RAID5 vs. RAID1 For Home NAS? *POLL*

[MichaelD]

This is a "fact-based opinion thread" and you get to vote and/or explain your rationale. This is not my first go-round with a home NAS w/a RAID array...been running one for easily 15 years.

Currently, my home NAS is W7_x64 box (overkill I know) running a 6-drive RAID6 array on a hardware RAID card (3Ware 9650SE). The drives are 500GB drives, bought many years ago when 6 of those drives cost as much as cheap, used car. Now I can buy a 4TB drive for less than one of those drives cost back then.

One drive died...awhile back. Now, I'm looking to replace them all, but drive capacity is so huge these days that I don't need to incur additional risk by having a multi-drive array if it's not needed.

I have almost 2TB of data that is precious to me and yes; the truly irreplaceable data is backed up to an external HD and BluRay discs.

This is a home file server used for file server/archiving purposes. Rarely do we stream HD video from it, but we do, occasionally.

A 2-drive RAID1 mirror with a hot spare would serve the need; secure storage. A 3-drive RAID5 array with a hot spare would also serve the need and have much faster reads and writes. This would come in handy when doing full or incremental backups. Oh...the server is on a Gigabit Ethernet link to a Gigabit switch....network is not a real bottleneck.

I understand the pros and cons of both RAID levels...and I really don't know which one to choose. Less drives = less drives to fail...that's a hard reality. But I'm very used to 90MB/s transfer speeds and would miss that.

So please post your recommendations and/or vote. Thanks in advance for your participation

 

[Red Squirrel]

I find raid1 is a waste for mass storage but is better suited for an OS drive where the data on it is rather static and all you want is redundancy. I would go raid 5, as you can easily expand by simply adding drives. Raid 10 is also nice but overkill unless you need the performance. I have a raid 5 with 8 1TB drives, and the performance is half decent for my needs. I am thinking of converting it to raid 6 though.

 

[_Rick_]

Why would you run a RAID 1 with a hot spare?
Just make it a three-drive RAID 1, then you don't have to worry about resyncs either.
The same is not necessarily true for 4 drive RAID 6 vs 3+1 RAID5, due to the different parity algorithm, that may have a slight performance penalty.
But RAID 1 with hot-spare is pure madness. You have only downsides.

 

[MichaelD]

Thanks, Red Squirrel. I have enjoyed my RAID6 array. The performance has been great (reads AND writes) and the fact that I've had one dead drive...for a long time... and STILL had no worries about my data was just great. I paid a princely sum for this RAID card (and it's battery) back in the day...it was a solid investment.

This "NAS refresh" is also sort of budget-driven. I'd love another RAID6 array but don't want to spend $800 on drives in order to wind up with more than 2TB of space (what I have now). It may wind up turning out that way though. /facepalm

 

[MichaelD]

Why would you run a RAID 1 with a hot spare?
Just make it a three-drive RAID 1, then you don't have to worry about resyncs either.
The same is not necessarily true for 4 drive RAID 6 vs 3+1 RAID5, due to the different parity algorithm, that may have a slight performance penalty.
But RAID 1 with hot-spare is pure madness. You have only downsides.

Point taken, and you're right...didn't think that one through all the way. Thanks.

ps
The hot-swap drive cage I have only holds 4 drives, but the case itself will hold at least another 6 drives, albeit with 5.25" to 3.5" adapter plates bolted on...it's a server case. So I could run a larger array, number-of-drives-wise, but see my post about $$$ above.

 

[BonzaiDuck]

I've avoided buying NAS boxes. I use an older computer and WHS-2011. I bought the plug-in to enable drive-pooling. I had a RAID5 for my server a few years back when I first started using the earlier WHS. I don't think I need it now. There's enough redundancy with the pooling.

But I can't vote with the options ;you provide, because I don't "RAID" anything anymore. This -- from a guy who spent the bucks for an expensive 3Ware controller, with a four-drive RAID5.

I never had any RAID config fail on me -- and that includes RAID0.

 

[MichaelD]

I've been into RAID for a long time, going back to the PATA HD days when I'd use the MB's onboard controller.

For my home NAS, over the years I've progressed from a WinXP box first using onboard RAID, then to a HW RAID array, to a Server 2003 box, to a FreeNAS box (too fiddly) to finally the W7 box. Running a HW RAID card, RAID 5 or 6 array and having a UPS supporting it all has been very reliable for me.

