diff options
Diffstat (limited to 'doc')
| -rw-r--r-- | doc/guix.texi | 24 |
1 files changed, 23 insertions, 1 deletions
diff --git a/doc/guix.texi b/doc/guix.texi index ba7bb9612e..22bddf10e3 100644 --- a/doc/guix.texi +++ b/doc/guix.texi @@ -12086,13 +12086,20 @@ in advance, so @command{guix publish} does not add a prevents clients from knowing the amount of data being downloaded. Conversely, when @option{--cache} is used, the first request for a store -item (@i{via} a @code{.narinfo} URL) returns 404 and triggers a +item (@i{via} a @code{.narinfo} URL) triggers a background process to @dfn{bake} the archive---computing its @code{.narinfo} and compressing the archive, if needed. Once the archive is cached in @var{directory}, subsequent requests succeed and are served directly from the cache, which guarantees that clients get the best possible bandwidth. +That first @code{.narinfo} request nonetheless returns 200, provided the +requested store item is ``small enough'', below the cache bypass +threshold---see @option{--cache-bypass-threshold} below. That way, +clients do not have to wait until the archive is baked. For larger +store items, the first @code{.narinfo} request returns 404, meaning that +clients have to wait until the archive is baked. + The ``baking'' process is performed by worker threads. By default, one thread per CPU core is created, but this can be customized. See @option{--workers} below. @@ -12118,6 +12125,21 @@ Additionally, when @option{--cache} is used, cached entries that have not been accessed for @var{ttl} and that no longer have a corresponding item in the store, may be deleted. +@item --cache-bypass-threshold=@var{size} +When used in conjunction with @option{--cache}, store items smaller than +@var{size} are immediately available, even when they are not yet in +cache. @var{size} is a size in bytes, or it can be prefixed by @code{M} +for megabytes and so on. The default is @code{10M}. + +``Cache bypass'' allows you to reduce the publication delay for clients +at the expense of possibly additional I/O and CPU use on the server +side: depending on the client access patterns, those store items can end +up being baked several times until a copy is available in cache. + +Increasing the threshold may be useful for sites that have few users, or +to guarantee that users get substitutes even for store items that are +not popular. + @item --nar-path=@var{path} Use @var{path} as the prefix for the URLs of ``nar'' files (@pxref{Invoking guix archive, normalized archives}). |