topic Re: lvcreate problem in Operating System - HP-UX

lvcreate problem

Javier Ortiz Guajardo — Fri, 24 Mar 2006 13:15:00 GMT

I want to create a raw space, so i´m using the command:

$ lvcreate -L 2048 /dev/vgxx

Then i use the command fstyp

$ fstyp /dev/vgxx/rlvoly
vxfs

I´m not using the newfs, because i want to define a raw space.

it is a bug? or i need a patch?

Please your Help.
Thanks

Re: lvcreate problem

A. Clay Stephenson — Fri, 24 Mar 2006 13:32:12 GMT

If you simply did an lvcreate then you could completely by accident reuse previously used space that happened to contain a vxfs filesystem. Frankly, I can't imagine the thought process that led you to run fstyp on a raw volume. In any event, whether or not a filesystem was laid down previously doesn't matter, if your application is using the space as a raw volume then it won't care in the least what preexisting data are there.

Re: lvcreate problem

A. Clay Stephenson — Fri, 24 Mar 2006 13:35:36 GMT

I suppose that I should add that LVM commands do all their work in the reserved areas (VGRA) of the disk. They do not affect the remaining areas of a disk so it is quite possible to read an artifact of an earlier filesystem but again a raw disk application doesn't care.

Re: lvcreate problem

Javier Ortiz Guajardo — Fri, 24 Mar 2006 14:11:56 GMT

your right, the application doesnÂ´t care the VGRA, the problem is that we are backing up this raw devices with dataprotector 5.5, so when we try to restore the information, dataprotector fails because it wants to restore the information in vxfs type.

I mean dataprotector validate the type of the area.

Please your comments!!

Thanks

Re: lvcreate problem

A. Clay Stephenson — Fri, 24 Mar 2006 14:23:48 GMT

I can't open your attachment but I can't imagine why DP would run fstyp against a raw device either. It shouldn't care. I suspect that you are trying to restore a filesystem object. It could also be a patch related issue but since you don't bother to identify your DP version or OS version, AND you didn't bother ro say that this was really a DP problem in the first place; it's difficult to be very helpful. I would post your problem in the DP area; you would probably get more meaningful answers.

Re: lvcreate problem

A. Clay Stephenson — Fri, 24 Mar 2006 19:06:43 GMT

Okay, I was able to open your attachment. There are two possible scenarios:

1) You are trying to restore over a mounted filesystem. If so then umount the filesystem.

2) The restore detected a super-block. If you are SURE that you want to blast this raw volume and are going to restore over it then dd about 10MB or so and blast the LVOL.

e.g. dd if=/dev/zero bs=1024k count=10 of=/dev/vgxx/rlvolx

You should then be able to restore over it.

Again, you should have posted this as a DP problem.