Hi Rob, This is excellent information, thank you very much.
I had considered a large RAM cache setting (ram_cache) with just a small disk cache, but the ATS documentation was very vague about what this would mean. The documentation refers to the ram cache as a place where popular items are promoted, inferring (to me at least) that the size of the disk cash would always have to be larger than the ram cache, in order make full use of the ram cache. As you say though, I prefer the RAM disk path. Thanks again, Nick From: Robert O Butts <[email protected]> Reply-To: "[email protected]" <[email protected]> Date: Wednesday, April 7, 2021 at 12:54 PM To: "[email protected]" <[email protected]> Subject: Re: RAM disks for cache? Yes, we have some similar servers in Production. We use ramdisks, it works fine. You could also theoretically give ATS a large memory cache and small disk (proxy.config.cache.ram_cache.size). But then that cache is shared across all remaps, and you lose the control of different volumes for different domains, and ATS just generally isn't really designed for that. We've found ramdisks to work better in practice. I will note, our servers like this also have poor CPUs. We thought this would be ok when we bought them, but it turns out you really kind of need decent CPU for things like SSL, and poor CPUs also tend to have poor PCI lanes, which are important. Our servers like this tend to cap out around 10Gbps, despite +20Gbps NICs. I don't know if yours are similar, but if your memory-poor servers are also CPU-poor, you might have the same bottlenecks. And that's not ATS' fault, it seems unlikely any other caching proxy could do better. On Wed, Apr 7, 2021 at 10:12 AM Nick Dunkin <[email protected]<mailto:[email protected]>> wrote: Hi, I am being asked if Traffic Server can be efficiently run (or run at all) on a disk poor, memory rich server. The specifics are out of scope for this forum, but the short version is that I’m being asked to make use of some existing hardware. I was considering creating a RAM disk from the several hundred GB of available memory on these servers. Does anyone have any experience of running Traffic Server this way? Thanks, Nick Nick Dunkin Director, Software Engineering Manager – Architecture and New Product Introduction o: +1 678.258.4071 e: [email protected]<mailto:[email protected]> [[email protected]]
