SAN Client Fiber Transport backup
The following shows a SAN client backup process.
For backups to disk, the SAN client feature provides high-speed data movement between NetBackup media servers and NetBackup SAN-attached clients. SAN-attached clients send backup data to the media server by means of Fibre Channel connections.
As part of SAN client, the FT Service Manager (FSM) is a domain layer service that resides on the master server. The FSM provides discovery, configuration, and event monitoring of SAN client resources. The FSM collects Fibre Channel information from the client and from the media server; FSM then populates the NetBackup relational database (NBDB) with the information. FSM runs as a sub-process of NBDB and writes log messages to the NBDB log. FSM interacts with the nbftclnt process on NetBackup clients and with the nbftsrvr process on media servers.
The processing steps for a SAN client backup operation are the following:
- The NetBackup master server or primary client initiates the backup. The NetBackup Request Daemon (bprd) submits a backup request to the NetBackup Policy Execution Manager (nbpem). nbpem processes the policy configurations.
All other daemons and programs are started as necessary including nbpem, nbjm, nbrb, and nbemm.
- The Policy Execution Manager service (nbpem) does the following:
Gets the policy list from bpdbm.
Builds a work list of all scheduled jobs.
Computes the due time for each job.
Sorts the work list in order of due time.
Submits to nbjm all jobs that are currently due.
Sets a wake-up timer for the next due job.
When the job finishes, it recomputes the due time of the next job and submits to nbjm all of the jobs that are currently due.
- The Job Manager service (nbjm) requests backup resources from the Resource Broker (nbrb), that returns information on the use of shared memory for the SAN client.
- The nbjm service starts the backup by means of the client daemon bpcd, which starts the backup and restore manager bpbrm.
- The bpbrm service starts bptm, which does the following:
Requests the SAN client information from nbjm.
Sends a backup request to the FT client process on the client (nbftclnt), that does the following: Opens a Fibre Channel connection to nbftsrvr on the media server, allocates the shared memory, and writes the shared memory information to the backup ID file.
- The bpbrm service uses bpcd to start bpbkar, that does the following:
Reads the shared memory information from the BID file (waits for the file to exist and become valid).
Sends the information about files in the image to bpbrm.
Writes the file data to bpbkar, optionally compresses it, then writes the data to the shared buffer.
Sets the buffer flag when the buffer is full or the job is done.
- The FT client process (nbftclnt) waits for the shared memory buffer flag to be set. It then transfers the image data to the FT Server (nbftsrvr) shared memory buffer, and clears the buffer flag.
- The nbftsrvr service waits for data from nbftclnt; and writes the data is written to the shared memory buffer. When the transfer completes, nbftsrvr sets the buffer flag.
- bptm waits for the shared memory buffer flag to be set, writes data from the buffer to the storage device, and clears the buffer flag.
- At the end of the job:
bpbkar informs bpbrm and bptm that the job is complete.
bptm sends bpbrm the final status of the data write.
bptm directs nbftclnt to close the Fibre Channel connection.
nbftclnt closes the Fibre Channel connection and deletes the BID file.