Recovery steps for metadevices on Solstice disksuite

From: Vijay Raghavan (Vijay_Raghavan01@infosys.com)
Date: Tue Dec 07 2004 - 00:22:49 EST

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Hello Gurus

This is in response to my question sometime back to recover data from

external storage which is concatenated or striped. Got some responses

but still not sure of what exactly is the correct solution

This is some info I found some info on Sun-Solve which says it is
possible to recover data on concat or stripe

metadevices

I got a reply from Peter saying it is not possible but this sunsolve doc
says it is possible.

https://osc-apac.pr.sun.com/OSCSW/svcportal?pageName=OSCHomeSearchResult
s&eventSrc=getdocdetail&command=no_command&searchString=recovery%20for%2
0solstice%20disksuite&assetKey=1-9-76077-1&resource=INFODOC

I have also put the important points in brief below which I saw in this
doc

Using This Procedure With Other Metadevice Types

------------------------------------------------

* RAID-5 metadevices: This same procedure can be used on a Solstice

Volume Manager RAID-5 metadevice.

The "-k" option. When you rebuild the device in step 9, the "-k"

option is of great importance. This option tells Solaris Volume

Manager not to initialize the metadevice, but to use the data

that is already on the disk. Failure to do this causes complete loss

of existing data on the device.

* Concat or stripe metadevices (or both): This procedure can also be

used on concat or stripe metadevices, or both. Running metaclear

and metainit does not affect user data.

It is very important that stripes and concats are re-created with

each slice component in the same order. Recreating a stripe or concat

in the wrong order does no harm, so long as the data (filesystem) is

not modified (such as with fsck -y). If you accidentally re-create a

stripe in the wrong order just metaclear it and re-create it in the

correct order. If you do not know the correct order, simply repeat

the steps of metainit and fsck -n until fsck completes successfully.

Thanks

VIJAY

-----Original Message-----
From: Webmaster - ITServ GmbH [mailto:webmaster@itserv.de]
Sent: Friday, December 03, 2004 2:13 PM
To: Vijay Raghavan
Subject: Re: Recovery steps for metadevices on Solstice disksuite

You cannot recover striped or concatenated data, because striping and

concatenating does not deliver any data redundancy.

To prevent from data loss, you have to configure a mirror or raid 5. But
you

can define a striped mirror, to get performance AND redundancy.

Peter

----- Original Message -----

From: "Vijay Raghavan" <Vijay_Raghavan01@infosys.com>

To: <sunmanagers@sunmanagers.org>

Sent: Friday, December 03, 2004 9:08 AM

Subject: Recovery steps for metadevices on Solstice disksuite

> Hello Gurus

> This is slightly offtopic but would appreciate a feedback with
commands