Current Active Optimized TCP Preposition Flows: 24 - Limit ?

[anthony.brewley]

Hi all

I have 2 x wae-7341 devices in a farm at our data centre.  I have a preposition job running to serve some data to approx 100 edge SRE's. 

This has been running for a few nights (due to schedule) and I have been checking b/w usage at our core WAN link.

This only ever reaches approx 1/3 of capacity and I started wondering why we were not driving more data.

Looking at the 2 x 7341's it appears that the TCP preposition flows never reach above 24 per 7341 at any one time.

Is 24 a maximum number of pp flows ? If not, any idea why this number may be so low as I have asked the PP job on the CM to PP to approx 100 sites concurrently ?

We are running 4.3.3 s/w.

7341 (a)

Current Active Optimized Flows:1097

   Current Active Optimized TCP Plus Flows:1060

   Current Active Optimized TCP Only Flows:13

   Current Active Optimized TCP Preposition Flows:24

7341 (b)

Current Active Optimized Flows:1012
   Current Active Optimized TCP Plus Flows:979
   Current Active Optimized TCP Only Flows:5
   Current Active Optimized TCP Preposition Flows:24

thanks

Anthony

[ktunugun · Accepted solution]

Hi Anthony,

Only 24 downstream Cisco WAAS devices at a time can actively receive prepositioned files from a single core Cisco WAE. Additional Cisco WAAS devices assigned to a prepositioning job must wait for the completion of one of those processes. This delay must be taken into account when sizing a Cisco WAAS deployment for CIFS prepositioning.

Given a maximum of 24 prepositioning task processes per core Cisco WAAS device, specifying more than 24 destination sites can significantly extend the time required to complete a prepositioning job. Verify that all files in the prepositioned directory are actually needed at all sites. If they are not, construct multiple prepositioning jobs segregating the sites to receive only those files required. If all files are needed at more than 24 sites, divide the prepositioning job into multiple prepositioning tasks that start at different times

Regards

Kiran.

[anthony.brewley]

Kiran

Thanks sincerely for the reply. 

I suspected this may be the case but have been unable to find this '24' limit, documented anywhere.

Could you point me in the direction of any documentation which 'officially' confirms this.

thank you

Anthony

[ktunugun · Accepted solution]

Hi Anthony,

I was able to find the below document:

https://communities.cisco.com/community/search.jspa?q=klanzill_cifs_prepos_primer.pdf&resultTypes=DOCUMENT&resultTypes=MESSAGE&resultTypes=COMMENT&communityID=2171

Regards

Kiran.

[anthony.brewley]

Kiran

thanks once again, this is very very helpful. 

regards

Anthony

[ktunugun]

Hi Anthony,

Please see the correct URL below:

https://communities.cisco.com/docs/DOC-12826

Regards

Kiran.