[pve-devel] new cache benchmark results

[Alexandre DERUMIER]

>>I doubt the a file system can influence the sector size of the drive firmware. 

For me, If the filesystem is misaligned, you'll write 2 sector instead of one, so you'll have a performance degradation.




AFAIK, rhel5,debian squeeze,windows xp don't align good by default their partition. (on the 63th sector)

since fdisk 2.17, first partition is aligned to 2,048 sector. (which is best for ssd)
http://www.thomas-krenn.com/en/wiki/Partition_Alignment

I don't know how it's works when lvm is used.

(BTW: Maybe we need to check if default proxmox setup is correctly aligned)

----- Mail original ----- 

De: "Dietmar Maurer" <dietmar at proxmox.com> 
À: "Michael Rasmussen" <mir at datanom.net>, pve-devel at pve.proxmox.com 
Envoyé: Samedi 10 Novembre 2012 15:53:12 
Objet: Re: [pve-devel] new cache benchmark results 

> > They use 4K internally, but emulates 512 bytes sectors (512e mode) 
> > 
> > Do you have any evidence that those drives run in 4Kn mode? 
> > 
> If I have understand this forum post correct 
> (http://forum.hddguru.com/sector-formatting-what-you-need-know- 
> t15827.html) 
> it all depends whether the filesystem is 4k aligned or not. If the first sector, 
> after the MBR, begins on a 4K boundary the drives firmware will 
> automatically activate 4K mode. 

I doubt the a file system can influence the sector size of the drive firmware. 
Do you own such drive, or do you guess? 

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