RAID 5, 6, RAID 0? RAID at all?

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Whitebread

[H]ard|Gawd
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Jan 28, 2002
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I'm pushing the limits of my current storage solution and I so, I'm starting to design a new one. Considering I've amassed over 2 terabytes of data, I'll need a system that can provide sufficient storage (at least 3 Terabytes, preferably more) across 1 single file system.

I'm considering a number of criteria as I begin to plan my next storage solution. Speed, redundancy, failure tolerance and price/performance ratio top the list. Having a continuously accessible backup solution (such as a NAS) should provide all the redundancy and failure tolerance I need, as I should always be able to access the NAS no matter what kind of failures occur computer side. In addition, I will not be booting from this array. This makes me question the efficacy of building a RAID array in my workstation. In effect, all I really need is a JBOD array that spans 2 or 3 2TB disks. But, I'm also looking to maximize transfer and burst speeds, and I'm not confident a JBOD array will be any faster than a single disk itself (no?)

Considering storage speed and array size are my only concerns (as the NAS will serve as a backup drive I can access when/if the workstation array fails), what do you guys think I should do? What array will provide higher read and write speeds while minimizing cost?
 
If you're willing to spend $400 for a true hardware RAID card, RAID 5 would be your best bet for high read/write speeds and redunduncy. However, do note that RAID in and of itself is NOT BACKUP!
 
Danny Bui said:
If you're willing to spend $400 for a true hardware RAID card, RAID 5 would be your best bet for high read/write speeds and redunduncy.
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Hmmm, it will cost that much to get a RAID controller card that it truly hardware RAID? I don't know if the decreased overhead is really worth the increased cost.

Danny Bui said:
However, do note that RAID in and of itself is NOT BACKUP!
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That's why I'll be getting a NAS.
 
Raid 5 with that many drives, chances are he would lose data on a rbuild using 2T drives or higher, that is the problem they say with raid 5, single failure, raid 6 would be better, but even then..
perhaps 2 or 3 seperate raid arrays?

higher read / write will be raid 0 but also highest failure rate, you could do raid 10, but you need alot of drives.

if you got a really food raid card, raid 5 /6 should be decent, and yes a "decent" hardware raid cards would start at $400 for the cheap ones.
 
MrGuvernment said:
Raid 5 with that many drives, chances are he would lose data on a rbuild using 2T drives or higher, that is the problem they say with raid 5, single failure, raid 6 would be better, but even then..
perhaps 2 or 3 seperate raid arrays?

higher read / write will be raid 0 but also highest failure rate, you could do raid 10, but you need alot of drives.

if you got a really food raid card, raid 5 /6 should be decent, and yes a "decent" hardware raid cards would start at $400 for the cheap ones.
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I'm aware of the issues with hard drive failure rates and rebuild errors. Although, I'm not that concerned. If a drive fails in my workstation array, I build a new array (with a good drive) and copy the data from the backup. That will probably take less time than a rebuild. Considering I will be doing daily backups, I'd lose at most 1 days worth of data, and considering how infrequently this data will be altered (I'm talking about music, movies, software and pictures), I don't think I'll be losing anything much at all.
That makes the increased redundancy of RAID 5 and 6 moot, as well as the rebuild issues. That leaves RAID 0. Considering there are no parity calculations, would the increased overhead for software RAID 0 (either via card or a motherboard solution) be noticeable at all?

And what do you mean by 2 or 3 separate arrays? As for RAID 10, I need to limit my drive purchases to 4 maximum, in order to reduce cost. That would not give me enough room to store the data I've got, let alone provide room for expansion without additional purchases.
 
Whitebread said:
And what do you mean by 2 or 3 separate arrays? As for RAID 10, I need to limit my drive purchases to 4 maximum, in order to reduce cost. That would not give me enough room to store the data I've got, let alone provide room for expansion without additional purchases.
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Well, US$450 for four 2TB Hitachi drives. That should be enough for RAID10. I think this solution is cheaper than buying a RAID card to run RAID5. It also has faster write speed And of course much better chance of recovering lost data.
 
