Software Raid 5 vs Hardware Raid 5

[The Sly Syl]

I've been highly considering a Raid 5 array for my next computer; I'm currently looking at 6x 500 gig harddrives for a total of 2.5~ terabytes. (S-ATA 3.0 and 16 mb cache; either WD or Seagate)

In doing motherboard research; i've discovered that some of the newer nvidia chipsets allow for Raid 5. I'm going to assume it's a software based raid 5. I remember from past discussions that software Raid 5 simply wasn't worth the hassle due to the fact that it took an immense amount of CPU utlizilation in the past.

However; considering i'm looking at a Q6600 and 4 gigs of ram. (Vista 64 ultimate) just how much cpu utilization are we talking about here? Likewise ~ More importantly; what kind of performance differences does software raid 5 have compared to a hardware Raid 5?

I'm looking at a cheaper Raid 5 card as it is; i can't afford a server-array raid card. I've seen some lower ones go for $150-$200; but i don't know how these compare at all to the worthwhile raid 5 cards. I don't particularly have any worry about Write-speed. (As i've heard raid 5 is much slower in that regard) but Read speed is something that I'd prefer to have improved over a standard harddrive setup.

 

[Fullmetal Chocobo]

Well, I can not provide information via personal experience, as I have never ran any RAID array off of the motherboard, but I have heard that the performance difference between software vs hardware RAID 5 is drastic. I'm sure someone has links to benchmarks for comparison, but I do not have any available.

If I may ask, what is this machine going to be used for? On something like a simple file server, then RAID 5 performance wouldn't matter too much, as it is simply a large cache for files. Just thought I'd ask as I didn't see the machines purpose anywhere in the OP.

 

[Gannon]

Originally posted by: The Sly Syl
I've been highly considering a Raid 5 array for my next computer; I'm currently looking at 6x 500 gig harddrives for a total of 2.5~ terabytes. (S-ATA 3.0 and 16 mb cache; either WD or Seagate)

In doing motherboard research; i've discovered that some of the newer nvidia chipsets allow for Raid 5. I'm going to assume it's a software based raid 5. I remember from past discussions that software Raid 5 simply wasn't worth the hassle due to the fact that it took an immense amount of CPU utlizilation in the past.

However; considering i'm looking at a Q6600 and 4 gigs of ram. (Vista 64 ultimate) just how much cpu utilization are we talking about here? Likewise ~ More importantly; what kind of performance differences does software raid 5 have compared to a hardware Raid 5?

I'm looking at a cheaper Raid 5 card as it is; i can't afford a server-array raid card. I've seen some lower ones go for $150-$200; but i don't know how these compare at all to the worthwhile raid 5 cards. I don't particularly have any worry about Write-speed. (As i've heard raid 5 is much slower in that regard) but Read speed is something that I'd prefer to have improved over a standard harddrive setup.

I would go hardware myself and simply eat the cost upfront, promise makes excellent fairly cheap RAID 5 devices. I use an older Fastrak S150 SX4, with 4x160GB hard drives, you can probably find used fairly priced RAID 5 controllers on ebay.

You don't really need a super duper RAID 5 card, most websites are basically snake-oil salesmen in regards to RAID 5 'performance'. If you're not willing to spend the bucks yet you want 6 500GB hard disks ($100x6 = $600) if you're not willing to invest in a RAID 5 card then go the software route but I wouldn't recommend it just because hardware RAID 5 is usually much better from a management perspective, especially with the ease of rebuilding should something go wrong. I had one drives partion error fail and it rebuilt flawlessly.

 

[KingGheedora]

I had some discussion on this same topic in one of my threads. Yuppiejr has some info on using software RAID5, and why some people might get low performance (see his post on the morning of 08/09/2007): Text

 

[The Sly Syl]

It's mainly going to be for personal use; but I'm also planning on using it for HD DVR; and considering the size of 1080p files ~ I can easily imagine going through a terabyte or two rather quickly. 2 tera to 2.5 tera seems the most cost effective at the moment; and should prohibit any possible upgrades in next year or two. Likewise, the raid 5 is for redundancy so i won't lose any of the wonderful things that will be using up over a terabyte of space. (Not to mention; a "single" drive will drastically make file management esaier on me; as my current 3 seprate harddrive management is a pain; and i'd like to avoid moving things between harddrives again)

So i'm not looking anything near server persomrance; I mainly want read speed more than write speed. As long as i can theoretically rip 720p onto it fast enough; write speed should be fine.

