Re: [gentoo-user] 1-Terabyte drives - 4K sector sizes? -> bar performance so far

[J. Roeleveld]

On Monday 08 February 2010 21:34:01 Paul Hartman wrote:
> On Mon, Feb 8, 2010 at 12:52 PM, Valmor de Almeida <val.gentoo@×××××.com>
wrote:
> > Mark Knecht wrote:
> > [snip]
> >
> >>    This has been helpful for me. I'm glad Valmor is getting better
> >> results also.
> >
> > [snip]
> >
> > These 4k-sector drives can be problematic when upgrading older
> > computers. For instance, my laptop BIOS would not boot from the toshiba
> > drive I mentioned earlier. However when used as an external usb drive, I
> > could boot gentoo. Since I have been using this drive as backup storage
> > I did not investigate the reason for the lower speed. I am happy to get
> > a factor of 8 in speed up now after you did the research :)
> >
> > Thanks for your postings.
>
> Thanks for the info everyone, but do you understand the agony I am now
> suffering at the fact that all disk in my system (including all parts
> of my RAID5) are starting on sector 63 and I don't have sufficient
> free space (or free time) to repartition them? :) I am really curious
> if there are any gains to be made on my own system...
>
> Next time I partition I will definitely pay attention to this, and
> feel foolish that I didn't pay attention before. Thanks.
>

I have similar disks in my new system and was lucky that I was still in the 
testing phase and hadn't filled the disks yet.
After changing the partitions to start at sector 64, the creation of the 
RAID-5 set went from around 22 hours to 9 hours.

I also get a much higher throughput (in the range of at least 4 times faster), 
so I would recommend doing the change if you can.

I now only need to figure out the best way to configure LVM over this to get 
the best performance from it. Does anyone know of a decent way of figuring 
this out?
I got 6 disks in Raid-5.

Thanks,

Joost Roeleveld