Re: [linux-lvm] pvmove and badsectors

Re: [linux-lvm] pvmove and badsectors

[Dieter Stueken]

Heinz J . Mauelshagen wrote:
> pvmove moves data chunk by chunk (64kB).
> 
> If such chunk read fails, it retries rereading the failed chunk sector
> by sector in order to retrieve as much data as possible.

I'm about to try it. But afterwards I like to analyze which files
are affected using "debugfs". As far as I understand the code, any
unreadable sector is zeroed. The printf reports about the unreadable
sector, but only prints the # of the sector from the input device.
Instead I'm interested on where the zeroed sector ends up on the
destionation device, to locate it later on. Questions:

the printed sector number counts 512 byte sectors?
If I run pvmove -v, it reports the PE# and LE# of the
PE currently copying. I hope I can calculate this way:

Get sector# modulo PE size to get the relative position
of the broken sector within the PE, and using the destionation
LE# + the offset to get the sector # on the LV after the
move. Right?

Suggestion:
write such informations to syslog to be sure this is
saved somewhere. If this is printed on screen olny, I may loose
this information easily and won't have any change to locate the
broken sector later on.

Dieter.
-- 
Dieter St�ken, con terra GmbH, M�nster
     stueken@conterra.de
     http://www.conterra.de/
     (0)251-7474-501

[linux-lvm] pvmove and badsectors

[Newsmail]

-i, --ignore_read_errors
        Ignore read errors while moving data. Usefull in case data is moved 
away from a  broken  or  unac­
        cessable disk (area).
Hi everybody I would like to know, if pvmove finds an unreadable block in a 
PV, does it ignore the complete PV or just the bad area? I mean if a 32MB 
PV has a bad block, the complete 32 megs get ignored, or only the 
problematic area?
thx in advance,
greg

Re: [linux-lvm] pvmove and badsectors

[Heinz J . Mauelshagen]

On Fri, Jul 11, 2003 at 12:08:57AM +0100, Newsmail wrote:
> -i, --ignore_read_errors
>         Ignore read errors while moving data. Usefull in case data is moved 
> away from a  broken  or  unac­
>         cessable disk (area).
> Hi everybody I would like to know, if pvmove finds an unreadable block in a 
> PV, does it ignore the complete PV or just the bad area? I mean if a 32MB 
> PV has a bad block, the complete 32 megs get ignored, or only the 
> problematic area?

pvmove moves data chunk by chunk (64kB).

If such chunk read fails, it retries rereading the failed chunk sector
by sector in order to retrieve as much data as possible.


> thx in advance,
> greg
> 
> 
> 
> _______________________________________________
> linux-lvm mailing list
> linux-lvm@sistina.com
> http://lists.sistina.com/mailman/listinfo/linux-lvm
> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/

-- 

Regards,
Heinz    -- The LVM Guy --

*** Software bugs are stupid.
    Nevertheless it needs not so stupid people to solve them ***

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Heinz Mauelshagen                                 Sistina Software Inc.
Senior Consultant/Developer                       Am Sonnenhang 11
                                                  56242 Marienrachdorf
                                                  Germany
Mauelshagen@Sistina.com                           +49 2626 141200
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