Extent size changing on ignite load...Extents doubled with change in drive size on target servers

[Craig A. Sharp]

I have an ignite golden image that I am using to load servers. The VG extent size is set for 16 M on the image. The servers that I am loading have 73 Gig drives in them. I had to use the image to load a server that has 144 Gig drives and without changing anything, just loading, the extent size changed to 32 M. Is this the expected action from Ignite? Will it update the extent size based on drive size in the target server?

Thanks!

[Tim Nelson]

I believe so. It is more of an ignite install thing rather than an ignite image thing.

I have servers configured the same way. Different pe_size based on total size of disk.

Same happens with cold install.

I never had reason to worry about it. Although 16M pe_size is adeqauate to store the LVM meta data for a 146GB drive, ignite itself may have some better/different rule.

[James R. Ferguson]

Hi Craig:

This is expected when your apply an Ignite image taken from a smaller physical drive to a larger one. The extent size is adjusted upwards to accomodate the number of disk extents so that the whole disk can be utilized. This is not an issue.

Regards!

...JRF...

[Pete Randall]

LVM by default adjusts the extent size so that the MaxPE per volume can accomodate the larger drives.


Pete

[Bill Hassell]

Actually, this is a vgcreate feature rather than Ignite. When Ignite runs vgcreate to create the new volume group, vgcreate adjusts the extent size to match the disk(s) being used. A larger extent size means that you may be able to add more disks to the VG in the future. This is a common mistake when configuring a growing server (extent size too small). Generally, when you underestimate the extent size for a growing VG, you may have to backup everything on the VG, remove it and recreate it correctly and reload. The exception is 11.31 where the vgmodify command is available.

[James R. Ferguson]

Hi Craig:

> Bill: The exception is 11.31 where the vgmodify command is available.

The 'vgmodify' command has also been back-ported to 11.23 with patch PHCO_36744 and its dependencies.

Regards!

...JRF...