FWIW, a read operation which returns the offset the data came from will be better then using a separate control operation to find out the next offset. In other words, you want a read that starts at the current offset, but skips missing data and returns the first offset where it found data. It's always more efficient to have a single system call to do what you want. Sometimes it doesn't matter, but I'm pretty sure it will in this case. From: openssh-unix-dev <openssh-unix-dev-bounces+herbie.robinson=stratus.com@xxxxxxxxxxx> On Behalf Of Lionel Cons Sent: Wednesday, March 5, 2025 2:45 PM To: openssh-unix-dev@xxxxxxxxxxx Subject: Re: Support for transferring sparse files via scp/sftp correctly? You don't often get email from lionelcons1972@xxxxxxxxx<mailto:lionelcons1972@xxxxxxxxx>. Learn why this is important<https://aka.ms/LearnAboutSenderIdentification> SMART Modular Security Checkpoint: External email. Please make sure you trust this source before clicking links or opening attachments. On Tue, 4 Mar 2025 at 11:01, Lionel Cons <lionelcons1972@xxxxxxxxx<mailto:lionelcons1972@xxxxxxxxx>> wrote: > > Does OpenSSH scp/sftp mode transfer sparse files correctly, i.e. are > holes skipped and not transferred as chunks of 0 bytes? [1] > > We're asking about sparse files in the >= 1PB range, which consists of > multi-TB holes with around 600-2000GB of valid data. > > [1] Note the difference: Sparse files can have data sections which > consist of valid 0 bytes. Holes in sparse files represent regions > where no data space is allocated, but they read as 0 bytes > > Lionel I filed https://bugzilla.mindrot.org/show_bug.cgi?id=3798<https://url.us.m.mimecastprotect.com/s/lb17C4xGJxS9676nTBiWU4e09Y> for sparse file copy support Lionel _______________________________________________ openssh-unix-dev mailing list openssh-unix-dev@xxxxxxxxxxx<mailto:openssh-unix-dev@xxxxxxxxxxx> https://lists.mindrot.org/mailman/listinfo/openssh-unix-dev<https://url.us.m.mimecastprotect.com/s/Q2rVC5yKgyFpRWRzT2s0UkdF5d> _______________________________________________ openssh-unix-dev mailing list openssh-unix-dev@xxxxxxxxxxx https://lists.mindrot.org/mailman/listinfo/openssh-unix-dev
