Spurious characters in LVMTAB

[Andy Smith_1]

are the spurious characters in this lvmtab the result of someone trying to vi it, or do they have a function and if so what ?
/dev/vg00
X]@*1
/dev/dsk/c3t5d0
/dev/dsk/c1t3d0
/dev/vg02
X]@*7j
/dev/dsk/c3t6d0
/dev/dsk/c1t5d0
/dev/vg03
X]@*:
/dev/dsk/c1t6d0
/dev/dsk/c0t6d0

[T G Manikandan]

Hello

The type of the lvmtab is 'data'.
YOu cannot do a vi into that.

#strings /etc/lvmtab
should show you the contents.


Thanks

[steven Burgess_2]

Hi Andy

I havee seen this on a couple of our boxes. Not sure why it happens though

You can recreate lvmtab by moving it to lvmtab.bak and performing a

vgscan -a

This will recreate lvmtab. The only problem being that it won't be in descending order by volume group

man vgscan

for more options

Hope this helps

Steve

[steven Burgess_2]

Hi

T G

Have seen this even after

strings /etc/lvmtab

What do you think may be the cause ?

Steve

[T G Manikandan]

Yes,
you have the volume group with the physical disk information in it.It has the table where the volume groups and the associated physical volumes in each group.
If sometime your lvmtab file is corrupt then
you should do a vgscan -a
to rebuild the lvmtab file.

[Bill McNAMARA_1]

These characters are not a problem.
Your lvmtab is not corrupt.
files /etc/lvmtab reports the file is data.

strings /etc/lvmtab extracts the printable characters.. which do not always report just device files.

A vgscan recreation can mess up your pvlinks configuration(alternate paths) very easily causing serious perf degradation.. make sure you know what you're doing.

Later,
Bill

[Bill McNAMARA_1]

Looking at your vg03 for example, vgscan will reconfigure it as:

/dev/dsk/c0t6d0
/dev/dsk/c1t6d0

the other vgs will also be swapped. vgscan recreates in numberical order of device file...

Later,
Bill

[Thierry Poels_1]

Hi,

/etc/lvmtab is NOT a textfile, and should be edited manually.

"strings /etc/lvmtab" will also show some rubbisch in many cases. "strings" only tries to filter out non-text data, but can never really know what is what.

regards,
Thierry.

[Shahul]

Hi

lvmtab is not a text file. It normally contains some unreadable charecters. It is not because of somebody is doing vi. If U doubt like this it is always better to keep a copy of lvmtab. For seeing the contents of lvmtab

#strings /etc/lvmtab

Best of luck
Shahul

[James R. Ferguson · Accepted solution]

Hi Andy:

The /etc/lvmtab is a binary data file. As noted, 'strings /etc/lvmtab' will expose the printable characters. The file is not and should not be editted manually in any fashion.

The file actually contains the physical device paths for each volume group defined to the system. In addition, the VGID (Volume Group Identification) and some other state information about each volume group is recorded.

As Bill has aptly noted, do *not* capraciously run 'vgscan'. This may reorder the primary and alternate paths to a volume group leading to non-optimal performance. It is the order of the paths in /etc/lvmtab that determines which is a primary and which as an alternate (secondary) pvlink. For vg00, boot information may become incorrect due to reordering of devices following a 'vgscan'. See the 'vgscan' man pages for more information.

Regards!

...JRF...