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Bare Metal Restore Process Flow - Who knows?

Created: 28 Mar 2013 • Updated: 28 Mar 2013 | 4 comments

Hi all,

Does anyone have a document explaining the processes and data flow used when a BMR running (flow between Master server, Media server, boot server and client).

I am looking for a document like "http://www.symantec.com/connect/sites/default/files/NBU%207.x%20process%20flow%20QRC_1.pdf"

Thanks in advance.

Dominique

Operating Systems:

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Yasuhisa Ishikawa's picture

Restore flow itself is same with normal restore.

What is identical in BMR is boot process, and it varies between OS. It is hard to write down into pictures.
As far as I know, brief of recovery proces is as below.

Once boot from media or network is completed, the client to be recovered configures NICs and retrieves system configuration information from the master server, and then do some tasks like mounting SRT via NFS(UNIX only) and partitioning disks.

After All of prerestore task completed, the client requests restore to the master server as normal regarding its partitioning information.Restore of all partitions and system state is completed, the system will reboot automatically.

The last part - finalizing. Some tasks runs at this stage like fitting system configuration to the new hardware.

Authorized Symantec Consultant(ASC) Data Protection in Tokyo, Japan

dcapp's picture

Thank you Yasuhisa for your help.

Below in italic is a copy/paste from Symantect explaining how works a restore without BMR.

Do you know where I have to insert the processes of Boot Server in this doc?

I precise that my client to restore is a Windows server.

1. A restore request is received by bprd. This request could be initiated from
the Backup, Archive, and Restore GUI or from the command line
(bprestore). The request contains a list of files to be restored.
2. The bprd process queries the Image database on the master server via
bpdbm to get information required to restore the files that have been
requested. bprd identifies the images required and the media or disk on
which the images reside. If the restore is from tape, bprd writes a
neededimage file which identifies the media required for the restore, the
images required, and the position of the images on the media, and other
information relevant to the restore. For restores from disk, there is no
neededimage file.
3. The bprd process communicates with bpjobd to initiate the restore job.
The restore job would now show up in the Activity Monitor. The restore
job may show as Active even before resources are acquired.
4. For restores from tape, bprd initiates a bprd child process to manage
the restore operation. This process reads the neededimage file to obtain
the media and positioning information for the restore. For restores from
disk, no bprd child process is created and all bprd functions are handled
by the parent bprd process.
5. The bprd child process launches the bpbrm process on the media server
which will be involved in the restore operation. In doing so, the bprd child
provides the media and positioning information to bpbrm, along with the
client name and other relevant information.
6. The bpbrm process on the media server initiates both a bpbrm child
process and a bptm process . In starting the bptm process, bpbrm
provides the media or disk information required for the restore.

7.With resource requirements determined by the previous pre-processing phase, bptm sends a resource allocation request to the Job Manager,
nbjm, on the master server system, naming the media or disk that is
required for the restore. These resources must be allocated before the job
can begin.
8. The bpbrm child process is responsible for starting the tar process on the
client system to which the restore will be directed and creating a
connection between tar and bptm.

9. nbjm makes a resource allocation request to the Resource Broker, nbrb.
10. nbrb, communicates with nbemm to request and allocate the resources that
will be used for the restore. This is an over-simplification of the activities that
take place in the selection of resources by nbrb. Communications may also
occur to bpdbm (using nbproxy) on the Master Server to identify other
information relevant to resources required. This communication is not
illustrated here in order to simplify the illustration.
11. nbrb returns the resource allocation to nbjm, which forwards it to bptm.
12. bptm makes a mount request of the media specifying the tape drives on which
the media is to be mounted, or of the disk that is to be mounted. This
illustration does not identify the details of the Media Manager daemons (ltid,
txxd, txxcd, and avrd) that are involved in the mounting of the media.
13. Once the media has been mounted and bptm has positioned the media or disk to the location where the data to be restored resides, bptm spawns a child
bptm process.
14. During the retrieval of data, the parent bptm process reads data from the
media or disk and delivers it to shared memory block by block. The child bptm
process delivers the data to the tar process on the client system, which writes
the data to the client disk.
15. When the data has been restored, the tar process on the client, and the child
bptm and child bpbrm processes on the media server will exit. bptm will
unmount the media used during the restore, and then notify the Job Manager,
nbjm, that the restore operation has been completed.
16. nbjm will de-allocate the resources used during the restore by communicating with the Resource Broker, nbrb.

17. bpbrm will notify the bprd child process that the operation is completed. The bprd child process will remove the neededimage file, all processes for the
restore exit, and the restore is finished.

 

Yasuhisa Ishikawa's picture

This explains standard restore process, and this correspond to the following part in my previous post.

After All of prerestore task completed, the client requests restore to the master server as normal regarding its partitioning information.Restore of all partitions and system state is completed, the system will reboot automatically.

Boot Server is involved in boot process, so it works before the steps you worte here.

Authorized Symantec Consultant(ASC) Data Protection in Tokyo, Japan