RAID-5 - is it worth it?

AngusM

AngusM

AngusM

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another "in search of advice..."

I am building a mid/high end gaming system and was thinking about using RAID-5, partly to increase reliability but I was hoping for an increase in performance over just one or two big disks.
The system will be something like:
Foxconn Mobo P9657AA-8EKRS2H (Pc-Pro A-list)
Corsair Memory TWIN2X1024A-6400 2x512MB 240-Pin DIMM XMS2-6400 (?)
Intel Core 2 Duo E6300 or E6400
...not yet decided on graphics card.

I have used both RAID-0, which was great until a drive crashed, and now use RAID-1. Should I go to 5 on this new system?
 
Triad2000 said:
Only if you use SCSI drives.

Wouldn't even bother trying to RAID SATA or IDE - they cant often cope with it and die.
Click to expand...

SATA and IDE can cope fine with RAID5, it's actually less stressful on the drives than RAID0 or 1. The main problem with RAID5 on SATA/IDE is the lack of full hardware RAID5 controllers which means that unless you spend a lot of money the write performance is quite poor.

If you're just looking for a performance boost in a gaming system then I wouldn't bother, RAID5 is great for large scale storage but you don't need terabyte scale storage then you can get better performance for less money with either single or RAID0 Raptors.
 
I personally will be getting a hardware RAID controller (Areca 1220 PCI-Express) but I will probably be using 5 or so 80GB drives (I have 4 at the moment in a RAID0 and RAID1) to create a very fast, reliable array. Might have a hot spare too.

The reason - excellent reads so it will be nippy for gaming and windows and it is also reliable enough to store important data on (hence the hot spare or possibly go RAID6 as this is virtually the same thing but with 2 parity drives).

I think it is worth it, but then again not all people do. You have to get a good card as even some hardware RAID cards are poor - however that cannot be said of the Areca RAID cards which are among the best available (possibly better than Adaptec and 3Ware, though 3Ware would give most a run for their money).
 
There is an article here:

http://tomshardware.co.uk/2004/11/19/using_windowsxp_to_make_raid_5_happen/index.html

which explains how to set up Win XP to use RAID 5, but also compares various different controllers to this 'software solution', giving some useful benchmark results. It's quite an old article but it does show the basics quite well. As rpstewart says, Raid 5 has relatively poor write performance, so is not ideal as a local drive in a workstation, but as a network archive where the network is the limiting factor then it has the benefit of more efficient use of the available space than Raid 1 or 0+1.
 
lsi megaraid 300-8x here, 6 port raid controller with 6 x 200 seagates. Fast writes & a fault tolerant 1TB (ok, about 900mb in reality). Very happy :D
 
Thanks for all the thoughts; I was thinking about motherboard RAID, though I think I may have been missled about the Foxconn mobo I mentioned - I don't think it has RAID-5. If anyone has had good experience using motherboard-based RAID-5, I would love to hear.
 
Well - I'm using RAID 5 with 3 x Seagate 250GB's on the on-board nVidia controller on the Asus A8N32Sli-D.

Write speeds - Poor.
Very poor.
But I have a scratch drive to work on and use the R5 for storage.

Read speeds - Excellent. Nearly 200Mb/s.
With 2 files on separate partitions being copied - 150Mb/s.

So copying 2 files from 2 different places on the HDD is still faster than the speed you would access 1 file from a normal HDD.

My PC is used as a file-store too, so for that purpose it is ideal.
Once a week or so I transfer stuff from the scratch drive -> RAID array overnight.

Thinking that a 3rd party RAID card would be a good investment...
But then if you are just using it for storage - Mobo based solution is indeed cheap.

Remembering that if you change mobo, 99% of the time you need to break the array and find room to put all that data.
Another reason why plug-in cards are better.

I am happy with it for now anyway. :)
(And 4 drives is significantly faster than 3 too... Just I had no room for more HDD's!)
 
RAID 5 really shines for storage with a low disk overhead (n-1) where fast right performance is not a requirement - perfect for a media and/or file store, not good for transactional databases and loading games quickly.

Hardware RAID5 solutions are nice but I have been running four 250GB WD IDE drives in this configeration using Windows 2003's software RAID solution for about two years on an old IWill board with a 1GHz Athlon (overclocked from 750MHz :D) and 768MB of RAM. You do notice large writes to the array slowing the machine down but I built the whole thing out of mostly old bits and pieces I had in the cupboard for less than a decent RAID card. This machine is running 24/7 as a file/media server and general download machine. During this time I have had a couple of issues, the first time the array rebuilt OK (took about 24 hours) cause unknown, the second time the IDE controller on the motherboard appeared to die, I switched to the secondary IDE and again the array was rebuilt without any data loss. The array appears to be portable between installations of Windows 2003 (i.e. I could plug it into another 2003 machine) but I haven't tested this. If so this does give an element of protection from a RAID card hardware failure.
 
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