Bad blocks and LVM2 volume groups

Nutria · 05-23-2013, 10:38 AM

Hi,

Does "mkfs.ext4 -c ... /dev/backup_vg/backup_lv" actually do anything?

The command doesn't fail, but is bad block checking only really valid on physical devices?

gdizzle · 05-23-2013, 05:53 PM

Your making the filesystem, with the option that checks the device for bad blocks before creating the file system on the Logical Volume.

The Logical Volume contains the Volume Group which contains the Physical Volumes.

Hope this makes sense.

Nutria · 05-23-2013, 05:59 PM

Quote:

Originally Posted by gdizzle

Your making the filesystem, with the option that checks the device for bad blocks before creating the file system on the Logical Volume.

The Logical Volume contains the Volume Group which contains the Physical Volumes.

Hope this makes sense.

What you write is accurate, but how does it relate to my original question?

gdizzle · 05-23-2013, 06:21 PM

Well if the Logical Volume contains the Volume Group that contains the Physical Volumes, wouldn't it be the same, as doing a badblocks on the Physical Volumes as they are contained in the Logical Volume?

Nutria · 05-23-2013, 06:32 PM

Quote:

Originally Posted by gdizzle

Well if the Logical Volume contains the Volume Group that contains the Physical Volumes, wouldn't it be the same, as doing a badblocks on the Physical Volumes as they are contained in the Logical Volume?

Maybe. It depends on how much translation the lvm2 layer does.

chrism01 · 05-23-2013, 08:48 PM

I'd say it depends on how mkfs does the checking eg say 3 x rw and check reads agree with writes?
Of course, I'd expect 3 different writes, not the same pattern 3 times.