MAX PE PER PV

[Indrajit Bhagat]

Hi There I am having an VG with MAX PV where i trying to increase the MAX PE per Pv to 65535 , but it is giving some limitation. I am confused in the realation of MAX PV/PAX PE PER PV & PE Size

abcd:/tmp#vgdisplay /dev/vgdrt01_1
--- Volume groups ---
VG Name                     /dev/vgdrt01_1
VG Write Access             read/write     
VG Status                   available                 
Max LV                      255    
Cur LV                      0      
Open LV                     0      
Max PV                      255    
Cur PV                      40     
Act PV                      40     
Max PE per PV               1016         
VGDA                        80  
PE Size (Mbytes)            32              
Total PE                    22280   
Alloc PE                    0       
Free PE                     22280   
Total PVG                   10       
Total Spare PVs             0              
Total Spare PVs in use      0  

anlbiluh:/tmp#vgchange -a n /dev/vgdrt01_1
Volume group "/dev/vgdrt01_1" has been successfully changed.

vgmodify -e 65535 /dev/vgdrt01_1
abcd:/tmp#vgmodify -e 65535 /dev/vgdrt01_1

Current Volume Group settings:
                                          Max LV      255
                                          Max PV      255
                                   Max PE per PV     1016
                                PE Size (Mbytes)       32
                              VGRA Size (Kbytes)     2144
vgmodify: VGRA for the disk is too big for the specified
parameters. Decrease max_PVs and/or max_PEs.

vgchange -a y /dev/vgdrt01_1

could some let me know the relation between : MAX PV & MAX PE PER PV & PE Size

[Torsten.]

LVM needs space in the VGRA (at the beginning of the disk) to maintain the data map. If you reserve too much PVs or PEs per PV there is not enough space to hold the values.

You should decrease the maximums to a realistic value.

(please calculate your 255 max PVs, the max PE and the PE size!)

[Indrajit Bhagat]

Hi Torsten

I appreciate if could ellaborate it.

[Torsten.]

You are going to reserve 65535 entries per PV for 255 PVs - this is just too much, you don't have enough space in VGRA to hold all these entries (and I'm sure you will never need so much).

The LVM admin guide have a detailed explanation about this.