Well, I meant that my maximum wold be 4 drives total. Meaning, I can can only purchase 4 storage drives for both my backup server and my workstation at any one time. Although, I just realized that I have about 3TB of usable HDD space on the HDDs I currently have. I think RAID 10 it is.
 
I think you may be a little confused as to what a server ; a nas ; and a backup is.

You are straddling the fence on the speed issue. In you first paragraph you mentioned it needed to be fast.. Then later you mentioned not worrying about losing too much data as their wont be much put over to it. So you want it fast......... so that those 800 mb file transfers dont take as long????? Whats the state of your network ? You running Gig networking or 100 ?? Are you planning on streaming to more than one computer?? How many, and what OS and lan speed are they using?

Also, seriously, nested raid?? Do you really need that?

I would bet a Freenas box running raid 0 would probably be sufficient. And a lot cheaper too. Maybe then you could implement an actual backup other than raid ???
 
jay2472000 said:
I think you may be a little confused as to what a server ; a nas ; and a backup is.

You are straddling the fence on the speed issue. In you first paragraph you mentioned it needed to be fast.. Then later you mentioned not worrying about losing too much data as their wont be much put over to it. So you want it fast......... so that those 800 mb file transfers dont take as long????? Whats the state of your network ? You running Gig networking or 100 ?? Are you planning on streaming to more than one computer?? How many, and what OS and lan speed are they using?

Also, seriously, nested raid?? Do you really need that?

I would bet a Freenas box running raid 0 would probably be sufficient. And a lot cheaper too. Maybe then you could implement an actual backup other than raid ???
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I am using NAS loosely. This is how I envision my home network.
The "NAS" will store a separate copy of my sensitive data, data which is generated at my workstation. This could include, but is not limited to, movies, music, pictures, personal documents, etc. A third computer will serve as the HTPC. I'll also have internet radio(s) in other locations around the house where I wish to access my own music collection, as well as internet radio broadcasts (bedroom, basement, etc). The HTPC and the internet radio(s) will stream data from the NAS, and the NAS will be updated regularly via backups from my workstation PC. Effectively, the NAS (server, whatever) will store a copy of the data I wish to share with other people/computers so that my workstation is not continuously accessed, and keep a separate copy to protect against failures.

Most of this data is static, other than my personal documents that is. Therefore, once the initial transfer has been completed, I don't ever see any situation where many tens or hundreds of gigabytes will need to be transferred (unless, of course, a failure occurs or I just happen to add a huge quantity of music or movies to my collection at one time). And since I will not be accessing the data stored on the NAS from my workstation, data flow will mostly be one way(workstation -> NAS -> (HTPC, Internet Radios, Wireless devices, etc)). This is why I don't particularly desire a high speed network attached storage solution, so long as the system is quick enough to stream 1080p movies to other PC's that need it. The network will be gigabit and there will be a mix of Windows 7 and linux PCs (Ive been playing with linux on my laptop).

I intended upon using my old desktop, with the 5 HDDs I have laying around (2x1TB, 1x500GB, 1x400GB, 1x250GB), downloading some linux based NAS solution (like freenas) and building the backup/streaming server with a JBOD array that I've been talking about. Buying a commercial solution would have just been wasteful.

I will not ever need to have continuous access to the data I'm going to be placing upon this server. I can find other things to do if I cannot watch a movie or access my music, I won't be losing any money if I've got a bit of downtime. Having 2 separate copies across 2 different boxes in different parts of the house, in my mind, reduces the chances of losing my data, as I doubt I'd ever lose both file systems simultaneously. If I did, It would likely be due to some far more serious issue and the data loss would be of little immediate worry. This is why I've said that I don't really need to maximize up time with a RAID level that does processor intensive parity calculations. But since I'll be purchasing 3 or more drives, I'm looking into the possibility of maximizing both storage and speed (as well as maintaining one continuous filesystem) on my workstation rig (but not on the server itself). I was likely a bit hasty when I affirmed the recommendation to go with RAID 10, particularly because it is not space efficient. Considering the fact that I'm not too concerned with the increase in failure probability, I might just go with RAID 0, but I'm not sure, yet.

