concurrent writes to backup files using netbackup

[sima_rangarajan]

Hi,

I am trying to study the behavior of NetBackup 6.5.

I have two policies:
policy 1: user backup policy to backup data from src1 dir on disk1 to dest1 dir on disk1
policy 2: full backup policy to backup data from src1 dir on disk2 to dest1 dir on disk2

disk1 and disk2 are configured as storage units (BasicDisk) with number of concurrent jobs set to 2.

My client, media server and master server are the same windows 2003 system.

In  host properties, under master server->client attributes, I have added my client name, and set maximum data streams to 2.
For each of the policies, I have checked the "allow multiple data streams" option.

So, from what I understand, I have everything set to enable concurrent backups.

Now for policy1, I initiate a backup from the backup, archive, and restore console for the client.
For policy2, I initiate a manual backup.

I can see both the jobs active at the same time (and not queued) in the Activity monitor, which indicates that they are running concurrently.

I took a procmon trace to study how the backups are written to the destination directories.
I see that the src file for the first job is read first and then written to the backup directory (the large img file which seems to contain all the data). Once the first backup file is completely written to, the src file for the second job is read and data is written to the backup file of the second job's dest dir.

Why are there no parallel writes happening here? The only common factor here is the same client, but I have set maximum data streams to 2 for the client. I was expecting to see parallel writes to destination directories for both the jobs and not serialized. Can someone throw some light on this?

Thanks and regards,
Sima

[Jim_Horalek]

 Out of Admin manual. The Maximum concurrent jobs setting depends on the available disk space and the server’s ability to run multiple backup processes. Very vague but it may be something in the OS, lack of threads.

[sima_rangarajan]

Not sure if that's the reason.

The destinations disks have around 4.5 GB free, and the data set I am trying to back up is 500 MB.
The system this is installed on is a windows 2003 box (with SP2), 2.2 GHz CPU and 1.5 GB RAM.
The system is dedicated for NetBackup, and I don't think thread creation should be a problem.

Thanks and regards,
Sima

[nairdheeraj]

Are both the Disk storage units on the same drive letter?

[sima_rangarajan]

No they are on different drives.

[Reagan]

It could be that the "Maximum jobs per client" property on the Master server is set to the default of 1.  which could be causing only one stream to run at a time.

Under host properties => Master Server => Properties => Global Attributes, change the Maximum jobs per client to a value greater than 1.

Restart the Netbackup services on the master server to make the change take affect and try again.

The other settings mentioned looks good to me.

[sima_rangarajan]

Well I already have that value (maximum jobs per client) set to 5.

Thanks,
Sima