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FC60 and volume groups

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Jan den Rooijen
Occasional Visitor

FC60 and volume groups

We have ordered a FC60 with 6 sc10's, each with 4 18Gb-disks.
According to a note in the FC60 Advanced User Guide, LVM will override the ownership.

For example (all from the manual, FC60 is not installed yet):
Create 2 RAID 0/1 LUN's:
amcfg -L A:0 -d 1:0,2:0,3:0,4:0,5:0,6:0 -r 10 -S
amcfg -L B:1 -d 1:8,2:8,3:8,4:8,5:8,6:8 -r 10 -S
Ioscan will show 4 device files:
/dev/dsk/c4t0d0 (LUN0, controller A)
/dev/dsk/c4t0d1 (LUN1, controller A)
/dev/dsk/c5t0d0 (LUN0, controller B)
/dev/dsk/c5t0d1 (LUN1, controller B)

Q1) How to create volume groups with LVM:
A) use primary path (what happens if controller A fails, will vg04 automatically change to controller B?):
vgcreate /dev/vg04 /dev/dsk/c4t0d0
vgcreate /dev/vg05 /dev/dsk/c5t0d1
B) both primary and alternate paths (is this necessary in case of a controller failure?):
vgcreate /dev/vg04 /dev/dsk/c4t0d0 /dev/dsk/c5t0d0
vgcreate /dev/vg05 /dev/dsk/c5t0d1 /dev/dsk/c4t0d1

Q2) Can you change the ownership for LUN1 afterwards (or will LVM still overrule this?):
vgcreate /dev/vg04 /dev/dsk/c4t0d0
vgcreate /dev/vg05 /dev/dsk/c4t0d1
amcfg -M 1 -C B

Insu Kim
Honored Contributor

Re: FC60 and volume groups

For Q1) answer is B
For Q2,
Yes, You can change the ownership of a bound LUN without unbining and binding LUN again.
This can be done if you'd like to share load between controllers.

Best regards,
Never say "no" first.
Alexander M. Ermes
Honored Contributor

Re: FC60 and volume groups

Hi there.
Answer B is the way to go.
In case of a failure access goes through controler B, second you can share the load between the two controlers.
If you need mire info about this, just contact me ( ger7axe@europe.ups.com ).
Alexander M. Ermes
.. and all these memories are going to vanish like tears in the rain! final words from Rutger Hauer in "Blade Runner"