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cp.exe chunk size

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	cp.exe chunk size by skelker :: Rate this Message: Reply to Author \| View Threaded \| Show Only this Message Hi, Is there a reason that cp.exe uses 8KB chunk sizes to copy files? This behavior leads to very fragmented files, especially when copying large files. --skelker
	Re: cp.exe chunk size by Eric Blake :: Rate this Message: Reply to Author \| View Threaded \| Show Only this Message -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 According to skelker on 11/30/2007 2:23 PM: > Hi, > Is there a reason that cp.exe uses 8KB chunk sizes to copy files? This > behavior leads to very fragmented files, especially when copying large > files. This has been brought up before, if you want to search the archives for posix_fallocate. The problem is not with cp.exe, but with the way that the POSIX read/write functions are implemented on top of Windows system calls in cygwin1.dll. When cygwin 1.7.0 comes out, I will be experimenting with using posix_fallocate to see if that can reduce the fragmentation. But in the meantime, you'll have to just live with it. - -- Don't work too hard, make some time for fun as well! Eric Blake ebb9@... -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.5 (Cygwin) Comment: Public key at home.comcast.net/~ericblake/eblake.gpg Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFHUIR184KuGfSFAYARAkVyAKDHRbMhsJhY+9CseozooXZygU8xewCghlGj ujKefnP3WWUI4PTX5wGNCuo= =AgaY -----END PGP SIGNATURE----- -- Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple Problem reports: http://cygwin.com/problems.html Documentation: http://cygwin.com/docs.html FAQ: http://cygwin.com/faq/
	Re: cp.exe chunk size by Brian Ford :: Rate this Message: Reply to Author \| View Threaded \| Show Only this Message On Fri, 30 Nov 2007, skelker wrote: > Is there a reason that cp.exe uses 8KB chunk sizes to copy files? This > behavior leads to very fragmented files, especially when copying large > files. In addition to what Eric said about posix_fallocate, Cygwin 1.5.25 should use a 64kb chunk size. -- Brian Ford Lead Realtime Software Engineer VITAL - Visual Simulation Systems FlightSafety International the best safety device in any aircraft is a well-trained crew... -- Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple Problem reports: http://cygwin.com/problems.html Documentation: http://cygwin.com/docs.html FAQ: http://cygwin.com/faq/