Optimizing large files

[dtran]

Hi all,

I have a WAAS environment with one WAVE-574 configured as Central Manager, 2 WAE-674's as accelerator at the data center and a mix of WAE-502 WAE-522 at branch offices and all devices configured using the default policies. I've been doing file transfer testing between the data center and the branch office and I noticed I can see there is improvement with small files but not with large files. I don't really see the difference when I transfer a large file. I was testing with 3 files (a 30MB, a 60MB and a 160MB file). I can see a good improvement with the 30MB and 60MB files but not with the 160MB file.

And I am using WCCP for traffic interception.

Anybody has any idea why ?and what's the best way to tell if traffic is being optimized ?

Thanks in advance !!! I appreciate any inputs/suggestions !!!

D.

[Daniel Arrondo Ostiz · Accepted solution]

Good morning,

In WAAS, the size of the file doesn't have an impact on the optimization levels, what really matters is the contents of the file. If the file you are transferring is compressed or encrypted, both the DRE and LZ optimizers will have problems to optimize the connection, and in some situations, you may even see that the connection becomes slower.

If you want to test and confirm that optimization is working, I would recommend you to use big text files. With these, you will most likely see very big optimization levels, so, the difference between the normal and optimized speeds should be noticeable at first sight.

To really see if a connection is being optimized or not, the best way to do it is using the "WAE# show statistics connection" command. It will show you what kind of optimization is being applied on it, and the reduction rate. If you have many connections, it is also possible to filter by the client and server IP addresses to limit the output. Finally, you can add the "detail" parameter to see the optimization levels for each of the optimizers, so, you could for example see if DRE or LZ are helping the optimization.

I hope this helps.

Daniel

[dtran]

Hi Daniel !! Thank you very much !!! I very much appreciate your response !!!

Question: You've mentioned that optimization may not work with compressed or encrypted files. Is there any workaround for this ?

Thanks again !!!

D.

[Daniel Arrondo Ostiz · Accepted solution]

I'm afraid there isn't, due to the nature of the compression.

In simple terms,  both DRE and LZ base their operation on identifying repeating patterns in a file and either compressing them (LZ) or avoding their transfer (DRE). Unfortunately, external compression (for example, zip) will also operate on the basis that repeating patterns can be compressed, so, by the time the file arrives to WAAS, there amount of repeating patterns is minimal.

The resulting effect is essentially the same one you would get if you try to compress a zip file. The result will be almost the same as the original file, and in some situations, it can even become a bit bigger.

Of course, if you are using some other more advance optimizers, such as the CIFS AO, you will still see some noticeable benefit from them, even if the connection optimizers (TFO,DRE,LZ) are not able to achieve much.

[dtran]

Thanks Daniel !!! Your response has been very helpful !!! I very much appreciate it !!!

D.