Hi, I create a pool mirrored with 1gb of space. After I create a file system in that pool and put a file (file1) of 300MB it that file system. After that, I create a snapshot in the file system. With the zfs list command the space used by the snapshot is 0 (zero). It?s ok. Well after that I copied the file of 300 mb to a another file (file2) in the same file system. Listing the files in the file system I can see the two files and listing the files in the snapshot I can see only the first file. It?s ok too, but the zfs list now shows that the snapshot uses 23.5KB of space. I suppose that the copy of the file1 change the atime of the inode and for this reason the inode of the file1 needed to be copied to the snapshot using the space of the snapshot. I tried to set the atime to off, but the space of 23.5KB of the snapshot still being used after the copy of the file. Anyone knows the reason the snapshot uses that 23.5kb of space? Thanks, Silvio This message posted from opensolaris.org
Silvio Armando Davi <silvio at leeway.com.br> writes:> Hi, > > I create a pool mirrored with 1gb of space. After I create a file > system in that pool and put a file (file1) of 300MB it that file > system. After that, I create a snapshot in the file system. With the > zfs list command the space used by the snapshot is 0 (zero). It?s ok. > > Well after that I copied the file of 300 mb to a another file (file2) > in the same file system. Listing the files in the file system I can > see the two files and listing the files in the snapshot I can see only > the first file. It?s ok too, but the zfs list now shows that the > snapshot uses 23.5KB of space. > > I suppose that the copy of the file1 change the atime of the inode and > for this reason the inode of the file1 needed to be copied to the > snapshot using the space of the snapshot. I tried to set the atime to > off, but the space of 23.5KB of the snapshot still being used after > the copy of the file. > > Anyone knows the reason the snapshot uses that 23.5kb of space?I would guess that there is a lot more than the atime that needs tracking. The containing directory at the destination has changed, so the "before" version of that would take up space. I think that free space maps go in there too. Others will probably be able to answer more authoriatatively Boyd