Legato uses only one LTO Drive 1

[sdohn]

I'have one Tape Pool and the 4 LTO Drives are enabled for this Pool. And I have one big group with 200 Clients.
But Legato uses only one of the four LTO Drives for the backup Jobs. How can I reduce the backup Time, so that Legato uses every 4 LTO Drives available.

 

[605]

Did you increase the server parallelism at all? By default it is set to 4, not allowing more than 4 streams to be opened at any time. As the device parallelism is also set to 4 by default, this is the consequence.

 

[new2me]

I learned from the pass it is better not to put restrictions on the tape devices... I would start going into the pool and 'de-select' the devices and keep an eye on the next backup.

 

[Chacalinc]

Performance is ruled by 3 settings:

1. as 605 stated: server parallelism. It should be the sum of all target sessions.

2. Target sessions. max number of streams (save sets) that a tape drive will receive. It is tape-based configuration.

3. client paralllism. (Actually, I don't remember the exact name, if 605 can help me out with this name). It is configured in the Client Resource (as advance configuration), it sets how many streams (save set) a client can send at a time (as target sessions, but it is a client-based configuration).

Cheers.

Chacal, Inc.

 

[Chacalinc]

oh, BTW, new2me stated something important, try to not select tape drives (use it *only* when you really need to limit the access to the drives).

Cheers.

Chacal, Inc.

 

[sdohn]

Thanks 605 for your valuable remarks.
An friendly Sysadmin Departmend told me,
that when you have 4 LTO Drives, all with Target sessions set to 4, and the Server Parallelism set to 16, there will be problems with the recovery of a client.
In this situation, the Networker uses only one LTO Drive for the recovery, and waits until the Tape with the next savestream which belongs to the saveset is loaded into this single drive.

How can I avoid this scenario, so that for the recovery all 4 LTO Drives get in use.

 

[605]

Please tell your friendly Sysadmin Department that it should not spread rumors like this unless it also tells you about the facts which can prove the behaviour or the problem.

Of course there is always room for a bug, but this would usually be specific to a single (or multiple ;-) NetWorker version(s) and should not be taken as general procedure. So this is the least info you should have.


This is the NW behavior, to my best knowledge:
As you can run multiple save processes at the same time, you should be able to also run multiple recoveries at the same time. However, using the GUI, this will not open more than one save stream at a time. So if you really want to start multiple recover processes, you have to open multiple winworkr windows or start multiple recover processes from the command line. Does this sound reasonable?