*I do realize that having the "backup" double as a media server probably isn't good form. But, I don't think I'd really seriously increase the chances of failure, since we are dealing with a maximum of ~10 drives and a minimum of 2 filesystems between my workstation and the server.

What do you think?
 
Whitebread said:
I am using NAS loosely. This is how I envision my home network.
The "NAS" will store a separate copy of my sensitive data, data which is generated at my workstation. This could include, but is not limited to, movies, music, pictures, personal documents, etc. A third computer will serve as the HTPC. I'll also have internet radio(s) in other locations around the house where I wish to access my own music collection, as well as internet radio broadcasts (bedroom, basement, etc). The HTPC and the internet radio(s) will stream data from the NAS, and the NAS will be updated regularly via backups from my workstation PC. Effectively, the NAS (server, whatever) will store a copy of the data I wish to share with other people/computers so that my workstation is not continuously accessed, and keep a separate copy to protect against failures.

*I do realize that having the "backup" double as a media server probably isn't good form. But, I don't think I'd really seriously increase the chances of failure, since we are dealing with a maximum of ~10 drives and a minimum of 2 filesystems between my workstation and the server.

What do you think?
Click to expand...
I have a fairly similar setup actually: My WHS server has a copy of data that I want to share with other PCs. I still have a copy of that data on my desktop just in case. WHS streams content to my 360. In addition, I've turned on duplication for critically important data that I never want to lose. Example: I have every single picture I've ever taken stored on my desktop. I also have a copy of those pictures on my server. The folder that that holds those pics have duplication turned on just in case the WHS server dies. In addition, I also have a copy of those pictures stored on external hard drives. Works fairly fine for me.

Whitebread said:
I intended upon using my old desktop, with the 5 HDDs I have laying around (2x1TB, 1x500GB, 1x400GB, 1x250GB), downloading some linux based NAS solution (like freenas) and building the backup/streaming server with a JBOD array that I've been talking about. Buying a commercial solution would have just been wasteful.
Click to expand...
Just a couple of nitpicks: What PSU does your old desktop have? Also, FreeNAS is BSD based, not Linux based.

A Linux JBOD setup isn't too bad. Tried it myself before I switched to WHS.
 
Danny Bui said:
I have a fairly similar setup actually: My WHS server has a copy of data that I want to share with other PCs. I still have a copy of that data on my desktop just in case. WHS streams content to my 360. In addition, I've turned on duplication for critically important data that I never want to lose. Example: I have every single picture I've ever taken stored on my desktop. I also have a copy of those pictures on my server. The folder that that holds those pics have duplication turned on just in case the WHS server dies. In addition, I also have a copy of those pictures stored on external hard drives. Works fairly fine for me.


Just a couple of nitpicks: What PSU does your old desktop have? Also, FreeNAS is BSD based, not Linux based.

A Linux JBOD setup isn't too bad. Tried it myself before I switched to WHS.
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Glad to hear that it works. And thanks for the correction about freenas. Is there a folder duplication like option with such an OS?

And I have a 480 watt Xclio PSU in that "old desktop". That old thing is actually what I'm typing on now. I call it old because, well, it is old. Four years old. I will be replacing it once I graduate, which will be in about a week and a half. Those 5 drives are already installed in the computer and storing just a touch over 2 TB of data. I don't have any instability issues, except for when I push the CPU to hard as it gets quite warm in my room during hot summer days.
 
AFAIK, only WHS has folder duplication.

