RAID 5 VS RAID 10 for home NAS

pwjohnston

So you (or I as it were) are building a home NAS. You have a case that holds 4 SATA drives, any size. Focusing on data preservation/recovery over performance/size which would you pick and why? (It might also be helpful to note that I’m attempting this with openfiler linux so I’ll either be formatting the disks with ext3 or XFS.)

blargoe

I'd go with Raid 5 for the added capacity myself unless the activity is going to be write intensive

kalebksp

If you're goal is redundancy with no concern for speed or space I would go with RAID 6.

kalebksp

I forgot the why part.

RAID 6 is like RAID 5 but gives you double parity, meaning that two drives would have to fail before you'd lose data.

blargoe

Not with just 4 drives. Well, you can, but you'd get the same usable space in raid 10 since you're losing 2 usable disks either way and 10 would perform better than 6 for writes.

kalebksp

blargoe wrote: »

Not with just 4 drives. Well, you can, but you'd get the same usable space in raid 10 since you're losing 2 usable disks either way and 10 would perform better than 6 for writes.

True, but you wouldn't have the same level of redundancy. If you lost the first disk in each set of RAID 0 you'd lose data. Even though that's pretty unlikely, it's technically less redundant.

jibbajabba

Raid10 for a NAS is pretty useless. Well, not useless per-se but the concern of a NAS is redundant storage and not speed. So I'd go for a Raid 5 .. especially comparing a 4 Disk Raid 10, which gives you 2TB (using 1TB spindles) or 4 Disk Raid 5, which gives you 3TB. Depending on the Raid Controller or software used, you might not be able to extend the array at a later date ...

astorrs

FYI RAID isn't likely to be an option in a SOHO device - the controller required is more expensive since the parity algorithims used are usually a lot more complex to implement.

pwjohnston

Maybe I should let you guys in on what I’m doing.

So one of my co workers got one of these;
Newegg.com - HP MediaSmart EX487, Windows Home Server w/ Intel Celeron 2.0 Ghz 2GB DDR2 1.5TB HDD, Mac Compatible - Server Systems $765

And I was thinking about getting one of these;
Newegg.com - acer Aspire Easystore H340 Intel Atom 1.6Ghz 2GB 1TB GBLAN 4 Bay Hotswap Windows Home Server - Server Systems $389

However I was convinced to go my own route which is costing me about $450 after shipping, but before HDD.

Chenbro Case 180 Watt case, 4x 3.5” hot swappable drive bays
Chenbro Micom Co., Ltd.

Intel board (does raid 0/1/5/10) also 10/100/1000 LAN
https://www.ewiz.com/detail.php?name=MB-Q45EK

Intel Dual Core Celeron E1500 2.2GHz

4GB Super Talent DDR2-800

So I’m putting openfiler on it. Openfiler - Wikipedia, the free encyclopedia

My options are RAID 0/1/5/10. I have put OpenFiler on an old system (1.2 GHZ Athlon, 768 MB ram, 500 GB IDE and set up a Software RAID 1). The MoBo I’m getting does MoBo raid and since this is only going to be for a home NAS there should be enough cycles left on the CPU to handle it.

msteinhilber

Your plan is similar to mine, except I went with an old single core Celeron 3.06 LGA775 on an Intel motherboard with a couple Intel SRCS14L 4 port raid cards that were from decommissioned servers. I know RAM is incredibly cheap, but I wouldn't spend the extra $20 or so on a 2nd 2GB stick, there just isn't any need for that. My setup only runs two 512MB modules and it works just fine.

I run RAID 5 on mine, wouldn't be the end of the world if more than a single drive fails. The data is synced in real-time to a single 1TB drive in one of my machines and once every couple of weeks I swap the 1TB drive around with one I keep in our safe deposit box (all our family photos and all of our paperwork from other the years is scanned in).

HeroPsycho

kalebksp wrote: »

I forgot the why part.

RAID 6 is like RAID 5 but gives you double parity, meaning that two drives would have to fail before you'd lose data.

*scratching head* That sounds an awful lot like RAID5...

Don't you mean three drives?

If a Windows Home Server costs you as much or less than your home built NAS, it must be asked why you're not going the Home Server route, considering all the features it would provide you over an OpenFiler box. If you need iSCSI or something like that, ok, but OpenFiler can't do image level backups of machines, provide RDP access to all computers in your house that support hosting it, enhanced media streaming capabilities, I could go on and on...

For most home users wanting a NAS, WHS has more features than any other home NAS product I can think of, and its only downside is price...

Edit: why spend $650 on the EX487 when you can get the EX485 for $500. When you can get a 1TB drive for like $70, I hardly see how the EX487, which is an EX485 with an extra 750GB hard drive, is worth the money.

tiersten

HeroPsycho wrote: »

*scratching head* That sounds an awful lot like RAID5...

Don't you mean three drives?

No. Thats RAID6 or RAID-DP.

RAID5 is a striped set with 1 set of parity data distributed across all drives and will protect against the failure of at most 1 drive.

RAID6 is similar but it has 2 sets of parity data also distributed across all drives which allows continued operation even with 2 failed drives.

astorrs

P.S. When I said RAID isn't likely an option, I meant to say RAID6 - stupid iPhone

astorrs

Tiersten, HeroPsycho and you are both right (he was referring to the number of drives that would have to fail before you loose data, which is 3)

Peibol

For HDD Newegg has (I know they are now Western DIgital, but they are cheap)

Newegg.com - SAMSUNG Spinpoint F2EG HD154UI 1.5TB 5400 RPM 32MB Cache SATA 3.0Gb/s 3.5" Internal Hard Drive - Internal Hard Drives

If u buy 2 or more, each one is 99.99 and it's 1.5TB, that's a nice price, plus free shipping

HeroPsycho

tiersten wrote: »

No. Thats RAID6 or RAID-DP.

RAID5 is a striped set with 1 set of parity data distributed across all drives and will protect against the failure of at most 1 drive.

RAID6 is similar but it has 2 sets of parity data also distributed across all drives which allows continued operation even with 2 failed drives.

How many drives have to die for RAID6 to lose data? Answer: 3.

He said two would need to die in RAID6 to lose data. That would be RAID5.

kalebksp

kalebksp wrote: »

I forgot the why part.

RAID 6 is like RAID 5 but gives you double parity, meaning that two drives would have to fail before you'd lose data.

I phrased that incorrectly. HeroPsycho, tiersten, and astorrs are, of course, correct.

pwjohnston

HeroPsycho wrote: »

If a Windows Home Server costs you as much or less than your home built NAS, it must be asked why you're not going the Home Server route, considering all the features it would provide you over an OpenFiler box. If you need iSCSI or something like that, ok, but OpenFiler can't do image level backups of machines, provide RDP access to all computers in your house that support hosting it, enhanced media streaming capabilities, I could go on and on...

Well I'm just testing OF out. If I find there is a feature or WHS I need/want than I might switch. Either way, I still have what will hopefully be good hardware and should be able to run WHS if I want.

It's only what $100 ish?

HeroPsycho

pwjohnston wrote: »

Well I'm just testing OF out. If I find there is a feature or WHS I need/want than I might switch. Either way, I still have what will hopefully be good hardware and should be able to run WHS if I want.

It's only what $100 ish?

Correct. Don't bother using RAID though with WHS. Aside from maybe RAID1 for the OS drive, RAID hinders you with WHS more than it helps you unless you have a lack of disk i/o, which is highly unlikely for most home users accessing a NAS. It has file duplication built in. Just enable it at the file share level, and it takes care of it for you.