Comments on: mysql and disk space anomoloy http://alexlurthu.wordpress.com/2008/12/29/mysql-and-disk-space-anomoloy/ Straight from the heart! Thu, 17 Dec 2009 16:33:54 +0000 http://wordpress.com/ hourly 1 By: Kristian Nielsen http://alexlurthu.wordpress.com/2008/12/29/mysql-and-disk-space-anomoloy/#comment-167 Kristian Nielsen Mon, 29 Dec 2008 07:59:46 +0000 http://alexlurthu.wordpress.com/?p=56#comment-167 It is not so much for security. But by deleting the file immediately, it is ensured that the file will be removed by the operating system when it is closed, also if the application should crash during processing the file. This avoids leaving temporary files around on disk in case of crash. It is not so much for security. But by deleting the file immediately, it is ensured
that the file will be removed by the operating system when it is closed, also if the
application should crash during processing the file. This avoids leaving temporary
files around on disk in case of crash.

]]> By: Alex http://alexlurthu.wordpress.com/2008/12/29/mysql-and-disk-space-anomoloy/#comment-166 Alex Mon, 29 Dec 2008 06:45:44 +0000 http://alexlurthu.wordpress.com/?p=56#comment-166 Thanks Joshua for the interesting explanation. Thanks Joshua for the interesting explanation.

]]> By: Joshua Kugler http://alexlurthu.wordpress.com/2008/12/29/mysql-and-disk-space-anomoloy/#comment-165 Joshua Kugler Mon, 29 Dec 2008 06:23:51 +0000 http://alexlurthu.wordpress.com/?p=56#comment-165 If I'm understanding your post correctly, it makes perfect sense. On a Unix system, to make your temp file the most secure you open it, then immediately delete it. As long as it's open, you still have read/write access to the file, but no one else can open it since the file does not show up in the directory listing. Thus, df would show the space loss because it looks at the block device. du would not show it because it walks the tree to find its file size counts. If I’m understanding your post correctly, it makes perfect sense. On a Unix system, to make your temp file the most secure you open it, then immediately delete it. As long as it’s open, you still have read/write access to the file, but no one else can open it since the file does not show up in the directory listing.

Thus, df would show the space loss because it looks at the block device. du would not show it because it walks the tree to find its file size counts.

]]>