<div dir="ltr"><div class="gmail_extra"><div style="font-family:arial,sans-serif;font-size:13.333333969116211px">How many concurrent client connections do those 6000 concurrent users generate? You'll need to make sure you have enough available worker threads to accommodate those users plus extra to soak up traffic spikes, ideally.<br>
</div><div style="font-family:arial,sans-serif;font-size:13.333333969116211px"><br></div><div style="font-family:arial,sans-serif;font-size:13.333333969116211px">a) One thing to consider with a single instance architecture is the lack of redundancy. If that host goes down, your site is down. </div>
<div class="gmail_extra" style="font-family:arial,sans-serif;font-size:13.333333969116211px">b) Do you mean have persistent client connections to backend, like websockets? Or have varnish make backend requests through persistent connections. The former is possible, the latter is the default behavior as I understand it -- Varnish will always attempt to reuse an existing connection for the next backend request.</div>
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