Antw: Re: MBR partitions slow?

From: Ulrich Windl
Date: Thu Sep 01 2016 - 02:30:57 EST


>>> Mark D Rustad <mrustad@xxxxxxxxx> schrieb am 31.08.2016 um 17:32 in Nachricht
<E2D72371-913B-4460-A370-C141835AD919@xxxxxxxxx>:
> Ulrich Windl <Ulrich.Windl@xxxxxxxxxxxxxxxxxxxx> wrote:
>
>> So without partition the throughput is about twice as high! Why?
>
> My first thought is that by starting at block 0 the accesses were aligned
> with the flash block size of the device. By starting at a partition, the
> accesses probably were not so aligned.

Hi!

Thanks for answering. Yes, you are right: Usually I use fdisk to create partitions, and the tool does proper aligning for the partitions. In my case YaST insisted on having a partition before creating a filesystem, so I created on within YaST, and that partition turned out to be badly aligned (I think Yast uses cfdisk internally). I'm sorry that I didn't think about that earlier!

Stracing fdisk, I also learned about ioctl(BLKIOOPT) and related...

Regards,
Ulrich

>
> --
> Mark Rustad, MRustad@xxxxxxxxx