Doubt on Multistreaming?

[sri_vani]

Hi All,

If i have one tape drive ,x servers and enabled multi streaming.

for eg:Total backups ran on weeknd =23 hrs..tape drive used in hours would be less than 23 hrs ..

Coorect me if my understanding is wrong...

As per my understanding if multi streaming enabled,a single tape drive write x no of backups simultineously on a single server as per the given settings?

[Andy_Welburn]

Essentially:

Multistreaming or multiple data streams is related to the number of jobs or STREAMS a policy/client can produce

Multiplexing is the number of consecutive jobs that can write to a drive at any one time.

They are configured in various places: storage unit, policy, schedule, etc

What is the difference between multiplexing and multistreaming?
http://www.symantec.com/business/support/index?page=content&id=TECH10085

***EDIT***

.... knew I'd seen a better T/N recently:

When to use multiplexing and multiple data streams
http://www.symantec.com/business/support/index?page=content&id=HOWTO56166

.... it does come up *a lot* on the forum:

https://www-secure.symantec.com/connect/forums/symantec-netbackup-multiplexing-and-multi-streaming-parallel
https://www-secure.symantec.com/connect/forums/multiplexing-3

....

https://www-secure.symantec.com/connect/search/apachesolr_search/multiplexing?filters=tid%3A1741&solrsort=created%20desc

[sri_vani]

Thank you Andy..

In my backup environment both multiplexing and multristreaming are enabled.

when I tried to pull the client idetails for the weekend(like elapsed time,KB,etc) and drive utilization.

Time backedup all the clients is around 419 hrs in 3 days.

and drive utilization of 6 drives are showing 232 hrs in 3 days..This confused me little..

just to get the clarification frm experts i posted this..

[Andy_Welburn · Accepted solution]

Time backedup all the clients is around 419 hrs in 3 days.

and drive utilization of 6 drives are showing 232 hrs in 3 days

But if "MULTIPLEXING" is enabled (forget multiple data streams for now) then a lot of the time those backups will be carried out at the same time on an individual drive.

e.g.

4 clients each takes exactly an hour to backup therefore:
overall time to backup all clients = 4 hours

but multiplexing is allowed whereby 2 clients can each write to a drive simultaneously, therefore:
drive utilisation = 1 hour per drive or 2 hours total
 

[sri_vani]

mmmmmm...

 more confusing..dnt know wre am doing wrong..

on 21st sep,2012 I ran tpclean -M to reset the mount times..

and I ran tpclean again on 24th sep,6:00 am

the total drive mount time is:230+

when I pull the client backups report I see total elapsed is:400+..

Thank you so much for your detailed answers..

[Andy_Welburn]

That looks reasonable to me.

mmmmmm...

 more confusing..dnt know wre am doing wrong..

I presume this is reference to the:

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/* Copyright IBM Corp. 2011 All Rights Reserved. */
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etc at the start of that post - I don't either!! I'll edit to take out.

***EDIT***

Can't edit that post - it's something to do with the attachment but what I don't know, guess we'll have to live with it!!

[sri_vani]

Hey Andy Got U..

I mis read the post which posted by earlier by U..

Thank you so much for all ur help

[sri_vani]

got it finally..