thanks this post is really informative. myself have only deployed stacking. can u tell me how is this vss diffrent from stacking? the performance or the difftence in both these tecniques..
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Well, yes and no. We eventually became convinced that the delay was primarily on the iSeries and in how quickly updates could be applied. That was not the network issue per se, but it is where we finally had to put the resources to fix the problem, and it did. How this impacted the transmit speed I still do not understand -- my only conclusion is at some level Mimix wasn't able to acknowledge fast enough and retransmission delays caused some kind of throttle-like effect. The network side was more problematic, and I never got good answers, but I fundamentally believe that, also, the iSeries was simply not able to send data fast enough to have the network link become a steady limiting factor So even when we fixed the receiving system, the sending system (which is also burdened with running production) could only send a 100mbs or so over the link, in wildly eratic highs and lows, but over time it just did not keep it busy. Maybe. HOWEVER, we continue to struggle with the WAAS devices and this particular link. We also run much more easily measured file copies over it. At times it runs very well, fast, high compression. At other times it is flakey - extremely slow (much slower than the uncompressed speed), and file transfer failures (mostly on CIFS copies in Windows). No identifiable cause, but only when compressing. Take compression off (for just that server pair) at the access list in the switch and it runs fine. I believe we are hitting some limitation in the WAAS devices. I believe that even though they show no alarm or errors that we can find, that as they get busy they fail ungracefully. I have zero evidence for this belief, but it is the only thing remaining. I suspect this may also have been playing a role in Minimix, just not so easy to see. We have (or are supposed to have) a ticket open with Cisco on the subject. Short answer: no. And after a lot of work I find the WAAS device pretty easy to tell what is wrong when things fail entirely (e.g. a connection doesn't compress), but extremely hard to find useful information when they function, but run too slowly.
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