Hans, > hello, > can i create a image from ZFS with the DD command?
Yes, with restrictions. First, a ZFS storage pool must be in the "zpool export" state to be copied, so that a write-order consistent set of data exists in the copy. ZFS does an excellent job of detecting inconsistencies in those volumes making up a single ZFS storage pool, so a copy of a imported storage pool is sure to be inconsistent, and thus unusable by ZFS. Although there are various means to copy ZFS (actually copy the individual vdevs in a single ZFS storage pool), one can not "zpool import" this copy of ZFS on the same node as the original ZFS storage pool. Unlike other Solaris filesystems, ZFS maintains metadata on each vdev that is used to reconstruct a ZFS storage pool at "zpool import" time. The logic within "zpool import" processing will correctly find all constituent volumes (vdevs) of a single ZFS storage pool, but ultimately hides / excludes other volumes (the copies) from being considered as part of the current or any other "zpool import" operation. Only the original, nots its copy, can be seen or utilized by "zpool import" If possible, the ZFS copy can be moved or accessed (using dual-ported disks, FC SAN, iSCSI SAN, Availability Suite, etc.) from another host, and then only there can the ZFS copy undergo a successful "zpool import". As a slight segue, Availability Suite (AVS), can create an instantly accessible copy of the constituent volumes (vdevs) of a ZFS storage pool (in lieu of using DD which can take minutes, or hours). This is the Point-in-Time Copy, or II (Instant Image) part of AVS. This copy can also be replicated to a remote Solaris host where it can be imported. This is the Remote Copy, of SNDR (Network Data Replicator) part of AVS. AVS also supports the ability to synchronously, or asynchronously replicate the actual ZFS storage pool to a another host, (no local copy needed), and then "zpool imported" the replica remotely. See: opensolaris.org/os/project/avs/, plus the demos. > > when i work with linux i use partimage to create an image from one > partitino and store it on another. so i can restore it if an error. > partimage do not work with zfs, so i must use the DD command. > i think so: > DD IF=/dev/sda1 OF=/backup/image > can i create an image this way, and restore it the other: > DD IF=/backup/image OF=/dev/sda1 > when i have two partitions with zfs, can i boot from the live cd, > mount one partition to use it as backup target? > or is it possible to create a ext2 partition and use a linux rescue > cd to backup the zfs partition with dd ? > > > This message posted from opensolaris.org > _______________________________________________ > zfs-discuss mailing list > zfs-discuss@opensolaris.org > http://mail.opensolaris.org/mailman/listinfo/zfs-discuss -- Jim Dunham Engineering Manager Storage Platform Software Group Sun Microsystems, Inc. _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
