[RE] Poorer performance with Raid0 then without?

Hadders ata.raid at workingwithit.com
Tue Jan 2 02:01:29 UTC 2007


Hi, just to jump in.

/dev/md is software RAID, turn off the RAID feature on the hardware in 
the BIOS (you'll need to reinstall)
/dev/mapper is done with dmraid that accesses the RAID container setup 
by your hardware device.

I might add too that when I've done RAID with PATA or SATA One (I) disks 
in the past, the performance for RAID 0 wasn't that great. To get 
excellent performance, use SATA two (II) disks with NCQ support.

At the moment, I'm using Intel SATA II RAID 0 (dev/mapper) and the only 
problems I had was
i) my dmraid needed to be rc11 or greater
ii) container initialization was not present in the initrd after kernal 
upgrades
iii) the initialization command needed adjusting (thanks to James Olsen)

This lets me dual boot the container between Windows and Linux.  If you 
don't need dual boot, go Linux Software RAID.

H

Listbox wrote:
> Yeah, that's what I did that I described as
> "I tried removing the third drive on the board (primary slave), no 
> effect. "
> This smells like a driver/software problem. I'd like to try a 
> different setup.
> Is there some way to use "md type" RAID that uses /dev/md? instead of 
> "dm type" RAID that uses /dev/mapper/*?
>  
> Thanks!
>  
> Listbox
> ------------------------------------------------------------------------
> **




More information about the Ataraid-list mailing list