MSA Storage

Flow of data when taking a backup.

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Sezgin Rafed
Occasional Contributor

Flow of data when taking a backup.

Hi everyone,

We have the following SAN setup:

HP Fiber channel switches,HP EVA 5000,HP Proliant Servers with Fiber channel HBAs,HP MSL6030 Tape Library with a NSE1200-160 Network Storage Router Card(1 Fiber Channel port connected to a Fiber switch).

One of the Proliant Servers(Server A) is running CA Brightstor Enterprise backup(SAN and Tape Library Options up and running).
Another Server(Server B) is running SQL Server 2000 Enterprise Ed. and has a Brightstor SQL Agent installed. The SQL Database files are on the EVA. The Tape Library,the LTO Drives and the NSE1200 are listed under Server B's Device Manager. There is a Brightstor Backup Job, backing up a database on Server B(through Brightstor SQL Agent)

My question is:

How does the data flow when the backup job is running - does the Brightstor SQL Agent send the data directly to the NSE1200 over Fiber or does the data go through Server A ?

In my understnding,the only way to the Tape Library is through NSE1200,so whoever/whatever sends data to the Library has to have a physical link over fiber to NSE1200 and also has to be capable of talking to it(to issue the right commands).

Any assistance will be greatly appreciated.

Best regards.
Timothy Cusson
Valued Contributor

Re: Flow of data when taking a backup.

You are correct, if the tape library (aka chnager, aka robot) and LTO tape drives are only listed on server B and not on server A device manager list, then, all backup data must flow through server B fibre channel adapter, then the fibre SAN switch, then the NSE1200 fibre to SCSI adapter, then either to the robot or one of the tape drives.

Therefore, with this configuration, you are only using the NSE1200 as a fibre to SCSI converter. The result is a transparent conversion, Windows 200x sees the changer (library) and LTO tape drives as if they were directly connected SCSI devices. (The NSE1600 is never seen, it is only a converter or router, similar to the SAN switches which are not seen.)

As a best practice, the NSE1200 should be in a separate switch zone with only the backup server and the optional backup media servers. In your case, it seems you have it zoned with server B and the NSE1200, this is why the library/changer and tape drives are only seen by server B.

As an experiment, you could change the zoning such that the library and tape drives are removed from server B and attached to server A. Now the library and LTO drives are seen as SCSI devices on server A only, not B. Now, re-run the same backup jobs to determine if it's more efficient to have to data flowing through server A.

Another configuration, setup the backup zone to include server A, server B and the NSE1200. Now both server A and server B see the library/changer and LTO drives as directly attached SCSI devices in their Windows Device Manager lists. Using the CA backup software, you can assign one LTO drive to server A and one LTO drive to server B thus implementing manual load balancing. Now both server A and server B can simultaneously push data down to LTO drive 1 and drive 2.