ZFS Command Improvements and Changes

The following section describes recent improvements and changes to the ZFS command interface in the Solaris Express release.

• Clearing device errors – You can use the zpool clear command to clear error counts associated with a device or the pool. Previously, error counts were cleared when a device in a pool was brought online with the zpool online command.

• Compact NFSv4 ACL format – Three NFSv4 ACL formats are available: verbose, positional, and compact. The new compact and positional ACL formats are available to set and display ACLs. You can use the chmod command to set all 3 ACL formats. Use the ls -V command to display compact and positional ACL formats and the ls -v command to display verbose ACL formats.

• Double Parity RAID-Z (raidz2) – A replicated RAID-Z configuration can now have either single- or double-parity, which means that one or two device failures can be sustained respectively, without any data loss. You can specify the raidz2 keyword for a double-parity RAID-Z configuration. Or, you can specify the raidz or raidz1 keyword for a single-parity RAID-Z configuration.

• Hot spares for ZFS storage pool devices – The ZFS hot spares feature enables you to identify disks that could be used to replace a failed or faulted device in one or more storage pools. Designating a device as a hot spare means that if an active device in the pool fails, the hot spare automatically replaces the failed device. Or, you can manually replace a device in a storage pool with a hot spare.

• Replacing a ZFS File System With a ZFS Clone (zfs promote) – The zfs promote command enables you to replace an existing ZFS file system with a clone of that file system. This feature is helpful when you want to run tests on an alternative version of a file system and then, make that alternative version of the file system the active file system.

• Recovering destroyed pools – The zpool import -D command enables you to recover pools that were previously destroyed with the zpool destroy command.

• Temporarily take a device offline – You can use the zpool offline -t command to take a device offline temporarily. When the system is rebooted, the device is automatically returned to the ONLINE state.

• Upgrading ZFS Storage Pools (zpool upgrade) – You can upgrade your storage pools to a newer version to take advantage of the latest features by using the zpool upgrade command. In addition, the zpool status command has been modified to notify you when your pools are running older versions.

• ZFS backup and restore commands are renamed – The zfs backup and zfs restore commands are renamed to zfs send and zfs receive to more accurately describe their function. The function of these commands is to save and restore ZFS data stream representations.

• ZFS and zones improvements – On a Solaris system with zones installed, you can use the zoneadm clone feature to copy the data from an existing source ZFS zonepath to a target ZFS zonepath on your system. You cannot use the ZFS clone feature to clone the non-global zone. You must use the zoneadm clone command. For more information, see System Administration Guide: Virtualization Using the Solaris Operating System.

• ZFS is integrated with Fault Manager – A ZFS diagnostic engine is included that is capable of diagnosing and reporting pool failures and device failures. Checksum, I/O, and device errors associated with pool or device failures are also reported. Diagnostic error information is written to the console and the /var/adm/messages file. In addition, detailed information about recovering from a reported error can be displayed by using the zpool status command.

For more information about these improvements and changes, see the Solaris ZFS Administration Guide.