It's just time to upgrade these HDs before any more of them kick the bucket. The HDs are just about 10 years old at this point. :hmm:

I'll be going with a RAID5 array. Just not sure how many drives will be in the array at this point, 3 or 4.

I also might move to 2.5" drives, though that would mean also having to buy a 2.5" drive cage for them. Something like this most probably http://www.newegg.com/Product/Produc...82E16817994142

2.5" drives use less power and run cooler. I might even be able to get away with turning the cage's internal fan off, as most of the time the NAS's drives are spun-down.

 

[Red Squirrel]

If you want to get serious, get one of these:



:biggrin:

Not cheap though, by the time all was said and done that server probably cost close to 3k.

2.5" is actually a viable option these days too as there are plenty of cases that have a decent amount of 2.5" bays. I think I've seen some 1U boxes that can fit like 8 of them, if more.

 

[MichaelD]

I actually have a RAID card with an external port and the cable to connect to one of those storage array boxes. Back in the days of 500GB HDs I could've used one of those. But not now. It sure is way cool to drool over, though!

I'm scouring EBay now looking for deals on 2.5" HDs. Not many to be found! Plenty of good deals on regular 3.5" drives, though.

I think I'd like to move to 2.5" drives...the technology is mature enough, most come w/a 2 year warranty and they run cooler/use less power as well.

 

[dave_the_nerd]

I voted for Raid5, but my opinion really depends on how much you intend to grow your data footprint, and if you intend to continue using Windows as your server OS.

Four 2TB 2.5" drives in a RAID-10 would give you 4TB of useful space, good fault tolerance, quick rebuilds, and would fit in a single 5.25" bay. You could do a RAID-5 with them instead and get 6TB usable space. But if you'll never use >4TB, there's no point in dealing with the hassles of striping/parity.

I would take a look at using Windows software RAID vs. your hardware RAID card, too. If the performance is good enough, the software RAID has some advantages wrt disaster recovery (after your RAID card dies, for instance.)

Honestly, if your server has sufficient CPU, your network is still the bottleneck. Even a single 3.5" HD these days can read >125MBps.

 

[MichaelD]

@Dave: That's the best price I've seen on that model of 2.5" cage...yet another reason for me to go to 2.5" The only thing I don't like about that cage is that you can't turn the fans off, though I could remove them if I wanted. 40mm fans are typically screamers...though those might not be.

Eventually I will have more than 4TB of data, most of it HD video files. But for now 4TB of space (what I'm aiming for) will suffice for the next couple of years or so.

I will look into Windows SW RAID; I haven't done so in a long time b/c last time I checked there was no substitute for true HW RAID. RAID card with a battery-powered cache, running off a UPS makes for a sound sleep at night for me.

 

[cbn]

I also might move to 2.5" drives, though that would mean also having to buy a 2.5" drive cage for them. Something like this most probably http://www.newegg.com/Product/Produc...82E16817994142

Four 2TB 2.5" drives in a RAID-10 would give you 4TB of useful space, good fault tolerance, quick rebuilds, and would fit in a single 5.25" bay. You could do a RAID-5 with them instead and get 6TB usable space. But if you'll never use >4TB, there's no point in dealing with the hassles of striping/parity.

Nice, both those 4 x 2.5" backplanes use only 1 power connector for 4 SATA drives. (The top one uses molex and the bottom SATA).

The one I remember looking at required two molex power connectors for 4 x 2.5" drives in a 5.25" cage.

Too bad 2.5" HDD are so expensive at the 2TB level. (Eg, 2TB WD Green 2.5" HDD= $180 vs. 2TB WD Green 3.5" HDD= ~$90).

 

[MichaelD]

Yep, I noted those things as well, Comp Bottleneck. I like the 1 SATA power connector vs. 2 Molex very much.

And it's too bad about the price of 2TB 2.5" drives, though I'm just going to have to suck it up, most probably. Like every other computer part I've ever bought, the price of 2TB drives will drop by 25% across the board 2 weeks after I buy mine. /facepalm

 

[Carson Dyle]

You only have 2TB of "precious data"? You shouldn't be using RAID unless uptime is critical to you at home for some odd reason. I'm guessing pics of the grandkids aren't needed 24/7. Just do regular backups.

