Matrix Raid - Oh Yeah

[virtualrain]

About time someone posted a graph comparing the two and performance is unchanged, just as expected.

The transfer rate is unaffected, but the access times on the smaller (faster) partition are signficantly improved because the heads need to traverse less of the platter to access data.

[epion2985]

These numbers just frankly don't make sense. I am referring mainly to the burst speed here.

Why? Well, lets assume you are using 4x full-speed SATA II ports here, for a total bit rate of 12Gbps, or 1.5GBps. Yet your burst speeds are showing in excess of 3GBps! That's over *twice* the maximum, theoretical bandwidth (which you will never hit).

Clearly there's something else going on here. You said you set this up in Windows... I'm almost wondering if the burst speed is coming from caching data to RAM, because it's *not* coming from your hard drives.

With that said, the rest also comes under suspicion...

I'm surprised you didn't notice that your burst numbers - being more than 10x what you should see with one drive - were at least somewhat suspicious.

His numbers are bogus and this has been discussed before here. The above mentioned benchmarks do not reflect real life performance due to different read patterns etc, and matrix raid seems to really throw things off in them. Really hd benchmarks are useless for the most part. Test on real applications as thats the only valid result data.

[tuskenraider]

The transfer rate is unaffected, but the access times on the smaller (faster) partition are signficantly improved because the heads need to traverse less of the platter to access data.

Well for benchmarking yes, but if you put the same amount of data on either setup and at least defragment them, both setups will have about the same access speed to get to said data. 15GB of data on a 20GB or 200GB partition is still 15GB. Yes, if you didn't defragment the drive, the data will be more scattered across the platter, but who is a PC geek that doesn't do such a thing, let alone have a better third party defragmenter.

[Supershanks]

@epion2985

His numbers are bogus and this has been discussed before here

u mean i just invented them or are u talking about the burst rates, which we have already shown is down to the write back cache.

[EsaT]

Matrix RAID uses RAM as cache so that's from where high burst speeds come.

Only speed benefit from Matrix RAID1 (vs. normal RAID1) comes from effective shortstroking which lowers random access time.

What i see as a benefit of matrix is the abilility to have a 2nd raid slice with a different Raid 1,5 tec., to get the best options whilst gaining the benefit of the max number of drives.

I think you wouldn't want to use software (maybe better word would be "non-hardware") RAID5 for anything else than read...
http://techreport.com/reviews/2005q4...d/index.x?pg=7


As for synthetic benchmarks... those are useless for knowing real performance:
Theoretically RAID5 increases write speed much over single disk (because of striping) but in reality even hardware controllers struggle to rise real write speed above single disk and in case of smaller files it's actually slower.

[Supershanks]

Interesting linksw EsaT thanks

[virtualrain]

Only speed benefit ... comes from effective shortstroking

If I could only convince my girlfriend of this! (sorry, couldn't resist!)

[Richard Dower]

Thanks!...i installed the Intel Matrix Storage Manager (software),enabled write back cache and got a speed bump!
See specs for RAID setup, i didn't create two RAID partitions as per the nature of this thread...i wanted to see if my normal RAID array would benefit from enabling write back cache, and it did.

I went from 140MB/s to 152MB/s average read speed with write back enabled. I don't have two RAID arrays setup...a single one, but i have partioned the single RAID array during Vista setup. C drive has 120GB while D has 18.5GB.

[Jodiuh]

Here's the HD Tach from an Intel Bad Axe 2 (ICH7R) using half the total size of 2 ADFD 74 Giggers w/ a 64K strip size and write back cache enabled.

[Richard Dower]

So you're only using 69.2GB of the full 138.5GB?
I guess the increased speed bump must be you're using the fastest part of the HDD's.

[Jodiuh]

Yeah, I use the other half in a mirror for stuff.

[Aceit]

would it be possible with 2x 36 gbs raptors hd? I would like to make a first partition fast ( raid0) to boot up the OS and the rest of the raid , another RAID0 with all the rest of data.
I also have a seagate 320 gbs for backups and data, what should i do?

[RealTelstar]

would it be possible with 2x 36 gbs raptors hd? I would like to make a first partition fast ( raid0) to boot up the OS and the rest of the raid , another RAID0 with all the rest of data.

Yes, if you have a motherboard with an intel southbridge capable of Matrix raid (ICH7R or ICH8R).

I also have a seagate 320 gbs for backups and data, what should i do?

I would make the first partition for swap and temporaries, then all the rest for data ad backups.