I'm thinking that if i go the hardware route; it will cost a could hundred more; but might be more beneficial in the long run. Software would mean that i wouldn't have to buy an SLI (or crossfire) motherboard as well as not having to buy a controller card. Which is why i'm pretty concerned about how drastic of a difference this is. Especially compared to not using RAID at all.

I can imagine the most harddrive intensive scenario i might come across is downloading a torrent while streaming video to a 360 and attempting to play a game at the same time. (As well as other not so harddrive necessary stasks run; but probably i would have media player with music.)

I'm planning on populating the other PCI-E 16x slot with an 8800GTS640mb or 8800GTX 758 depending upon price and funds.

 

[The Sly Syl]

http://forums.storagereview.ne...ex.php?showtopic=25786 <- this article; as well, brings up points that make me more interested in onboard RAID. (In which case i'll just go for a 5x500 gig setup and have 2~ tera of space instead of 2.5)

 

[yuppiejr]

Yep, I can confirm that there are some caveats to using RAID5 on an embedded chipset controller (in my case, Nforce 430) - per the SR article linked above this Microsoft article has what I think is the key bit of information regarding configuring the partitions:

http://support.microsoft.com/kb/929491

Essentially, on board RAID5 seems to work best in a 3 or 5 disk array, 32k stripe size in the array configuration with a 64k cluster size when you format the drives. You MUST use the method noted above in the Microsoft article to partition your array drives after you've set up the drives/stripe size in the array manager unless you are using Vista.

 

[The Sly Syl]

Well; I'm planning on using Vista 64 ultimate (for multiple reasons) is that how it uses it's default setting?

I'm also going to need to do some more research to see if an Nvidia chipset is better overall compared to the new Intel chipset (P35 i think) that looked quite sexy. Raid5 being adequate is something that i'm hoping to make possible with this machine.

 

[The Sly Syl]

Alright; so, basically ~ If i format the harddrives correctly; the software raid 5 should suffice? (As long as i follow the directions in that StorageReview link).

 

[JohnVM]

Funny you mention this. I'm running basically your exact rig - Q6600 with 4GB RAM and 6 500GB hdd's in RAID using onboard controller. I'm having some issues though - read here: http://forums.anandtech.com/me...=2083038&enterthread=y

I've seen pretty decent performance so far out of it - although my individual needs arent really for super huge sequential-read speeds (I basically just have a shitload of data I need decent seek times on).

Anyways, my problems mentioned in that other thread are pushing me closer and closer to buying an Areca raid card (I'd probably however get the 16 port one which is close to $1000...). I don't want to - performance wise I don't need it either, but this onboard raid, so far, is not working for me.

 

[The Sly Syl]

That's the problem for me; is i want around 5-6 harddrives; yet a RAID card that is over 4 ports is incredibly expensive. I can't afford a raid card for around $500, all of the money being used for this computer is a fluke anyway. (full replacement cost for my old computer crashing ($1300) - actual repair/upgrade cost ($250) + Money i'm getting from selling old/now upgraded computer ($900)) So i'm really trying to stay close to my $2000ish figure at the moment. I'm a college student with an only adequate job; i just need a computer that'll last me till i'm OUT of college.

 

[imported_Baloo]

Plan to use Vista for an HD-DVR. Then let me be the first to warn you that Vista has content protection that prevents user from viewing hd content in hd resolution with very few exceptions. This is true even of content that has no protection of it's own. linky

 

[The Sly Syl]

So, if i was trying to run a 1080p or 720p AVI or mp4 file; (Perhaps with AAC 5.1 or 7.1 audio) it would degrade the quality of it? What the ****.

 

[DavidXanatos]

I'm going to buy a quite similar setup, but with a bit more RAM and a few less HDD's (4 instead of 6)
I don't know if I should use the Intel Onboard RAID 5 or spend 360? on this controller: http://www.promise.com/product...%20HBAs&product_id=156

What is Important for me is a good write performance not only read performance (as far as I known an not defective raid 5 Array don't need much CPU for reading as no XOR operations are needed, only reading from a defective array or writing to a array needs those)

I tried some longer time ago a RAID 5 using windows server 2003 in software this was very painfully took up almost 100% of an A64@2.4 (single core), but i don't know how software raid over the OS compares to a RAID over the chipset (i975X)
Can I expect that a Raid 5 over the chipset needs only slightly less CPU than a RAID over Windows, or is it noticably better?

