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

SAN & Bad Block Relocation Policy

Justin Willoughby — Mon, 17 Mar 2003 18:01:29 GMT

I have read that I should disable bad block relocation policy for disks on my HP-UX box that are on/connected via a SAN that is connected via Fibre Channel because the SAN array does the bad block relocation for me. If so and believe it is, should I do a `lvchange -r n /dev/vgname/lvname` or `lvchange -r N /dev/vgname/lvname` ?

Thanks!

- Justin

Re: SAN & Bad Block Relocation Policy

Sridhar Bhaskarla — Mon, 17 Mar 2003 18:08:41 GMT

Hi Justin,

It does not really matter as long as the LVM does not attempt to relocate a bad block which is accomplished by both options.

-r N does not even maintain a bad block directory which is a preferred option to me as we dont' want to care about the bad blocks at all.

-Sri

Re: SAN & Bad Block Relocation Policy

James R. Ferguson — Mon, 17 Mar 2003 18:12:06 GMT

Hi Justin:

For an EMC2 SAN, you want to use '-N' which prevents bad block relocation *and* the Bad Block Directory.

When done, an 'lvdisplay' of the changed logical volume will show "Bad block NONE".

Regards!

...JRF...

Re: SAN & Bad Block Relocation Policy

Marco Santerre — Mon, 17 Mar 2003 18:12:38 GMT

If you don't want Unix to handle your bad block reallocation at all, you should definitely use :

#lvchange -r N /dev/vgname/lvname

Re: SAN & Bad Block Relocation Policy

Rita C Workman — Mon, 17 Mar 2003 18:13:03 GMT

Depends on the array...we have EMC and for them we turn off the BadBlock Reallocation (since EMC handles it). To leave it on, would create confusion between the server and the array.

The command I have always used is the lvchange -r N ....

Rgrds,
Rita

Re: SAN & Bad Block Relocation Policy

Justin Willoughby — Mon, 17 Mar 2003 18:15:36 GMT

Great!

Thanks All, that answers my question!

- Justin