If you insist on RAID, just do RAID1 with a cold spare. That would be the simplest and cheapest option by far. And keeping it simple will lessen the overwhelming probability that you're going to **** up and trash the whole array when you have a drive failure.

 

[Cerb]

You only have 2TB of "precious data"? You shouldn't be using RAID unless uptime is critical to you at home for some odd reason. I'm guessing pics of the grandkids aren't needed 24/7. Just do regular backups.

If you insist on RAID, just do RAID1 with a cold spare. That would be the simplest and cheapest option by far. And keeping it simple will lessen the overwhelming probability that you're going to **** up and trash the whole array when you have a drive failure.

Why RAID 1 with a cold spare? A straight up RAID 1 would be superior to that in every conceivable way, if you wanted to use 3 drives in that kind of configuration.

 

[Carson Dyle]

Why RAID 1 with a cold spare? A straight up RAID 1 would be superior to that in every conceivable way, if you wanted to use 3 drives in that kind of configuration.

I don't know what you mean. I'm talking about RAID1 with two drives and an offline spare sitting in a bag on a shelf.

 

[MichaelD]

Yep, roughly 2TB worth of pictures and videos dating back to 1940 or so. 8mm tapes converted to VHS, then to DVD then finally digitally archived. The original tapes and photos are long gone in most of the cases. Trust me, you can fit a lot of 1MB-ish photos in 2TB of space. Of course there's also data like tax returns, business documents, etc. Oh, and of course my 120GB of MP3s, most of which I ripped, by hand, one by blessed one from the original CDs. That took a year, IIRC. All of it precious.

The data is irreplaceable in most instances. There's also the TIME it's taken to get all this together. I've had this 3Ware 9650 for years. I've never not been able to rebuild from a failed drive, though I do know that will be an eventuality. RAID is not backup. I also have a fairly decent backup strategy for the really vital stuff mentioned above. All the game maps, benchmark utilities etc that I can just DL again, I don't back up...saves on backup space.

Most probably I'm looking at going w/a 4-drive RAID5 w/hot spare.

ps
Uptime is 100% critical for me. I want all of my data available all the time. I am willing to spend the money on HW and electricity to make that happen. I can't be bothered digging thru thumb drives and ext HDs looking for a particular file. I have a great folder structure on my NAS...it works for me. YMMV.

 

[Carson Dyle]

Why use RAID? Are you using and adding to this data constantly, 24/7? And why so many drives to store what can fit on 1/2 of a single 4TB drive? For speed, so you have very fast access to those 1940s movies?

I would devote more energy to keeping backups and only backups. Keep at least two, with one of them offsite in a safe place.

It just never ceases to amaze me that so many people devise problems for themselves that don't exist.

 

[MichaelD]

It's not a problem for me; I've been working with RAID for 15+ years both at home and for a living (not saying I'm an expert).

For me, RAID + backups is the ultimate in data security. It is highly unlikely that I'll lose the array completely (battery-powered cache on RAID card and UPS on the server). In the event that I do, I have backups.

My wife works from home and stores her data on the NAS. Sometimes we'll stream video from the NAS. I work from the NAS when I work from home as well. I found that I/O from a single HD wasn't cutting it. For me, it's not about finding the bare minimum necessary to get it all done. It's about finding something that meets all my needs with some room to spare and is reliable.

 

[Cerb]

I don't know what you mean. I'm talking about RAID1 with two drives and an offline spare sitting in a bag on a shelf.

Ah. I was inferring that to mean a spare ready to be told to come online.

 

[Red Squirrel]

Why use RAID? Are you using and adding to this data constantly, 24/7? And why so many drives to store what can fit on 1/2 of a single 4TB drive? For speed, so you have very fast access to those 1940s movies?

I would devote more energy to keeping backups and only backups. Keep at least two, with one of them offsite in a safe place.

It just never ceases to amaze me that so many people devise problems for themselves that don't exist.

I would NEVER put data on anything but raid. Drives fail. Yeah you can have backups, but then you're still stuck rebuilding the file system and putting all the data back, fixing all the file permissions so they match whatever is needed such as if you have different groups/users with access to different files, etc...

With raid you just remove the failed drive, pop another one in, and let it rebuild. You lose nothing. I guess I'm just impatient. I like to be able to do things the easy way.