Finally how big is the advantage of a RAID with an IO CPU over an onboard one?

last but not least,
Can I using the above meant controler somehow later on extend the array to 8 HDD's without loosing the data on the first 4 HDD's (I know when I backup all data that's not a problem (excepted time) and I should do a backup anyway)

David X.

 

[Madwand1]

Intel on-board RAID 5 generally performs better than nVIDIA on-board RAID 5, and is less sensitive to the number of drives and stripe size, as I showed in a link in the SR thread.

Intel also has the "Matrix RAID" feature, which lets you do something potentially helpful here -- create a separate RAID 0 array. This can be used for high-speed captures, editing, etc., when you want to be sure of the performance. After that, you'd want to transfer the data over to RAID 5 to reduce the risk, and this part would be somewhat slow because you'd be seeking across the same drives back and forth during the transfer.

Intel ICH9x and Vista, XP-64, and 2003 can break the 2 TiB limit for a single volume.

XP-32, and nVIDIA (AFAIK) can't.

nVIDIA has better array expansion features than Intel.

Good, add-on controllers (e.g. Areca) have better performance, reliability and support.

But "RAID alone is not a backup", regardless of the quality of the implementation. With any of these, you could lose your entire array, and if you have TB's of data, you're carrying a lot of risk. The risk is greater with on-board implementations.

 

[dclive]

Originally posted by: The Sly Syl
I've been highly considering a Raid 5 array for my next computer; I'm currently looking at 6x 500 gig harddrives for a total of 2.5~ terabytes. (S-ATA 3.0 and 16 mb cache; either WD or Seagate)

In doing motherboard research; i've discovered that some of the newer nvidia chipsets allow for Raid 5. I'm going to assume it's a software based raid 5. I remember from past discussions that software Raid 5 simply wasn't worth the hassle due to the fact that it took an immense amount of CPU utlizilation in the past.

However; considering i'm looking at a Q6600 and 4 gigs of ram. (Vista 64 ultimate) just how much cpu utilization are we talking about here? Likewise ~ More importantly; what kind of performance differences does software raid 5 have compared to a hardware Raid 5?

I'm looking at a cheaper Raid 5 card as it is; i can't afford a server-array raid card. I've seen some lower ones go for $150-$200; but i don't know how these compare at all to the worthwhile raid 5 cards. I don't particularly have any worry about Write-speed. (As i've heard raid 5 is much slower in that regard) but Read speed is something that I'd prefer to have improved over a standard harddrive setup.

I wouldn't worry so much about CPU utilization or drive speed as I would about other issues - poor drivers, inability to move the RAID set to another motherboard (what if you upgrade to an Intel-chipset motherboard?), etc. FWIW, ONE 500GB drive can easily support 3 shows recording to it at once - bear in mind you're only talking about writing 9GB in an hour, and frankly, that's trivial stuff. "Even" in highdef, imagine you have a dual tuner card - that's only 12GB of writing in a full hour - that's easy.

When you said 'software', I'd initially thought you meant Microsoft RAID - ie the RAID built into 2003. Then I saw Vista, so that put an end to that ...

You might check eBay for used RAID cards. I used to be into RAID, but then it got to be too much of a hassle and for the little to no performance benefit in a one-user environment, I switched to simply using 500GB drives.

Another thought - use mount points (can Vista use mount points?) and mount volumes like so (yes, it isn't ideal, no, it isn't as nice as RAID, but it's free in MS's 2003 OSs, and may be in Vista... haven't looked)

500GB Disk 1 Here, mounted as D:
|
|------> d:\500GB2 houses another 500GB drive
|
|------> d:\500GB3 houses another 500GB drive

... and so forth....each time you add a drive, D: gets a new directory to hold the contents of that drive. There is no sharing of data across drives, so there's no risk of "lose-one-drive, lose-all-your-data", and it works with any disk controllers - the OS handles everything.

But yes, from a MCE point of view, having one huge drive is easiest to administer and use.

FWIW, I'm at 77 recorded shows on a VistaMCE with 211GB free (of 500GB), so assume almost 150 shows recorded at one time (1 hour each) on a 500GB drive. That's a lot of TV.

Bear in mind Vista MCE can show content of Recorded TV from multiple folders and volumes with some registry hacking, but can only record to one of them, something I'd like to see fixed (If freespace =< 6GB, record to second volume...)