Unable to create volume group

[Keith Winger]

I am trying to create a volume group using luns from an EMC clarion CX3-20 and am getting the following error message.

[root@shlodb01 /]# vgcreate -p 8 /dev/vgname /dev/disk/disk16
Increased the number of physical extents per physical volume to 3839.
vgcreate: Volume group "/dev/vgname" could not be created:
Unable to read the physical volume.


I get the following message when I use dd to write to the device file.

[root@shlodb01 /]# dd if=/dev/disk/disk16 of=/dev/null count=1 seek=8 bs=1024
1+0 records in
1+0 records out
[root@shlodb01 /]# dd of=/dev/disk/disk16 if=/dev/null count=1 seek=8 bs=1024
0+0 records in
0+0 records out


diskinfo returns this

[root@shlodb01 /]# diskinfo -v /dev/rdisk/disk16
SCSI describe of /dev/rdisk/disk16:
vendor: DGC
product id: CX3-20fWDR5
type: direct access
size: 15728640 Kbytes
bytes per sector: 512
rev level: HP03
blocks per disk: 31457280
ISO version: 0
ECMA version: 0
ANSI version: 4
removable media: no
response format: 2
(Additional inquiry bytes: (32)68 (33)32 (34)20 (35)43 (36)4f (37)4e (38)54 (39)52 (40)4f (41)4c (42)4c (43)45 (44)52 (45)20 (46)30 (47)30 (48)30 (49)20 (50)20 (51)0 (52)0 (53)0 (54)3c (55)2 (56)60 (57)1 (58)9c (59)8 (60)c0 (61)13 (62)40 (63)0 (64)0 (65)0 (66)0 (67)0 (68)0 (69)0 (70)0 (71)0 (72)0 (73)0 (74)0 (75)0 (76)0 (77)0 (78)0 (79)0 (80)0 (81)0 (82)0 (83)0 (84)0 (85)0 (86)0 (87)0 (88)0 (89)0 (90)0 (91)2 (92)1 (93)0 (94)0 (95)31 (96)39 (97)30 (98)31 (99)31 (100)30 (101)30 (102)30 (103)39 (104)36 (105)0 (106)0 (107)0 (108)1f (109)30 (110)8f (111)0 (112)1f (113)30 (114)bf (115)0 (116)0 (117)0 (118)0 (119)0 (120)0 (121)0 (122)0 )


According to the documentation I needed to make sure that the EMC LUN is configured to allow write cache. This has been done.

What am I missing? What else do I need to check?

Thanks,
I will award points.
Keith

[Keith Winger]

I am using HP-UX 11.31.

[Analyst]

Hi Keith,

what is the output of pvcreate dev/disk/disk16, and pvcreate -f dev/disk/disk16.

Whether the pv is created without any errors.

The dd output gives confirmed result that , the disk is fine.

>According to the documentation I needed to make sure that the EMC LUN is configured to allow write cache. This has been done

better to confirm that.

Thanks,
Analyst.

[Keith Winger]

I had one of my dd command wrong. This one is returning an error.

[root@shlodb01 /]# dd if=/dev/disk/disk16 of=/dev/null count=1 seek=8 bs=102
dd read error: I/O error
0+0 records in
0+0 records out


pvcreate works fine.
[root@shlodb01 /]# pvcreate /dev/rdisk/disk16
Physical volume "/dev/rdisk/disk16" has been successfully created.

[Analyst]

Hi Keith,

Now pvcreate is working fine .
Then carryon your vgcreation activities , incase of any errors we can solve it.

if not we will look the dd error.

Thanks,
Analyst.

[Animesh Chakraborty · Accepted solution]

hp-ux 11.31 is different.
You need to read the manual before trying to create VG.

example of vgcreate command

##vgcreate -V 2.0 -s 16 -S 2t /dev/vg01 /dev/disk/disk16

now vgcreate command takes care of the
mkdir /dev/vgxx and mknod command itself.

do #ioscan -m dsf to check the device file

and man vgcreate on your hp-ux 11.31 box

[Animesh Chakraborty]

Hi Keith,
Please read the error mesg carefully

root@shlodb01 /]# vgcreate -p 8 /dev/vgname /dev/disk/disk16
Increased the number of physical extents per physical volume to 3839.
vgcreate: Volume group "/dev/vgname" could not be created:


It is complaining abount number of physical extent.

[Keith Winger]

Creating the as a version 2 worked.

Thanks all who helped.

[root@shlodb01 /]# vgcreate -V 2.0 -s 8 -S 2t /dev/vg01 /dev/disk/disk24 /dev/disk/disk25 /dev/disk/disk26 /dev/disk/disk27
Volume group "/dev/vg01" has been successfully created.
Volume Group configuration for /dev/vg01 has been saved in /etc/lvmconf/vg01.conf

[Carlos M.J.]

Hi, did you tried to increase the Physical Extension Size (pe_size) when creating the VG?

Try to do the same using the -s parameter:

vgcreate -p 8 -s 16 /dev/vgname /dev/disk/disk16

By default pe_size is 4MB but you can change it to a power of 2 (1, 2, 4, 8, 16, 32....)

Hope it helps.