Hi Erwan, I do not use partitions on the drives so the whole disk /dev/sdb is used as md component device, i was in the understanding that if not using partitions the alignment is correct or am i wrong? Kind regards, Caspar Smit Op 12 maart 2012 13:57 heeft Erwan MAS <erwan@xxxxxxxxxx> het volgende geschreven: > On Mon, Mar 12, 2012 at 01:34:08PM +0100, Caspar Smit wrote: >> Hi all, >> >> I don't know exactly which mailinglists to use for this one so I hope >> i used the right ones. >> >> I did some performance testing on a new system and found out some >> things I couldn't explain or didn't expect. >> At the end are some questions I hope to get answered to explain the >> tings i'm seeing in the test. >> >> First of all a description of my setup. >> >> The server is a 36 bay 3,5" supermicro chassis filled with 36x 2TB >> SATA 7200 RPM disks. >> [../..] > > Please check alignement of each level of stockage . > Because this disk present to controller a block size of 512 bytes , but internal > use a 4k block size . > > You must check that alignement is correct for : > disk partionnemnt > md device > pv lvm > > -- > ____________________________________________________________ > / Erwan MAS /\ > | mailto:erwan@xxxxxxxxxx |_/ > ___|________________________________________________________ | > \___________________________________________________________\__/ -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html