Veritas Volume manager encapsulation
 

Hi, all

I have one problem about vxvm disk encapsulation.

# uname -a
SunOS SB100 5.10 Generic_120011-14 sun4u sparc SUNW,Sun-Blade-100

I have used all 6 slices except slice 2 which indicates whole disk. I installed veritas storage foundation 5.0 then used its veritas volume
manager5.0 to encapsulate the root disk.

vxdiskadm -> Select option 2(Encapsulate disk)

After encapsulation and reboot, I found slice 3,4,5 got lost. I checked
veritas volume manager5.0 admin document, encapsulation needs the two free partition on the encapsulation needed disk. I dumpedmy disk label
for my root disk. We can see slice 3,4,5 got lost. slice6 is pub region
of vxvm and slice7 is private region of vxvm. Can someone tell me why
encapsulation caused my slisces data loss because encapsulation should
reserve all data on disk.


partition> p
Volume: SB100-Vo
Current partition table (original):
Total disk cylinders available: 38307 + 2 (reserved cylinders)

Part Tag Flag Cylinders Size Blocks
0 root wm 18 - 7547 14.65GB (7530/0/0) 30722400
1 swap wu 7548 - 8300 1.46GB (753/0/0) 3072240
2 backup wm 0 - 38306 74.53GB (38307/0/0) 156292560
3 unassigned wm 0 0 (76/0/0) 310080 <<<===*****
4 unassigned wm 0 0 (29299/0/0) 119539920 <<===*****
5 unassigned wm 0 0 (631/0/0) 2574480 <<===*****
6 - wu 18 - 38306 74.49GB (38289/0/0) 156219120
7 - wu 0 - 17 35.86MB (18/0/0) 7344

veritas volume manager does change the vtoc when you encapsulate the boot disk. Every version, every type. Solaris volume manager does not.

Just because your partition table changed, it does not mean that the data is lost.

However, you are right regarding the need of two free slices for encapsulation.

Hi, javier.e.menendez

How VXVM changed VTOC, what is its policy?

The rules for encapsulation are simple. You need 2 free cylinders and two unassigned slices (0 cyls in size). The two free
cylinders are taken from swap if needed so that is not a problem. The two unassigned slices are non negotiable. Your original
vtoc and /etc/vfstab are saved on your system so they can be put back if needed when you run vxunroot and unencapsulate the disk if you want to.

That is why a lot of people prefer svm for the boot disk (it does not change the vtoc). If needed, you can boot cdrom -s, replace /etc/vfstab with the original, uncomment the last line of /etc/system, reboot and you are back up and running. Can't do that with vxvm since your vtoc does NOT point to your original locations. The manual unencapsulation is more of a pain.

Hope it helps,

J.

What is disk encapsulate actually? Why we need disk encapsulate?