Support for multiple logical devices on single physical
Heinz Mauelshagen
mauelshagen at redhat.com
Mon Mar 31 13:03:48 UTC 2008
On Sun, Mar 30, 2008 at 03:41:57PM -0500, Chris Adams wrote:
> Once upon a time, Chris Adams <cmadams at hiwaay.net> said:
> > # dmraid -rD
> > /dev/sda: pdc, "pdc_bacdae", mirror, ok, 585941248 sectors, data@ 0
> > /dev/sdb: pdc, "pdc_bacdae", mirror, ok, 585941248 sectors, data@ 0
> > # ls -l
> > total 40
> > -rw------- 1 root root 0 Mar 28 10:47 sda_pdc.dat
> > -rw------- 1 root root 2 Mar 28 10:47 sda_pdc.offset
> > -rw------- 1 root root 10 Mar 28 10:47 sda_pdc.size
> > -rw------- 1 root root 0 Mar 28 10:47 sdb_pdc.dat
> > -rw------- 1 root root 2 Mar 28 10:47 sdb_pdc.offset
> > -rw------- 1 root root 10 Mar 28 10:47 sdb_pdc.size
> >
> > The .offset files both have "0". The .size files have:
> >
> > sda_pdc.size:586072368
> > sdb_pdc.size:625142448
>
> I manually decoded the metadata (at an offset of 63 sectors from the end
> of sda and sdb) to see if there was anything odd, but I didn't find
> anything that jumped out at me.
>
> I then searched through the end of both drives some more and found a
> second metadata block on sdb at an offset of 49 sectores from the end.
> It does describe the second logical device on sdb properly.
>
> I've attached both decodes.
>
> It looks like pdc_read_metadata stops looking on a drive when it finds a
> metadata block.
Yes, because it expects just one metadata block total.
> Any suggestions on how that might could be changed? I
> guess that the found drives should be ordered by the device number in
> the raid struct.
Need the image of the metadata to proceed any further.
Please send the last 63 sectors of off each drive in binary.
Cheers,
Heinz
> --
> Chris Adams <cmadams at hiwaay.net>
> Systems and Network Administrator - HiWAAY Internet Services
> I don't speak for anybody but myself - that's enough trouble.
> promise_id = "Promise Technology, Inc."
<SNIP>
> 00007f0: 100f 0e0d 0c0b 0a09 0807 0605 ............
>
> raid.checksum = db890b40
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Heinz Mauelshagen Red Hat GmbH
Consulting Development Engineer Am Sonnenhang 11
Storage Development 56242 Marienrachdorf
Germany
Mauelshagen at RedHat.com PHONE +49 171 7803392
FAX +49 2626 924446
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