RAID what?

[D_o_S]

Hi,

I have 4 WD Raptors 740GD. Now, my question is, how should I RAID them, and on which controller? I want maximum performance.

This is on a DFI Lanparty nF4 SLI DR Expert mobo.

TIA

[Reinvented]

Put it on the nvidia controller. IMHO, it performs better than the sil.

[v0dka]

Just use RAID0 on the Nvidia and make sure you cool these puppies as well.

[Black Phoenix]

Use it as I use my Seagate: 2 in raid 0 for Windows and 2 in raid 0 for Backup...

[D_o_S]

I have an external backup disk

Running the setup SillySider posted, it rocks! For some reason, burst rate with Sil was around 100mbs, now its over 200 w00t!

[ValkyrieLenneth]

I dont think that to backup data on RAID-0 drive is a good idea...

[aug1516]

I like the Raid 0+1 idea if you can afford to lose half the space.

[butter_fry]

I have some interesting results for you that need to be taken into consideration before you make up your mind.

This is a picture comparing a 4x400gb raid0 array. They are a matched set of Western Digital RE2 sata drives.

In Red is an offboard PCI-X 133 Adaptec SATA/SAS Raid controller. Not the best, by any means, but its well built and fast. In Blue is the onboard nVraid.

That image basically speaks for itself. The nVraid controller can't handle the data. Also notice the CPU usage on the nVidia controller, that is what you're loosing to keep that stripe running even IF your board design can handle it.

Here are the same drives only with 2x400 this time.

Can't get much more identical.

YMMV, of course, but this is a dual core dual processor NF Professional based board. If anything has the bandwidth I'd guess this does.
I'm currently writing an expose` on someting we all forget to consider, the drive controller. Chipset manufactures just aren't building what we need for high load systems. With the price of GB per dollar at an all time low, many people are investing in huge ammounts of storage without taking into consideration the performance implications of all that data trying to get sucked through a straw. Gentlemen, we need fatter pipes.

-butter

[derektm]

butter,

How about 4x400 on the ULI 1575 SATA?

[butter_fry]

all my results can be found here, but read my disclaimer at the top. all the uli results are valid though.

http://www.flickerdown.com/forums/showthread.php?t=243

I'll do the 4x400 uli in a bit. i need to do a windows install on a different drive to get accurate results. And since i'm running a 2x160 raid for boot on the uli currently I can't just plug the 4x in.

[Black Phoenix]

If you say that have an external disk for backup, then stick the 4 raptor on raid 0...

[uOpt]

I have 4 WD Raptors 740GD. Now, my question is, how should I RAID them, and on which controller? I want maximum performance.

This is on a DFI Lanparty nF4 SLI DR Expert mobo.

This question is useless without telling us what exactly you want to have speed up

Onboard SATA won't give you great performance anyway.

[vitaminc]

Just do the math. That chipset has 32 PCI Express lanes.

16 lanes are used for the SLi (8x each or 16x single)
4 lanes are used for PCI-Express x4 slots (utterly dumb design decision for a useless slot)
1 lane is used for PCI-Express x4 slots (another dumb design decision for another useless slot)
8 lanes are used for chipset intercommunications

That leaves you 2-3 lanes PCI, USB, onboard sound, onboard GbE, and SATA RAID, with total bandwidth from 500MB/s to 750MB/s (250 MB/s per PCI-Express lane). GbE is 128MB/s, PCI is 33MB/s (99MB/s total), and each raptor has probably sequential read speed of 60MB/s and burst read speed of 100MB/s.

Therefore if you RAID0 4 raptors, your total available bandwidth will be eaten alive and be extremely limited and will not scale 4x. There is simply no reason to use RAID0 beyond 3 drives as your marginal performance increase becomes null. Besides, your RAID0 drive will die 4 times as early due to serial links in MTBF.

The option will be RAID 0+1 or RAID5.

It's pointless to RAID beyond 4 disks with an onboard controller (and without PCI-X 133 slots). It's like asking for professional HD audio sound quality from onboard audio or SLi 3D Gfx from onboard integrated Gfx. It ain't going to happen.

[butter_fry]

I guess maybe my screenshot of what happens to an nVraid at 4x falls on deaf eyes.
Edit: but if you've got the dough to blow, i've got a controller that can handle it.

[vitaminc]

I guess maybe my screenshot of what happens to an nVraid at 4x falls on deaf eyes.
Edit: but if you've got the dough to blow, i've got a controller that can handle it.

ooo ya
didnt see that.
a picture is worth 1000 words.

4 drive RAID0 is stupid anyway as you will at least need a dedicated PCI-X 66Mhz slot to feed the bandwidth. Most AMD overclocking motherboards suck for a decent RAID storage system.

[butter_fry]

notice the RED stripe pci-x 133 8way SAS/SATA. no problems there with the exact same drives.

[vitaminc]

notice the RED stripe pci-x 133 8way SAS/SATA. no problems there with the exact same drives.

Ya, but the thing is onboard controller will only have enough bw for 2-3 drives of mediocre performance raptors, so any RAID w/ 3 drives or below should be fine.

its about sequential/burst read/write speed and bus bandwidth. that's what sucks for AMD based deskstop/workstation motherboards; not a lot of PCI-X options available.

Or in the language of overclockers, its like putting DDR2 1000Mhz memory into a motherboard with 133Mhz FSB. It ain't gonna work.

[uOpt]

Just do the math. That chipset has 32 PCI Express lanes.

