topic Re: Bad Block Relocation in Operating System - HP-UX

Bad Block Relocation

boomerang — Thu, 16 Dec 2010 14:06:13 GMT

Hi Admins,

Can any one explain me how does Bad Block Relocation works ? and how the does the lvm sub system manage it ?

Re: Bad Block Relocation

Torsten. — Thu, 16 Dec 2010 14:19:21 GMT

No need to do this, because it is obsolete since 11.23.

On 11.11 it should be disabled.

Many years ago if the LVM detecs bad blocks, it disabled the PE and used another PE from spare.

Now the disk does this on its own, and it does is better...

Re: Bad Block Relocation

boomerang — Thu, 16 Dec 2010 14:29:37 GMT

Is the BBRA still present in the LVM structure of 11.23/11.31 ?

Re: Bad Block Relocation

Torsten. — Thu, 16 Dec 2010 14:33:27 GMT

This is from 11.31:

#lvdisplay -v /dev/vg00/lvol1|head 20h -n 20
--- Logical volumes ---
LV Name /dev/vg00/lvol1
VG Name /dev/vg00
LV Permission read/write
LV Status available/syncd
Mirror copies 1
Consistency Recovery MWC
Schedule parallel
LV Size (Mbytes) 2000
Current LE 250
Allocated PE 500
Stripes 0
Stripe Size (Kbytes) 0
Bad block off
...

see last line above.
Same for 11.23.

Re: Bad Block Relocation

rajesh_32 — Thu, 16 Dec 2010 18:06:08 GMT

Refer:
http://h20000.www2.hp.com/bc/docs/support/SupportManual/c01919369/c01919369.pdf
Pg 14

Previously used with local disk and None for disk from Storage.
-r N with lv create
Bad block NONE

Re: Bad Block Relocation

Ismail Azad — Thu, 16 Dec 2010 18:29:35 GMT

Hi,

Traditional LVM used the bad block relocation wherein an area called as BBRA was reserved on a disk that was managed by LVM. In early days of LVM, the bad sectors and the irregularities where sent to the BBRA and that is how it was managed. However, in 11.31 software bad block relocation is disabled and is under the sole control of the disk firmware itself...

Regards
Ismail Azad