I would recommend a new PSU just to be on the safe side. For a modest system, I recommend the following:
$40 - Antec Earthwatts Green EA380D 380W PSU
$50 - Corsair 400CX 400W PSU
 
Other then the Burst speed I would say a WHS sounds like the ticket. I Run it simply because of its disk management. I Currently have 4tb of storage between 3 Samsung eco drives & have plans to add leastwise 2 more whenever I catch them on a good sale or I fill up what I have. WHS's file system is what most people want when they start looking at ZFS. Something that will grow with your needs & be flexible so you don't have to buy allot of special hardware or even matched drives. Plus it will run on an atom so if your building from scratch you can make them pretty light on the power bill..
 
White, sounds like you got a good plan. I didnt realize that you were planning on having 2 NAS. In that case, I would say youre pretty well covered. I have 2 WHS boxes and a Freenas. The WHS is nice because it is a familiar OS, expansion is really easy, it does bare metal recoveries, etc. One WHS acts as a server, the other just backs it up. The Freenas system is just some old IDE drives I JBOD'ed together and is running on a Cyrix 333 Mhz processor with 256 Mb ram. Its about the only useful thing I could thing of to do with that old hardware. I use it for commonly accessed files. Music, pictures, etc. It stays on quite a bit and I love it, the transfers arent fast ( 5Mb/s) but hey, for the money it was fun. Im willing to bet if you found a compatible sata card or a mobo with on board youll be happy with the transfers and speed of Freenas. And hey, if you dont like it, you can always spend money on an OS later, rather than before.
 
Danny Bui said:
AFAIK, only WHS has folder duplication.

I would recommend a new PSU just to be on the safe side. For a modest system, I recommend the following:
$40 - Antec Earthwatts Green EA380D 380W PSU
$50 - Corsair 400CX 400W PSU
Click to expand...

They're cheap, I'll go for the Corsiar model.
 
bastage said:
Other then the Burst speed I would say a WHS sounds like the ticket. I Run it simply because of its disk management. I Currently have 4tb of storage between 3 Samsung eco drives & have plans to add leastwise 2 more whenever I catch them on a good sale or I fill up what I have. WHS's file system is what most people want when they start looking at ZFS. Something that will grow with your needs & be flexible so you don't have to buy allot of special hardware or even matched drives. Plus it will run on an atom so if your building from scratch you can make them pretty light on the power bill..
Click to expand...

It sounds like a good solution, but it is not free. Freenas is. Would there be a filesystem limitation with 32bit WHS? From what I gather, that's more a hardware issue, but I just want to make sure.
 
jay2472000 said:
White, sounds like you got a good plan. I didnt realize that you were planning on having 2 NAS. In that case, I would say youre pretty well covered. I have 2 WHS boxes and a Freenas. The WHS is nice because it is a familiar OS, expansion is really easy, it does bare metal recoveries, etc. One WHS acts as a server, the other just backs it up. The Freenas system is just some old IDE drives I JBOD'ed together and is running on a Cyrix 333 Mhz processor with 256 Mb ram. Its about the only useful thing I could thing of to do with that old hardware. I use it for commonly accessed files. Music, pictures, etc. It stays on quite a bit and I love it, the transfers arent fast ( 5Mb/s) but hey, for the money it was fun. Im willing to bet if you found a compatible sata card or a mobo with on board youll be happy with the transfers and speed of Freenas. And hey, if you dont like it, you can always spend money on an OS later, rather than before.
Click to expand...

Yep, I'll have a similar system, expect the "junk box" will be an overclocked opteron with 2 gigs of ram. :D
 
Whitebread said:
It sounds like a good solution, but it is not free. Freenas is. Would there be a filesystem limitation with 32bit WHS? From what I gather, that's more a hardware issue, but I just want to make sure.
Click to expand...

There is not filesystem limitation per se with 32bit WHS. I've seen plenty of people have 10TB WHS setups and no real isse there.
 
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