Small business NAS build - help/recommendations

[batfastad]

Hi everyone

Our old Lacie Ethernet Disk NAS system has just decided to die so it's time for a replacement.
It was only a matter of time, it's been absolutely mullered since we bought it back in 2004

We're a small business with about 20 users who'll be accessing the device.
Still deciding on the OS but I'll either go for a pre-done Linux environment like OpenFiler or FreeNAS
Or just do it myself with Ubuntu server or CentOS or something else. Ubuntu Server probably because we can mess around with that easier and customise it more.

I always find motherboard/processor/memory difficult because things move so damn fast these days!
But here's what I've got so far...

Case: Chenbro 2U, 8 SATA hot-swap (RM21508B)
8 hot-swap bays, another internal drive for the OS

RAID Card: 3Ware SATA II 8 port (9650SE-8LPML)
I realise software RAID could probably handle this perfectly, but I like the re-assurance of going with hardware RAID.

Drives: Seagate 500GB ST3500320AS
I think these are SATA II drives and are listed on the 3Ware compatibility list on the 3Ware website.

Now here's where I need some help/advice:

1) RAID level
I want to go mirroring (RAID 1) but this has to be a nested RAID level (RAID 1+0) because I want to use the 500GB drives to increase capacity (4 x 500GB drives... 1TB capacity)
According to the wikipedia article on Nested RAID, RAID 1+0 is slightly preferred over RAID 0+1 for reliability.

Or do I go for some sort of RAID 5 with parity... for ultimate reliability?

2) Motherboard / processor / memory
Being a NAS, this box doesn't have to be super-powered. The data processing should get done by the hardware RAID card. So we're not looking to pay a premium for latest processor tech, but something fairly decent would be good. And since memory prices are cheap these days, makes sense to go for 4GB really.
The RAID card is PCIe rather than the older PCI-X

Any other suggestions / comments on this?
Obviously RAID does not equal a backup, we will always have backups of recent/important files

Thanks, B

[FifthFreedom]

Ok, The Case and the drives you have chosen look fine.

I assume Seagate is a personal preference of yours and there not bad drives...

When it comes down to RAID, I would be tempted to use Raid 5 as you would be keeping all your data safe with reasonable R/W times.

But obviously you pay the price of loosing a drive with RAID 5 so if you use 8 drives, that would be 3.5 TB of physical storage space.

You'll need an EATX mobo for this build and this really comes down to the exact spec you need and of course the price.

Where were you planning on buying these parts from?

[batfastad]

Case (including back plane), power supply, RAID card all from the same supplier (servercase;co;uk)
I can't post URLs in my posts yet

Initially I wanted to go for only 4x500GB drives, then upping the capacity later.
So for RAID 5, that means I need 5x500GB drives to give me 1TB of capacity?

Thanks for the hint on RAID 5, I'm not clued up on RAID with parity but I've heard it's a good thing!

Well spec/price is sort of up in the air.
Could I get server grade motherboard/processor/memory for £250-£300?

Thanks, B

[FifthFreedom]

I've never used that site before but from my quick browse it looks like quality parts at good prices...

Using RAID 5 you would have 5 Drives of 500Gb.

500Gb would be used to store the Parity so in effect you would have 2TB of storage.

But the upside is, if any one drive fails you can re-create the data from the Parity segements scattered over the other disks. The only issue with RAID 5 is if a second drive fails before you've recreated a first failed drive then the RAID is destroyed and all data is lost.

When it comes to specs, it depends whther you want to go the Xeon route as to how much you spend.

[LegacyOne]

that means I need 5x500GB drives to give me 1TB of capacity?

3x500GB drives in RAID 5 would give you 1TB and allows one drive to fail.

RAID 6 with 4x500GB drives would give you 1TB and allows two drives to fail.

[batfastad]

Right ok
Yeah I stumbled upon that site, called them up earlier and he seems to know what he's talking about. Gave me some useful advice on the backplane/multilane card situation.

Maybe RAID 6 is more what we're looking for. I'm paranoid about a double disk failure now.
What would you guys recommend?

Both RAID 5 and RAID 6 offers greater redundancy than a simple RAID 1+0 right?

Is it advisable for all drives to be the same make/model?

When replacing a drive in the RAID array, should it be the same make/model as the rest?

Is it worth going the Xeon route for a file server?
Or would a normal dual/quad core processor do? I suspect that a Xeon is over-speccing a bit really.

