----- Original Message ----- > Hi folks- > I have frequently heard the complaint that ATS does not do read while > write -- that, as a reverse proxy, while an object is not yet in > cache, it forwards all connections to the origin until a version > exists in the cache. The complaint is of a thundering herd -- a new > popular object becomes available, and the origin gets immediately > flooded with requests. Part of this is likely because there are 2 > relevant configs (if not more) that need to be set in tandem for it > to work: proxy.config.cache.enable_read_while_writer (which the > documentation says is set to off by default), and > proxy.config.http.background_fill_completed_threshold, which is set > to 50% (eg, 50% of the object needs to be downloaded before it can > be used to serve other requests. > > Should we consider both turning on read while write on by default, > and reducing the background_fill_completed_threshold down to a > smaller number (5%? 1%)? What are the upsides of the current > defaults and downsides of changing them?
The main downside is that the feature isn't widely enough tested in the field by our developers, or that we haven't had enough (positive or otherwise) feedback from users. re smaller numbers: Depending on a) object size b) bandwidth of users c) size of the herd 5% or 1% may be way to small. But this is my gut speaking, I too don't have the experience in that regard. > miles > -- Igor Galić Tel: +43 (0) 664 886 22 883 Mail: i.ga...@brainsware.org URL: http://brainsware.org/ GPG: 6880 4155 74BD FD7C B515 2EA5 4B1D 9E08 A097 C9AE
