EMC w/ LVM bad block enabled

[Mauro Gatti]

Hi all, sysinfo told me there are some logical volumes with bad block enable:
WARNING (virgo):EMC w/ LVM bad block enabled on xxxxxxxx
So I have to suppose this is a bad thing :-)
Could You explain me why?
Can I disable this features keeping data on logical volumes whitout any problem?

Thank You

[Mark Grant · Accepted solution]

lvchange -r N /dev/vgXX/lvolXX will turn of bad block relocation. I iamgine this is important if both the hardware and software are trying to achieve the same thing. There may well be more to it that that though.

[Jakes Louw]

Yep, you have to disable BBR on EMC disks. Effectively, the EMC array already does bad block relocation, and if the OS does it as well, the block effectively gets lost.

[Sunil Sharma_1]

You should make BBR off when hardware is doign it for you.

It's mainly because EMC itself do this for you and by doing this using h/w wll give extra load to system.
Sunil

[Jakes Louw]

Sunil

Actually, I have had cases of data corruption.

[Anoop P_2]

Yes, two agents trying to do the same. This should be avoided, as it can cause undesired results. Since the hardware knows better how to do it in many cases, let it do it.

[Sundar_7]

Hi,

lvchange -r n /dev/vgXX/lvolXX will completely turn off the bad block relocation.

lvchange -r N /dev/vgXX/lvolXX will ensure the LVM is not trying to do any bad block reallocation and the BBR will be done by the storage enclosure which is transparent to LVM.

- Sundar.