I'll be building up a new e-mail server in 6 months and that would need a bit more grunt to it.

Thanks, B

[Lourdes]

I use RAID6 or RAID5 + Hot Spare (a drive to took over immediately), the extra redundancy is reassuring.
I would definitely advice going with 1TB drives, Samsung F1's or Western Digital GP RE2's (5400rpm but in a multi-drive RAID 5 NAS the network is the weakest link). The advantage of alrger drive is obviously the additional space but if budget is a cocnern you can start with fewer drive and then expand the array with more.

Drives can all be different but they will operate at the speed and capacity of the lowest one. A mix can be good, it does no harm and can actually be a good thing if you later find one model has reliability issues or one batch is problematic.

For a fileserver with hardware RAID card the spec of the host PC doesn't matter, you could use a Pentium 2 if you wanted. One thing I would suggest is a decent server NIC with TCP/IP offloading.

[FifthFreedom]

RAID 6 is definitely more robust than RAID 0+1 or 10.

This is because in RAID 6 you can loose two drives and still your data is safe whereas, if you loose two drives in 0+1 and one is on each side of the array then your data is gone.

Still, if you have already backed up, RAID 5 would still be enough for some people.

How powerful you need the server to be is up to you.I wouldn't go with a Xeon if it was just a simple NAS I was building but sometimes my servers have been multiuse where the extra horse-power is useful.

A good idea is to look at what you have had previously and think if you want this one to be faster or not. but as the guy above me said, the really important part is the RAID hardware as this does all of the grunt of the work.

[LegacyOne]

Is it worth going the Xeon route for a file server?
Or would a normal dual/quad core processor do? I suspect that a Xeon is over-speccing a bit really.

A E4600 in a G33/G35 Board using the PCI-E slot for the RAID card will do.

[batfastad]

Ok this is getting interesting now.
Thanks for all your help so far!

Definitely seems Xeon/quad core is out of the question... plain old dual core will be more than adequate.

Final batch of questions:

1) Additional hardware/cards required.
We're going to be running custom backup jobs of our current files (say the folders of the next 6 issues of the magazines) and we could do this over USB2 or Firewire 400.
Is it worth sticking a Firewire 800 card in there for good measure? We only have 1 external drive with Firewire 800, but it could be useful in the future? Is it on the increase or is it looking like Firewire 800 will never really catch on?

Or how about eSATA sockets? Is there a sort of blanking plate you can get to convert the motherboard's SATA sockets into eSATA?

2) RAID 1+0 vs RAID 6
I'm going to go with a RAID 6 set-up. 4 x 500GB drives = 1TB of actual space.

But what I don't get, is how with 4x500GB drives, the usable capacity of a RAID 6 is 1TB, and also with RAID 1+0 it's also 1TB?

What happens to the parity information with RAID 6?
Does that not take up space on the drives?

3) Replacing RAID controller
When the RAID controller dies, does that mean the data disappears with it?
Or can you buy a new/different card, plug all the drives in, tell the card it's RAID 6 and it just carries on as before?

Also, the reason I've chosen 500GB rather than 750 or 1TB is on price/quantity of drives.
At the moment 500GB are around £50.
Our previous NAS device was 400GB total so 1TB should be enough for a couple of years, and there will be 4 spare drive bays for further expansion.

Thanks, B

[LegacyOne]

2) RAID 1+0 vs RAID 6
I'm going to go with a RAID 6 set-up. 4 x 500GB drives = 1TB of actual space.

But what I don't get, is how with 4x500GB drives, the usable capacity of a RAID 6 is 1TB, and also with RAID 1+0 it's also 1TB?

What happens to the parity information with RAID 6?
Does that not take up space on the drives?

RAID 6 is like RAID 5 but with the parity doubled and put on two drives which takes up more space.

RAID 5 with 4x500GB drives would give you 1.5TB
RAID 6 with 4x500GB drives would give you 1TB

RAID 1+0 I can't see how this is RAID 1 & 0 as two 500GB in RAID 0 is 1TB but two 500GB in RAID 1 is 500GB? So I don't see how that works but RAID 1+0 its not expandable like RAID 5 or 6 is.

3) Replacing RAID controller
When the RAID controller dies, does that mean the data disappears with it?
Or can you buy a new/different card, plug all the drives in, tell the card it's RAID 6 and it just carries on as before?

