Re: read and write back full disk to trigger relocation

From: David Christensen <dpchrist_at_holgerdanske.com>
Date: Mon, 29 May 2023 07:04:41 UTC
On 5/28/23 04:12, Artem Kuchin wrote:
 > I have a 3TB gmirror raid

On 5/28/23 14:45, Sysadmin Lists wrote:
> Artem Kuchin May 28, 2023, 4:12:21 AM
>> If course i can run full disk read once in a while, but i'd rather
>> prefer to read  and write the data back, so it sector
>> is damaged it can trigger relocation.
> 
>  From the dd(1) manpage:
> 
>       Do a refresh of a disk drive, in order to prevent presently recoverable
>       read errors from progressing into unrecoverable read errors:
> 
>             dd if=/dev/ada0 of=/dev/ada0 bs=1m


gmirror(8) examples indicate the device node should be:

/dev/mirror/name


Where "name" is the argument provided when the mirror was created:

# gmirror label name prov ...


> That won't trigger relocation, but it will refresh the decaying data.


Do you have a URL for an engineering document or standard that describes 
drive sector reallocation?  STFW "drive sector reallocation" I do not 
see anything that looks authoritative (e.g. disk manufacturer or 
standards body).


David