On Thu, 2008-02-14 at 13:51 -0500, Andrew Culver wrote: > I have two web servers both mounting the same file system (with GFS). I > have a third web server which is independent from the first two, using > only its own local file systems. I need to mirror a directory within the > shared file system on the first two web servers to the local file system > on the third web server. To maintain redundancy, both of the first two > web servers will be pushing the files to the third web server via rsync > started up by cron as well as on-demand by the web developers. > > My concern is that if rsync is running on the first two web servers at > the same time, that there may be a chance for the two rsync sessions to > write to the same file(s) on the third web server at the same time, > possibly corrupting the files or interrupting the transfers. > > Is there any sort of locking mechanism built in into rsync to prevent > this from happening?
Rsync does no file locking. Multiple rsync processes writing concurrently to the destination generally won't make a terrible mess since each process updates a file by writing the new data to a temporary file and moving it over the original, but the processes may waste resources by duplicating each other's work. If you're using --delete, the processes might delete each other's temporary files, which could cause a problem; to avoid that, either protect the temporary files with --filter=P_.*.?????? or have each process use its own --temp-dir outside the destination. > Would running an rsync daemon on the third web > server versus running it under an ssh shell make any difference to this? The rsync daemon has a "max connections" setting that you could use to prevent the first and second hosts from pushing at the same time. Matt -- To unsubscribe or change options: https://lists.samba.org/mailman/listinfo/rsync Before posting, read: http://www.catb.org/~esr/faqs/smart-questions.html