If the RAID controller dies its unlikely that it could take out the RAID be it can happen and same goes for the PSU, but yes buying another RAID card that is the same or backwards compatible would see the exiting RAID.

[peterb]

USB2 is supposed to have a transfer speed of 480Mb/s (60MB/s) while Firewire 400 and 800 are (not surprisingly) rated at 400Mb/s and 800Mb/s so firewire 800 will be faster.

However that might not be the limiting factor - this article (although referring to a Mac) gfives some useful info.

USB 2.0 versus FireWire

However for that amount of data, and in a commercial environment, you might want to consider tape back up. Although the initial investment in hardware is high, an LTO4 tape can store 1.6TB on one tape, and give transfer speeds of up to 240MB/s transfer speed (under optimum conditions.

This is just one of many LTO/Ultrium manufacturers, but gives you an idea of the capabilities.

HP LTO-4 Ultrium Data Cartridges - Overview & features

[batfastad]

Right ok, RAID 6 it is. I like the way the space efficiency of RAID 6 increases the more discs you add as well.

So the replacement RAID card would probably need to be the same vendor and backwards compatible then. So just buying any old RAID 6 compatible card as a replacement won't work.
I guess that's the advantage of buying one from a large manufacturer... I've heard 3Ware are one of the good guys for RAID hardware.
I was thinking of going for this card... Authority in SATA, Serial ATA Raid 5 Controllers the 8 port multi-lane version


Just need to decide on exact mb/processor/memory combination now.
So if I go for this processor...Intel Core 2 Duo E4600 Intel Core 2 Duo E4600 Socket 775 2.4GHz (800MHz) L2 2MB Cache Retail Boxed Processor - Ebuyer

Can someone do me a huge favour and find some compatible motherboards on ebuyer/dabs that would be suitable?
Suitable for a 24-7 hammering.
Obviously onboard audo doesn't need to be 30.1 channel surround sound. But it needs PCI express for the RAID card, 4-8GB of memory expansion, a bunch of SATA II sockets for the OS drive, and an IDE socket for a slimline DVD drive.

And also some memory?

Things move so quickly in processor/memory/mb specs that I never have time to keep up on what's current.

Thanks for all your help so far!

EDIT: I did think the difference in USB 2 and Firewire on Macs was because of some dodgy tactics by Apple which makes USB look far worse... making people buy firewire devices and forcing manufacturers to pay Apple the firewire license fee. I had heard that Firewire 800 was very very fast though, so it might be worth sticking a FW800 PCI card in there as well.

I'm just not sure about tape. At any one time the amount of data we would need to back up would be maybe 60GB. That would be everything we're working on at that moment, so that would smash across eSATA pretty rapidly.

[badass]

Whats your budget?
SATA disks pop a lot more than proper enterprise disks like SCSI and SAS disks. However they are a huge amount more expensive adn not available in such large capacities.

[DanceswithUnix]

I would check the guarantee on those hard drives, I remember a couple of years ago only Samsung offered a 24/7 operating profile on their hard drives making them effectively server class. Others have small print saying the drive was rated for an average of so many hours a day (I think it was eight, a working day). I think Western Digital have a special range of IDE/SATA "Enterprise" drives which are rated for always on.

All drives have their horror stories, but Samsung have long been a favourite for TiVo digital video recorder operation partly for returns policy and partly for cool & quiet running (a TiVo literally never ever stops recording to hard drive).

[LegacyOne]

Right ok, RAID 6 it is. I like the way the space efficiency of RAID 6
Can someone do me a huge favour and find some compatible motherboards on ebuyer/dabs that would be suitable?
Suitable for a 24-7 hammering.
Obviously onboard audo doesn't need to be 30.1 channel surround sound. But it needs PCI express for the RAID card, 4-8GB of memory expansion, a bunch of SATA II sockets for the OS drive, and an IDE socket for a slimline DVD drive.

And also some memory?

Intel EVA COVE iG35
Intel EVA COVE iG35 Socket 775 onboard graphics 6 channel audio mATX Motherboard - Ebuyer
Corsair 4GB Kit (2x2GB) DDR2 667MHz (no need for 800MHz)
Corsair 4GB Kit (2x2GB) DDR2 667MHz/PC2-5300 Memory Non-ECC Unbuffered CL5 Lifetime Warranty - Ebuyer

What do you mean by slimline DVD drive? you can't use a laptop DVD drive.