Hi James: On Mon, Apr 12, 2010 at 06:45, James Van Artsdalen <james-opensola...@jrv.org> wrote: > OpenSolaris needs support for the TRIM command for SSDs. This command is > issued to an SSD to indicate that a block is no longer in use and the SSD may > erase it in preparation for future writes.
That's what this RFE is about 6859245 Solaris needs to support the TRIM command for solid state drives (ssd) > A SECURE_FREE dataset property might be added that says that when a block is > released to free space (and hence eligible for TRIM), ZFS should overwrite > the block to zeros (or better, ones). If a dataset has such a property set > then no "stray" copies of the data exist in free space and deletion of the > file and snapshots is sufficient to remove all instances of the data. > > If a file exists before such a property is set that's a problem. If it's > really important - and it might be in some cases because of legal mandates - > there could be a per-file flag SECURELY_FREED that is set on file creation > iff the dataset SECURE_FREE is set and is reset if the file is ever changed > while SECURE_FREE is clear - this indicates if any file data "escaped" into > free space at some point. Finally an UNLINK_SECURE call would be needed to > avoid race conditions at the end so an app can be sure the data really was > securely erased. > > PS. It is faster for an SSD to write a block of 0xFF than 0 and it's possible > some might make that optimization. That's why I suggest erase-to-ones rather > than erase-to-zero. -- Pablo Méndez Hernández _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
