid 0 : loose 1 drive = dead
Raid 10 : loose 1 drive = degraded : loose another drive = depends ( 2nd drive : if from the fail set = degraded : if from working set = dead)
Raid 5 : loose 1 drive = degraded : loose another one = dead
Raid 6 : loose 1 drive = degraded : loose another drive = degraded : loose 3rd = dead


You turn
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post #15 of 21 Old 11-16-2014, 04:50 PM
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Quote:
Originally Posted by yevgeny View Post
Raid 6 will endure the loss off 2 drives failures anywhere across the setup whereas with Raid 10 it greatly depends on where that second failure occurs.
Granting that RAID 10 may survive even with more than 2 drive failures, they would have to be specific ones. If the wrong two drives fail you will end up with a total loss of data


Raid 0 : loose 1 drive = dead
Raid 10 : loose 1 drive = degraded : loose another drive = depends ( 2nd drive : if from the fail set = degraded : if from working set = dead)
Raid 5 : loose 1 drive = degraded : loose another one = dead
Raid 6 : loose 1 drive = degraded : loose another drive = degraded : loose 3rd = dead


You turn
You can lose every disk in a set of a RAID10 array and the data will still be available. For example, in a 12-disk RAID10 array, you could lose every other odd-numbered disk in one set (i.e., disks A1, A3, A5) and every other even disk in the other set (i.e., disks B2, B4, B6) and the array will not be lost. As long as you don't lose a matched pair (like losing both A1 and B1) then the RAID10 array will survive.

Additionally, RAID6 writes are slower than RAID10.

RAID6 is certainly cheaper for the same amount of useable storage, and it's "ok" if you need more space and are willing to take a hit on the resilience of the array and the write speed.

Here is a good place to start reading what data storage experts say...http://community.spiceworks.com/topi...d-6-or-raid-10

More from Scott Alan Miller, the data storage guru...http://community.spiceworks.com/topi...server-storage

And http://www.smbitjournal.com/2012/11/...rives-in-2013/

And this for I/O performance (note the speed increase from RAID6 to RAID10 regardless of the card or the application) http://www.tomshardware.com/reviews/...r,3028-12.html

Last edited by dfkimbro; 11-16-2014 at 06:13 PM.
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post #16 of 21 Old 11-16-2014, 05:05 PM
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Quote:
Originally Posted by dfkimbro View Post
That's not how it works. You can lose every disk in a set of a RAID10 array and still swapover to the other set with no data loss, regardless of how many disks are in the array.
Swapover? There's is no swapping over in RAID10. All the drives are online all the time. And if you lose every disk, your array is toast.

Quote:
Originally Posted by dfkimbro View Post
With RAID 6, you can only lose a max of 2 disks (any combination of parity and data disks) without an unrecoverable array.
RAID6 doesn't have parity and data disks. RAID6 (and RAID5) utilize distributed parity. All drives contain data and parity.

Quote:
Originally Posted by dfkimbro View Post
In a 12-disk RAID10 array, you could lose every other odd-numbered disk in one set (i.e., disks A1, A3, A5) and every other even disk in the other set (i.e., disks B2, B4, B6) and the array will not be lost. As long as you don't lose a matched pair (like losing both A1 and B1) then the RAID10 array will survive.
That is correct. But RAID10 cannot survive the loss of any matched pair, which means it can't (always) survive the loss of two drives. RAID6 can always survive the loss of two drives.

Since there is no clear cut number of failed drives that RAID10 can survive (it could fail after 2, it could survive after 50, it just depends on which drives fail) you guys can go in circles all day long over this. It's just going to depend on the particular circumstance. However, I would argue that since RAID6 can protect against the failure of any two drives, and RAID10 can't that in that regard RAID6 does offer more redundancy.

RAID protection is only for failed drives. That's it. It's no replacement for a proper backup.
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post #17 of 21 Old 11-16-2014, 06:15 PM
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Quote:
Originally Posted by ajhieb View Post
Swapover? There's is no swapping over in RAID10. All the drives are online all the time. And if you lose every disk, your array is toast.

RAID6 doesn't have parity and data disks. RAID6 (and RAID5) utilize distributed parity. All drives contain data and parity.

That is correct. But RAID10 cannot survive the loss of any matched pair, which means it can't (always) survive the loss of two drives. RAID6 can always survive the loss of two drives.

Since there is no clear cut number of failed drives that RAID10 can survive (it could fail after 2, it could survive after 50, it just depends on which drives fail) you guys can go in circles all day long over this. It's just going to depend on the particular circumstance. However, I would argue that since RAID6 can protect against the failure of any two drives, and RAID10 can't that in that regard RAID6 does offer more redundancy.
Thank you for the corrections and clarifications. I shouldn't have used the term swapover. I meant that an entire set can fail and the other set will still be available.

I wasn't thinking of distributed parity, but of separate parity disks. Point taken.

I corrected my previous post to be more accurate.
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post #18 of 21 Old 11-17-2014, 03:43 AM
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didn't mean to start any trouble, i did a lot of research and i couldn't find anyone who was using raid 6 and i liked the idea of having more usable space. I went with 10 though for the performance aspect. I use a cheapy dell controller literally was like 30 bucks and raid 10 and the performance for the virtual machines is excellent.

I did try Xenserver as well but there was something wrong with the template for Windows Home Server, it just would not load no matter what settings i picked.
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post #19 of 21 Old 11-19-2014, 10:11 AM
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I just run the risk with RAID5 for now in my old PowerEdge. I've had two drive failures in the past year. I just immediately shut the server down, gone down to Best Buy and bought a replacement 2 TB drive to replace the one that failed, re-built, and kept moving along. I have done this for the past 7 yrs. or so with my "server" setup (whatever machine happened to be my storage server at various points during that time up till now). I am looking forward to the falling prices of 5 and 6 TB drives so I can simply buy two of those and backup my RAID5 (six 2 TB drives) to a couple of externals. Right now I only backup my apps and music to a 750 GB (that's almost full) external drive I had laying around. I debate with myself all the time about which route I should go moving forward. Server to a NAS instead (with larger drives)? Server works fine, so keep it and replace the drives with larger internal 5 TB or 6 TB drives once they get to where I consider to be "cheap"? Given that I have reached the point where seasons of TV shows I'll never watch again end often enough for me to keep enough free space on my server for more\different media, I have just become complacent.
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post #20 of 21 Old 11-19-2014, 10:29 AM
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Quote:
Originally Posted by ajhieb View Post
However, I would argue that since RAID6 can protect against the failure of any two drives, and RAID10 can't that in that regard RAID6 does offer more redundancy.
Yeah, but how fast can you make a snapshot backup of a RAID6 array? With RAID10, I do it in about 300ms.
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post #21 of 21 Old Yesterday, 07:42 PM
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Yeah, but how fast can you make a snapshot backup of a RAID6 array? With RAID10, I do it in about 300ms.
I guess you missed the topic of this thread. We are talking about HTPC at home not Biz environment at work.
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