From 0ae39bda8da5f1a486cf903e8b43c6f8569d71e8 Mon Sep 17 00:00:00 2001 From: Nick Craig-Wood Date: Mon, 31 Jan 2022 17:09:11 +0000 Subject: [PATCH] docs: fix and reword --update docs After discussion on the forum with @bandwidth, this rewords the --update docs to be correct and easier to understand. See: https://forum.rclone.org/t/help-understanding-update/28937 --- docs/content/docs.md | 34 ++++++++++++++++++++-------------- 1 file changed, 20 insertions(+), 14 deletions(-) diff --git a/docs/content/docs.md b/docs/content/docs.md index 0290de904..640d51337 100644 --- a/docs/content/docs.md +++ b/docs/content/docs.md @@ -1791,24 +1791,30 @@ The default is to run 4 file transfers in parallel. This forces rclone to skip any files which exist on the destination and have a modified time that is newer than the source file. -This can be useful when transferring to a remote which doesn't support -mod times directly (or when using `--use-server-modtime` to avoid extra -API calls) as it is more accurate than a `--size-only` check and faster -than using `--checksum`. +This can be useful in avoiding needless transfers when transferring to +a remote which doesn't support modification times directly (or when +using `--use-server-modtime` to avoid extra API calls) as it is more +accurate than a `--size-only` check and faster than using +`--checksum`. On such remotes (or when using `--use-server-modtime`) +the time checked will be the uploaded time. + +If an existing destination file has a modification time older than the +source file's, it will be updated if the sizes are different. If the +sizes are the same, it will be updated if the checksum is different or +not available. If an existing destination file has a modification time equal (within -the computed modify window precision) to the source file's, it will be -updated if the sizes are different. If `--checksum` is set then -rclone will update the destination if the checksums differ too. +the computed modify window) to the source file's, it will be updated +if the sizes are different. The checksum will not be checked in this +case unless the `--checksum` flag is provided. -If an existing destination file is older than the source file then -it will be updated if the size or checksum differs from the source file. +In all other cases the file will not be updated. -On remotes which don't support mod time directly (or when using -`--use-server-modtime`) the time checked will be the uploaded time. -This means that if uploading to one of these remotes, rclone will skip -any files which exist on the destination and have an uploaded time that -is newer than the modification time of the source file. +Consider using the `--modify-window` flag to compensate for time skews +between the source and the backend, for backends that do not support +mod times, and instead use uploaded times. However, if the backend +does not support checksums, note that sync'ing or copying within the +time skew window may still result in additional transfers for safety. ### --use-mmap ###