serious problem with raid 0

[scyphe]

Is it possible to use two SATA-disks of different brands (but same exact size) in RAID? From what I understand, pretty much any combination is attainable, just wanted to check here before doing something stupid.

 

As in my sig, I'd like to RAID SATA1 & SATA4. Is it possible without having them on the same controller? Perhaps it's even better, no overhead in the chip and lanes.

[learners permit]

I think it would be possible if the seek read and write speed and latencies were identical.

[scyphe]

Moved the seagate 250 & western digital 250 to the nvidia sata (sata 3 & 4), and after messing about, I got it working just fine. 106mb/s according to speed test in nero, 83mb/s drive index according to sisoft sandra 2005 r3.

[ukasz]

ok i,ve installed windows with integrated drivers and it is working but still big jumps

 

look:

http://members.lycos.co.uk/ukasz20/hdtach.jpg

[ukasz]

when i am copying something from partition to partiton speed is 40 mb/sec on my raid array

 

in single ide drive i had 50 mb/sec prtition to partiton (wd)

 

both tests on total commander

 

there is another driver for scsi & raid controllers (vax3475scsi controller) is it normal ?

 

now i am really hopeless

[ukasz]

in first few seconds it is 40 than it drops to 14 mb/ sec

 

what the f**k is going on

[wevsspot]

Go here and download Samsung's Hard Disk Utility;

 

http://product.samsung.com/cgi-bin/nabc/su...uct_results.jsp

 

Run all diagnostics to ensure that both drives are functioning correctly.

 

Disable any power management or acoustic management features via the utility.

 

Reboot and re-run your benchmarks after performing the two above steps.

[learners permit]

Just a guess but have you tried monitoring the power supply rails with an accurate voltmeter?

[Guest mofunk]

I am new to most of this so please forgive me, but I take it this is bad because of the decline? Meaning that at 20,1GB you are at 110GB/s and at 160,1GB you are at 60MB/s is a bad thing, it should be more constant.

 

Well I have my drives in raid 0 and have the same issue. Doig the long bench I start at 130GB/s then at 600,1GB I get 60MB/s. My drives are in my sig.

[wevsspot]

You know Learners Permit, that may be one of the wisest things I've seen in this thread. I completely skipped over the fact that he is running a 410W psu.

 

UKASZ, you should definitely check your power rails under load (during file transfer). According to the spec. sheet on Samsung's website each of your hard drives by themselves draw from 8.8-9.0W of power under load. So figure worst case 9WX2 = 18W of power required for your hard drives alone.

 

Also, need to know what utility you are using to measure your disk transfer speeds. And you really should update your sig. to include what video card you are using and if you have any additional disk drives (like DVD or CRROM, fans etc.) running on your system. Then we could calculate a voltage draw.

[wevsspot]

EDIT: Ok UKASZ, I went back and read the entire thread and found that you are using a program called Total Commander. I'm not familiar with that program whatsoever, so I can't really comment on your results.

 

MOFUNK, are you running a disk read benchmark using HDTach? That isn't the same thing as UKASZ is asking about. He is talking specifically disk to disk transfer speeds. It is a result of physics that your disk read and write speeds drop off through the course of the test. The outer part of your hard disk is capable of holding more data than the inner portions due to the size of the platter. Just look at a hard drive disk and you will see that the total storage space near the center of the disk is very small compared to the storage space at the outer edges of your disk. Also, as your read and write heads access the disk, the rotational speeds of the disk are different at the outer edges of your disk than the center or inner portions of your disk. There is a mathmatical formula for this.

[wevsspot]

I wouldn't be too worried about the spikes. As an example here are 2 WD 74GB Raptors in Raid0