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AIX 4.3.2 rootvg chvg

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Deak

Technical User
Nov 9, 2001
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OK So I have AIX 4.3.2 currantly on my system. I want to upgrade but have no space to do this. I have a New 9GB drive I just added to the system. I want to get rootvg from my currant 1GB drive to my new 9GB drive. I dont want to extend vg across multiple drives. I would like to totally move it to its own drive. I believe it is possible to mirror it I have to use the chvg -t option but I dont understand how I come up with the number I use with this option. Can anyone help with this?
 
Hi,

if you use the default, the volume group can address 1016 PPs per disk and 32 disks for standard volume groups. The 1016 comes from 2^10-8 (addressable space by 10 bits minus 8 PPs for realocation) The 32 is 2^5 (adressable space by 5 bits). There is one bit left from the total number of the 16 bits (1 word) - that is reserved.

If you increase the maximum number of PPs per disk then you have to decrease the maximum number of disks in the volume group. This change of the ratio of the maximum PPs : maximum disks is the factor. See the example:
Factor: MaxPP/disk MaxDisk/VG
1 1016 32 = No factor
2 2040 16
4 4088 8
8 8184 4
16 16376 2 - I would be afraid to use this as the MaxDisk/VG reduces to 2.

See also the PP SIZE parameter as the "PP SIZE" * "MaxPP/disk" = "MaxDiskSize"
The "MaxDiskSize" * "MaxDisk/VG" = "MaxSizeOfVG"

The behaviour is for the standard volume groups. There are also so called big volume groups where the behaviour is similar, but not the same.
 
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