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Community Member

Questions about concurrent prepositioning

Hi people,

I'm back with a prepositioning issue.  I was reading about and found that a single central WAE can handle only 24 simultaneous tasks at a time.

The problem here is that I can't understand if this 24 simultaneous tasks runs all at the same time from the differents remote WAE's or if first runs one and when it finish then start to run another task.  What happen if one of the remote WAE's has problems with the preposition task and has to abort it?  This finish all the prep works in the rest of the WAE's or there are different task?

Thanks for your help,

                              Guzmán.

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Cisco Employee

Re: Questions about concurrent prepositioning

Hi Guzman,

Answers for you:

The 24 simultaneous tasks  runs all at the same time from the differents remote WAE's or if first  runs one and when it finish then start to run another task.

Ans: This is talking about 24 concurrent tasks at any time.

What happen  if one of the remote WAE's has problems with the preposition task and  has to abort it?

Ans: That WAE might show the preposition failure depnding upon the result.

This finish all the prep works in the rest of the  WAE's or there are different task?

Ans: Yes, the preposition will continue for the rest of the WAEs and may succeed.

The 24 limit is the concurrent prepositioning limitation. If you try to preposition more than 24 edge devices simultaneously, it might fail for some of the sites. Further, there is also a limit of 10GB for the preposition task to succeed. There's a limit of 10GB concurrent file transfers.If the sum of file sizes for all current file transfers to all edges exceeds 10GB, file may be skipped.

Please look at this defect: http://tools.cisco.com/Support/BugToolKit/search/getBugDetails.do?caller=pluginredirector&method=fetchBugDetails&bugId=CSCtb84428

Hope this helps.

Regards,

PS: Please mark this as Answered, if it answers your question.

3 REPLIES
Cisco Employee

Re: Questions about concurrent prepositioning

Hi Guzman,

Answers for you:

The 24 simultaneous tasks  runs all at the same time from the differents remote WAE's or if first  runs one and when it finish then start to run another task.

Ans: This is talking about 24 concurrent tasks at any time.

What happen  if one of the remote WAE's has problems with the preposition task and  has to abort it?

Ans: That WAE might show the preposition failure depnding upon the result.

This finish all the prep works in the rest of the  WAE's or there are different task?

Ans: Yes, the preposition will continue for the rest of the WAEs and may succeed.

The 24 limit is the concurrent prepositioning limitation. If you try to preposition more than 24 edge devices simultaneously, it might fail for some of the sites. Further, there is also a limit of 10GB for the preposition task to succeed. There's a limit of 10GB concurrent file transfers.If the sum of file sizes for all current file transfers to all edges exceeds 10GB, file may be skipped.

Please look at this defect: http://tools.cisco.com/Support/BugToolKit/search/getBugDetails.do?caller=pluginredirector&method=fetchBugDetails&bugId=CSCtb84428

Hope this helps.

Regards,

PS: Please mark this as Answered, if it answers your question.

Community Member

Re: Questions about concurrent prepositioning

Thanks for your answers Bhavin, after this some doubts are clear for me now.

I was reading the info in the link and I found that (until version 4.1.5) all the files in the PP task pass through the datacenter WAE and this is the problem, doesn't it?  Then the CM only coordinates the tasks and never receives/send the files of the jobs to the remote WAEs, isn`t it?  The remote WAE receives the PP task and establish a direct connection with the server, doesn't it?

But this info produces another question: I don`t understand how was this resolved in the new versions (4.2 and higher)?  The datacenter WAE doesn't make CIFS caching of the info that is PP in the remote WAEs?

Thanks for your help,

                              Guzmán

Cisco Employee

Re: Questions about concurrent prepositioning

Hi Guzman,

Answers for you:

I was  reading the info in the link and I found that (until version 4.1.5) all  the files in the PP task pass through the datacenter WAE and this is the  problem, doesn't it?

Ans: Well, it's not a problem. Basically, the requirement for any preposition task is that - the connection needs to be optimized between DC WAE and remote WAE. if the connection can not be optimzied, PP will fail.

Then the CM only coordinates the tasks and never  receives/send the files of the jobs to the remote WAEs, isn`t it?

Ans: Yes. CM only co-ordinates the PP task.

The  remote WAE receives the PP task and establish a direct connection with  the server, doesn't it?

Ans: Yes but it has to go thru the DC WAE. Otherwise it will fail.

But  this info produces another question: I don`t understand how was this  resolved in the new versions (4.2 and higher)?

Ans: I am not sure what is the issue here. This was always like this even before AFAIK.

The datacenter WAE  doesn't make CIFS caching of the info that is PP in the remote WAEs?

Ans: It does. DC WAE will cache the CIFS traffic for the PP task and then optimize it.

Basically, when you are using prepositioning, you are transparently conencting to server share just liek a CIFS share but in the backend, there is a connection from remote WAE to CIFS server thru DC wae to verify the nitty-gritty of PP like authntication, checksums, etc.

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