Advice on first venture into NAS

Hi all,
I have been wanting to get a NAS for a while now and have been looking at (drooling over !) the Synology DiskStation DS1513+ , but at £620 plus disks it's a bit of a chunk of money for me to splash out in one go.
So I have just started to think about a shelf build NAS and so far the only thing that I'm certain on is the OS (OMV)

Unfortunately I have a lot of questions to ask ! so here goes ...

First of all: hardware raid or software RAID ? I have always been of the opinion that hardware RAID is the only way to go, but reading some of the posts on here makes me wonder if it is the best way to go.
What would people recommend ? could someone list the pros and cons for both ?

The setup I am thinking of doing is as follows:

1 Lian-Li PC-Q25B Case
1 Corsair CP-9020058-UK CXM Builder series 430W Power Supply
1 Kingston SV300S37A V300 60GB SATA 3 SSD
1 Asus H81I-Plus s1150 ATX Motherboard
1 Intel Celeron G1840 2.80GHz Socket 1150 2MB L3 Cache
1 Corsair Memory XMS3 Classic 4GB DDR3 1600 MHz CAS 9 (2x2GB)
1 Highpoint RocketRAID RR2720SGL
2 LSI CBL-SFF8087-SATASB-06M 0.6m
5 x WD Red 4TB (but will probably get 3 to start with)

The usage/purpose is to replace all of the storage on my main PC and HTPC, I have a SSD already in the HTPC with a 4TB & 2TB HDD, and then my main PC has 2 x WD Velociraptor 150's and 3 other drives of 1Tb 1.5TB & 2 TB.
I want to move all data from the HTPC and the main PC to a NAS and replace the 2 x WD's Velo's with a SSD.
So the most important thing to me is going to be data integrity, then speed so probably going to go with either raid 6 or 10

Memory wise is 4Gb enough, I have read somewhere about using as much as possible, but I don't see the reason for this especially if running hardware RAID, I'm guessing they say this if you are using software RAID, but surely if you go to the extremes of 16GB and use that for caching, your going to get a lot of hard faults with the ram and introduce issues ??

And lastly ... just how reliable is the whole thing i.e self build NAS + OMV ? you know the problem with researching these things is that you only really see all the issues being raised in forums.
This particular build is going to come in a few hundred pounds cheaper than the Synology DS1513+ , which is nice, but I want be able to know that I'm not going to lose my data !! ... I would really like to hear from people that have / are having really good error free results from their self build NAS.

One more lastly ! If what I have spec'd looks wrong to anybody, please chirp in and tell me !!

Many thanks

DamoB

OK Thanks for the comments, I will look into the ServerRaid card - so do you all think that proper hardware raid is still the best option ?

As far as cases go, hopefully I won't be needing to hot swap drives that often !! , size was really the main consideration, and also I think you guys over the pond get a better selection than we do here in the UK + your prices are much nicer :cry:

Thanks David .... I will have a good read when home.

Cheers all.

Damob

Thanks for the comments again David.

That's interesting that you say most would recommend software over hardware RAID, I have pretty much only ever worked with hardware RAID with servers, but have software RAID on my home PC running RAID 0 with 2 x Velociraptors just for speed ! but all important data is backed up.
I intend to keep backing up my most important data, but I also feel that with the correct RAID setup and good hardware and reliable software, having a 2 drive failure capacity would make the data pretty safe.
I'm more concerned about the OS messing up the filesystem, I have read a number of posts about the cheaper NAS units destroying the filesystem for no good reason (Drobo & QNAP have had some serious issues, Drobo especially)

Out of interest .. what do the proprietary NAS units like the Synology use, software or hardware RAID, and how does a DIY build NAS compare performance wise ?

Also, If by the sound of things OMV is setup to work with software RAID, how does it all tie in when using hardware RAID ? i.e would you need to configure the logical volumes via the RAID cards interface and then just manage the shares from OMV, or does OMV have the capability to configure and managed the RAID array from withing it's own interface ?

Sorry for all the questions, I just want to make sure i'm doing the right thing before I start spending money !!

Cheers

Damob

WOW thanks Guys (I'm assuming your are all male ! - if not I apologise)

Yet more really useful and interesting information here.

So..

Self build NAS = potentially faster/better than proprietary NAS = big thumbs up !!

SnapRAID = sounds good, but need to read up on it when home (does this replace the more conventional RAID levels and if so what is it's performance like?)

Logical Volumes - I had ideas of creating 2 volumes, 1 encrypted 1 not - but haven't investigated this yet - would that be possible ?

ServeRAID M1015 Controller - Tough to find in UK for not silly prices, also possibly not compatible with SnapRAID (I'm guessing)

RocketRaid RR2720SGL - I am assuming that this would still be better than using mobo raid controller + gives me the ability to run the SSD off the mobo and then still have the possibility of running the max amount of drives the case can hold (7) - as it's not a true hardware RAID card, would OMV be able to configure and manage the RAID from the webGUI ?

More questions !! :roll: I'll run out of them eventually

Thanks again.

Damob

Ah that's no good then .... i need the speed

Yes agreed, but I was thinking of using LAG and connecting another media centre to it at a later date, and also there would be occasions where I would be doing read/write operations on my main PC while streaming HD video to my HTPC.

D.

OK !! I get your point - I concede I may be over thinking / engineering things a bit. :?

And no I won't be running ESXi, but will be running my VMWare workstation virtual disks from the NAS - hopefully.
One of the other things that I will be doing which makes me want the fastest transfer speed possible is re-encoding a whole lot of my blu-ray rips and .mkv's - I do this by copying them from my HTPC to my main PC, doing the encoding there as it's much more powerful and then moving the encoded files back to the HTPC, currently getting an average of 35Mb/s which is not maxing out my network at all (Gbit router/switch cat6 infrastructure cabling, and Intel Gbit NICs at both ends) - this is not from my PC RAID btw, I use a Seagate 1.5Tb drive as my scratch drive and WD EZRX in the HTPC, both speed test at well over 240MB/s.

This is the thing, if you take theoretical speeds at face value, then everything seems great, but the reality is that network stack overheads and PCI\PCI-E utilisation stops things from running at those theoretical speeds, so actually you do need to over spec things a bit to get closer to what should be possible - if that makes any sense !!

Going back to a previous question - does anyone know if you can use the RocketRaid RR2720SGL card in conjunction with OMV's RAID configuration tools, and if not is it possible to install the manufacturers linux utill (if one exists) ?

Ta.

Damob