PE Size => Performance

[JesusSantiago]

I have a Integrity server rx2660 with 4 x 147G B internal disk on RAID5 over a P400 SmartArray controller.

HP-UX 11.31 Operating system and a total capacity of RAID5 of 430GB.

I created one VG of 430Gb but HP-UX bound the PE size to 128MB.

Could Somebody tell me if:

1.- PE size of 128MB might cause performance delay?

2.- PE size of 128MB allow the server to use 100% of disk space?


I´m attach exit of vgdisplay

# vgdisplay vg03

--- Volume groups ---

VG Name /dev/vg03

VG Write Access read/write

VG Status available

Max LV 255

Cur LV 0

Open LV 0

Max PV 16

Cur PV 1

Act PV 1

Max PE per PV 3280

VGDA 2

PE Size (Mbytes) 128

Total PE 3280

Alloc PE 0

Free PE 3280

Total PVG 0

Total Spare PVs 0

Total Spare PVs in use 0

VG Version 1.0.0

[Jeeshan]

Hi

The only downside of using such a large PE size is that you could leave a rather large chunk usused

[James R. Ferguson]

Hi:

You can either recreate your volume group with a larger value for 'max_pe' or use 'vgmodify' to change it. This will allow you to fully utilize all available disk extents.

Regards!

...JRF...

[Bill Hassell]

The PE size is only used for bookeeping, and has nothing to do with actual read or write performance. The PE=128 means that the smallest lvol is 1 PE or 128 MB. You can't create a 200 MB lvol as it have to be 2 PE's or 256 MB. Of course, with a 400+ GB volume group, this is a non-issue.