-size-only
indicates that rsync will skip documents that match in dimension, even if the timestamps vary. This means it will synchronise fewer documents than the default behavior. It will miss any document with changes that wear't have an effect on the general file size. If you have got something that shifts the schedules on files without changing the data files, and you don't desire rsync to spend a lot of period checksumming those documents to find out they haven't transformed, this will be the option to use.-ignore-times
indicates that rsync will checksum every document, actually if the timestamps and file sizes fit. This means it will synchronise even more data files than the default behavior. It will consist of changes to files even where the document size is definitely the same and the changes time/time has long been reset to the authentic worth. Checksumming every document means it has to be entirely read through from cd disk, which may become gradual. Some develop pipelines will reset to zero timestamps to a specific date (like 1970-01-01) to ensure that the last build file is reproducible little bit for little bit, e.gary the gadget guy. when packed into a tar file that will save the timestamps.-ignore-times
does even more than its name suggests. It ignoresboththe time and dimension.In comparison,-size-only
will precisely what it states.rsync
provides three ways to determine if a document is usually outdated:rsync
uses just 1 and 2. Both 1 and 2 can end up being acquired jointly by a solitarystat
, whereas 3 demands reading the whole file (this is usually 3rd party from reading through the document for transfer). Presuming just one changer is selected, that means the right after:-size-only
, just 1 is carried out - timestamps and checksum are usually disregarded. A document is duplicated unless its dimension is similar on both finishes.-ignore-times
, neither of 1, 2 or 3 is certainly performed. A document is usually replicated.-checksum
, 3 is usually utilized inadd-onto 1, but 2 will benotcarried out. A document is replicated unless dimension and checksum suit. The checksum is definitely only computed if dimension matches.-size-only
, the two documents are deemed the same:-ignore-times
, the two data files are regarded different:-ignore-times
has any impact at all.