Re: PROBLEM: I/O scheduler problem with an 8 SATA disks raid 5 under heavy load ?

[Guillaume Laurès]

Hello all,

A bit of update to this issue.

Switching the cabling of the most problematic drive with a new one  
didn't fix the issue.
I couldn't yet switch the power supply with a more powerful one.  
However I temporarily added a pci-e SATA host and another drive, the  
situation was just as bad, not worse ;-) This HBA just had 2 ports,  
so I couldn't swap it completely with the nvidia ports.

Just as a guess I added sata_nv.adma=0 and the problem completly  
disappeared for 4 weeks now. Removing it from cmdline just make it  
come back.

Unfortunately I'm running xen on this host so I don't think adma  
patches if any may be suitable to me, at least as long as something >  
2.6.20 doesn't come in gentoo for xen...

Regards,

GoM

Le 9 janv. 08 à 01:00, Robert Hancock a écrit :

> > So it seems to be either a cabling problem or a bug with sata_nv ?  
> > I'm running gentoo's 2.6.20-xen, and maybe my problem looks like  
> > the sata_nv/adma/samsung problems reports I can see on the net ?
>
> I don't think it's the same problem. In that case the controller  
> appears to indicate that it didn't even start processing the  
> command. In this case it's indicating that the command was sent to  
> the drive and is still waiting for it to indicate completion.
>
> It could be a cabling problem, yes. Also, are you sure your power  
> supply is able to handle the power draw of that many drives?

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