16 lanes are used for the SLi (8x each or 16x single)
4 lanes are used for PCI-Express x4 slots (utterly dumb design decision for a useless slot)
1 lane is used for PCI-Express x4 slots (another dumb design decision for another useless slot)
8 lanes are used for chipset intercommunications

That leaves you 2-3 lanes PCI, USB, onboard sound, onboard GbE, and SATA RAID, with total bandwidth from 500MB/s to 750MB/s (250 MB/s per PCI-Express lane). GbE is 128MB/s, PCI is 33MB/s (99MB/s total), and each raptor has probably sequential read speed of 60MB/s and burst read speed of 100MB/s.

Therefore if you RAID0 4 raptors, your total available bandwidth will be eaten alive and be extremely limited and will not scale 4x. There is simply no reason to use RAID0 beyond 3 drives as your marginal performance increase becomes null. Besides, your RAID0 drive will die 4 times as early due to serial links in MTBF.

The option will be RAID 0+1 or RAID5.

It's pointless to RAID beyond 4 disks with an onboard controller (and without PCI-X 133 slots). It's like asking for professional HD audio sound quality from onboard audio or SLi 3D Gfx from onboard integrated Gfx. It ain't going to happen.

Sorry your math is all wrong.

First, the SATA on the NVidia chipsets sits directly int he southbridge, I don't think it actually needs PCIe lanes.

Even then, PCIe x1 bandwidth is 500 MB/sec (byte, not bit).

That is plenty even for 4 raptors. A single lane.

Apart from that, if your applications get a speedup out of RAID-0, then 180 MB/sec are already very nice to have.

[vitaminc]

Sorry your math is all wrong.

First, the SATA on the NVidia chipsets sits directly int he southbridge, I don't think it actually needs PCIe lanes.

It doesn't "need" the PCIe lanes, but its using those bandwidth to communicate/emulate. NVDA uses 8 or 16 PCIe lanes to link the north and south bridge due to their SLi design decision/flaw.

CPU -> NB -> SB -> SATA

So your SATA bandwidth and CPU/memory load will be impacted significantly when both SLi card #2 and SATA are both sucking your bandwidth out. And the computational power limitation for NVDA's chipsets to handle all USB, SLi, SATA, PCI, and PCIe traffic routing all at the same time.

There is a good reason why Nvidia SLi/gaming chipsets are rarely used in storage systems and are getting designed out by Braodcom.

I will go dig up some schematics. But both Nvidia's nForce4 SLi and SLi16 chipsets are not really designed for workstation level storage systems.

Even then, PCIe x1 bandwidth is 500 MB/sec (byte, not bit).

http://en.wikipedia.org/wiki/List_of....28internal.29

Looks like 250MB/s to me. I don't feel like arguing against Wikipedia. Even if you convert 2500Mb/s into MB/s, its still only 312.5MB/s, not even enough for Ultra320/FC.

Apart from that, if your applications get a speedup out of RAID-0, then 180 MB/sec are already very nice to have.

Uh, 180MB/sec STR? That's quite impossible with Raptors with Nvidia's SoC SATA. You cannot expect STR to add up. i.e. 4 HDD with STR of 60MB/s in RAID0 will not add up to 240MB/s.

[butter_fry]

That is plenty even for 4 raptors. A single lane.

Apart from that, if your applications get a speedup out of RAID-0, then 180 MB/sec are already very nice to have.

*sigh* again it looks like my screenshot has been ignored.
uOpt, I showed you what happens when you put 4x raid0 on the nvidia chipset.

[derektm]

http://en.wikipedia.org/wiki/List_of....28internal.29

Looks like 250MB/s to me. I don't feel like arguing against Wikipedia. Even if you convert 2500Mb/s into MB/s, its still only 312.5MB/s, not even enough for Ultra320/FC.

The PCI Express bus is bidirectional, therefore its 500MB/s total

[vitaminc]

*sigh* again it looks like my screenshot has been ignored.
uOpt, I showed you what happens when you put 4x raid0 on the nvidia chipset.

And they willl probbaly choose to believe 4xRAID0 raptors will yield better results because, uh, your test is not using Raptors (judging from the name and the random access time).

RAID0 beyond 2 drives is simply retarded and doesnt yield any significant performance gains.

If you want a fast drive, ditch the kiddy Raptors and pick up Cheetah 15k.4 (or 15k.5 with STR higher than 100MB/s and 3.2sec RAT). U320 15k RPM SCSI drives will still outperform SATA2 drives by a good margin in all tests.

The PCI Express bus is bidirectional, therefore its 500MB/s total

That is correct. However, it IS directional, so your STR (which is upstream) will still be capped at 1 direction * 2.5Gb/s/direction = 2.5Gb/s excluding the packet overheads.

[uOpt]

Uh, 180MB/sec STR? That's quite impossible with Raptors with Nvidia's SoC SATA. You cannot expect STR to add up. i.e. 4 HDD with STR of 60MB/s in RAID0 will not add up to 240MB/s.

See here:
http://cracauer-forum.cons.org/forum/raid.html

Pure software raid-0 on three 7200.8 on NVidia NForce SLI gives:

• 182.59 MB/s (191457784 B/s) (43.8% CPU, 4267.8 KB/sec/CPU) write
• 159.23 MB/s (166967535 B/s) (43.1% CPU, 3779.7 KB/sec/CPU) read

That is total, average speed of reading/writing a 16 GB file in 8 KB blocks using a machine with 512 MB RAM.

To tip it off, you can look for the number of delivering this over NVidia's GbE at the same time.

[nn_step]

*sigh* again it looks like my screenshot has been ignored.
uOpt, I showed you what happens when you put 4x raid0 on the nvidia chipset.

Don't argue about raid with uOpt.. he is always right..(atleast when it comes to raid1, Raid0 and onboard raid)

[Shark-357]

Just got WD 320GB Sata2 16mb for storage so i used my old 2x120gb Hitachi sata for raid0 this is what i got with it.