[linux-lvm] Paralell IO performance with LVM and XFS

[Miguel Angel de Vega]

Hi!

I've a Dual P2 450 with a Disk Array with 4 scsi disks with XFS.
With one single disc I've 10 Mb/s reading and writing, so I think that if I 
stripe all disc of the array, it can give me 4x10Mb = 40Mb/s more or less, 
but I only gets 10 Mg/s!!  
These disks usually gives up to 30 Mg/s in SGI machines and other single scsi 
disks in the Dual P2 (with the same controller and XFS) gives 20Mg/s, so i 
think that the problem must be LVM (the options maybe??? bad stripped 
options??). 

I show how mount all the Logical Volumen:

partionated all discs like 8e
#pvcreate /dev/sda1 ...
#vgcreate test /dev/sda1 /dev/sdb1 /dev/sdc1 /dev/sdd1
#lvcreate -n stripped -i 4 -I 64 test -L 30000M
(I tryed with -I 128, 256 and 512 but not big differences)

#mkfs -t xfs /dev/test/stripped  (only supports 4kb of block size)

what can be the problem??
thanks

Miguel Angel de Vega fernandez
SGO
Madrid - Spain