topic Re: system hanging while creating a vg in Operating System - HP-UX

system hanging while creating a vg

n00body — Sun, 13 Jan 2008 08:16:49 GMT

Guys , I'm having some problem here with creating the vg . everytimes when i created a vg , its seems to be hung while i run the vgcreate .

# vgcreate /dev/vg01 /dev/dsk/c2t1d0
Increased the number of physical extents per physical volume to 35003.

What i did was , run pvcreate -f , then make directory /dev/vg01 , then mknod /dev/vg01/group c 64 0x030000 . And then after that I will run the vgcreate . Is there any steps missing ? Thanks .

Re: system hanging while creating a vg

VK2COT — Sun, 13 Jan 2008 09:21:53 GMT

Hello,

Are you, by any chance, running HP-UX 11.23?
This was documented in the past.

Basically, the VGRA (volume group reserved
area, an area of data defining the layout of
the VG and replicated across all physical
volumes in the VG) must fit within a single
LVM logical (and physical) extent.

You have not specified an extent size, so
LVM will default to 4 MB. If the VGRA needed
to satisfy the size of disk you are dealing
with exceeds this size, you will experience
a hung vgcreate session with HP-UX 11.23.

Prior to 11.23, the vgcreate command would
simply have failed with an error suggesting
insufficient space.

I believe there are patches to fix this problem. So, you could either decide
to patch your server or use workaround:
increase the size of the extent space.

LVM already granted a "Max PE per PV" of
35003 at 4 MB. Try the following commands:

# pvcreate -f /dev/rdsk/c2t1d0
# mkdir /dev/vg01
# mknod /dev/vg01/group c 64 0x030000
# vgcreate -s 8 -e XXX /dev/vg01 /dev/dsk/c2t1d0

Use "-e XXX" to define number of available extents on the disk. For example,
140 GB disk would have around 17501 extents
of size 8 MB.

I often use even larger extents - 16 and 32 MB.

This will set up your VG with an extend size of 8 MB, which should be enough to cope with
the size of your disk. If not, try 16 MB with the max PEs reduced accordingly:

# vgcreate -s 16 -e 8750 /dev/vg01 /dev/dsk/c2t1d0

Cheers,

VK2COT

Re: system hanging while creating a vg

n00body — Sun, 13 Jan 2008 09:57:25 GMT

dude .. seems that vgcreate is not hanging now .. Thanks a lot pals ..

# vgcreate -s 16 -e 8750 /dev/vg01 /dev/dsk/c2t1d0
Volume group "/dev/vg01" has been successfully created.
Volume Group configuration for /dev/vg01 has been saved in /etc/lvmconf/vg01.conf
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