Multi Stream Backups

[Mouktar]

Hello All and thank your expertise in this subject.

We are running networker 7.2.1 on Win2K3 server with 4 drive autchanger library. I notice that when one backup is running, it utilizes only one drive, and thus takes longer.

Is there a way multi stream the backup process/sessions so it will use all 4 drives simultaniously instead of one drive?

Thanks in advance.

 

[Rexxy]

are you backing up via SaveGroup?

what is the savegroup parallelism set at ?
what is the client Para set at ?

is it sending more than one stream to the 1st device ?
if so, then this is where you need to change things...

change all 4 devices to be stream "1", then it will run in the following manner:
1. 1st stream will be get drive 1
2. the next saveset will get the drive 2
3. and the next on drive 3
4. then the 4th will goto drive 4
5. then the 5th will goto drive 1
6. drive 2..
7. drive 3

if your 1st device is set to 4 it gets the 1st 4 saves......

 

[Mouktar]

Thank you Rexxy.

Each device is set to 4, and I set each group to 4 and at the server level, it is set to 16.

I have 4 or 5 groups, so I guess this means leave everything else as is, and change each device to be at 1.

This makes really a sense, but the docs from legato was very confusing.

Thanks indeed.

 

[Mouktar]

Hi

I've reconfigure the devices to use 1 for the target sessions, but have one quick question.

What is Stream considered?

Would this be any backup request?

For example: If there is one group with 4 clients, does this mean each client will be backed up with one device so all 4 clients get backed up simultaniously?

Another example: If I have a client with multiple resources like drive C and Drive D, does this mean each resource gets to one device?

Just to get a better understanding...


Thanks in advance..

 

[605]

One parameter has not been mentioned at all: the server parallelism. It is THE determing factor. Guess what the default value is?

The save savet is what you backup by one "save" command:
- it could be as small as a single file
- it can be a whole partition

Thus - if you have multiple partitions, and the client's save set list is set to ALL, this will resould in multiple save sets.

Whether they are sent to all drives, this depends on the setup like the "parallelism" values but especailly on the fact how many pools are active at this time. You need at least one device per pool.

 

[Mouktar]

Thank you all for all your support.

 

[dcarlen]

The only way multiple drives will be running at the same time is if there are multiple groups running at the same time.

(The device setting in the pools)

Check all of the devices drive 1-4 This will allow the save group to use any availble drive. So, when your tape becomes full the auto changer will load the next tape into an unused drive and continue on. This will save a little time because you won't have to wait for the device to eject and then load.

The other way would be to split up your clients(streams) into more groups and run them at the same time. Max devices =Max groups that can run at the same time. in your case 4

 

[605]

Hi dcarlen,

but how long do you use NetWorker? - Sorry to say that but
you just screwed up the facts completely.

- As long as you do not limit the "savegroup parallelism"
the number of streams has nothing to do with the number
of groups at all.
One group could use all your max. streams already.
- Using devices for pools is dangerous and unnecessary
(except for rare cases). Just look at the pool Default:
although it has no devices selected - which you are not
allowed to change - it is able to receive data.
- Whether you specify all drives in a pool or none - it
has the same effect.

Test it. Try it. Play with it.

 

[Rexxy]

ditto...

 

[Mouktar]

Ok. Thanks Guys.

This has worked for me. I have 4 groups that don't start the backup at the same time. But the issue I had was having multiple clients in the same group to utilize more than one device. Initially, when the group starts, a tape would be loaded into the drive, and the first client would get backed up, and the second, on so on, so forth, utilizing only one tape drive until that tape is full. Than it loads another tape into the 2nd drive, and continues. This worked fine, but would take longer time to backup.

So, what I wanted to do was speading the backup process for the backup group.

For this, I have changed the target session for each device to be at 1 as suggested by Rexxy. I watched the backup process as the group started. I noticed right away that all 4 drives were being utilized at the same time for the same group. This has increased the backup process much faster.

Thanks again all.