Another fun thing with raid is live transformations and disk changes. I've replaced every single drive in my array due to failures or w/e, and never had to touch any form of backup, or copy any files anywhere, and my data was always accessible. Can also grow arrays or even change type. I have not tried yet, but it's also possible to replace drives with bigger ones, and increase the size of the array that way too. All live, without losing access to data.

 

[MichaelD]

Better than I could've said it myself. Thanks.

I would NEVER put data on anything but raid. Drives fail. Yeah you can have backups, but then you're still stuck rebuilding the file system and putting all the data back, fixing all the file permissions so they match whatever is needed such as if you have different groups/users with access to different files, etc...

With raid you just remove the failed drive, pop another one in, and let it rebuild. You lose nothing. I guess I'm just impatient. I like to be able to do things the easy way.

Another fun thing with raid is live transformations and disk changes. I've replaced every single drive in my array due to failures or w/e, and never had to touch any form of backup, or copy any files anywhere, and my data was always accessible. Can also grow arrays or even change type. I have not tried yet, but it's also possible to replace drives with bigger ones, and increase the size of the array that way too. All live, without losing access to data.

 

[Carson Dyle]

I would NEVER put data on anything but raid. Drives fail. Yeah you can have backups, but then you're still stuck rebuilding the file system and putting all the data back, fixing all the file permissions so they match whatever is needed such as if you have different groups/users with access to different files, etc...

Do you need to be reminded? He has ONE freaking drive full of data.

If you don't realize how trivial it is to backup and copy file permissions, then it's little wonder you're equally misguided.

If you like playing with technology, RAID is awesome. Pretend your home file server with one disk drive worth of valuable data is a critical corporate server at Exxon. Knock yourself out.

 

[smitbret]

Yep, roughly 2TB worth of pictures and videos dating back to 1940 or so. 8mm tapes converted to VHS, then to DVD then finally digitally archived. The original tapes and photos are long gone in most of the cases. Trust me, you can fit a lot of 1MB-ish photos in 2TB of space. Of course there's also data like tax returns, business documents, etc. Oh, and of course my 120GB of MP3s, most of which I ripped, by hand, one by blessed one from the original CDs. That took a year, IIRC. All of it precious.

The data is irreplaceable in most instances. There's also the TIME it's taken to get all this together. I've had this 3Ware 9650 for years. I've never not been able to rebuild from a failed drive, though I do know that will be an eventuality. RAID is not backup. I also have a fairly decent backup strategy for the really vital stuff mentioned above. All the game maps, benchmark utilities etc that I can just DL again, I don't back up...saves on backup space.

Most probably I'm looking at going w/a 4-drive RAID5 w/hot spare.

ps
Uptime is 100% critical for me. I want all of my data available all the time. I am willing to spend the money on HW and electricity to make that happen. I can't be bothered digging thru thumb drives and ext HDs looking for a particular file. I have a great folder structure on my NAS...it works for me. YMMV.

IMHO, RAID 1 is a pointless investment in HDDs for home use. Unless you have the Brady Bunch all simultaneously bombarding the server with data requests all day, there is no real world performance advantage to a RAID 1. RAID 5 or maybe RAID 6 if you really want to be careful is sufficient for 99% of home use. Drive dies then array stays online till you get a chance to throw a new HDD in there and start the rebuild before everyone goes to bed at night.

Having been down the hardware RAID route and left it, it really sounds like you should be looking into something like this instead:

www.flexraid.com

or

www.lime-technology.com

or

http://snapraid.sourceforge.net/

Data is not striped across the drives so that if you get a catastrophic crash, data is still intact on any drive that is still working. You said that you had already set up a file structure that you were comfortable with and with FlexRAID, you can just import your already existing drives into the array and keep the data on it.

Additionally, since you only have a couple of TB of data you could just start with 3x1TB HDDs or maybe even 2TB and then as your needs grow, you just throw in another drive and reinitialize. The added space is just added to the pool.

Then, with the money you saved by not wasting resources on a RAID 1, make sure you are backing up to a 3TB external at least once or twice a week.

I guess since it's only 1 drive worth of data, you could just run a RAID 1 until you've outgrown the space and then just add a 3rd drive and move to RAID 5 at that point.