With AdvancedCopy Manager, the following methods are supported for ZFS backup and restoration.
Select them according to your particular backup purpose.
Online backup using the ZFS Snapshot function (hereafter referred to as "ZFS Snapshot")
Offline backup using the export and import functions of ZFS (system stop or disconnection of storage pool)
Online backup
This backup method uses ZFS Snapshot.
Backups are performed by combining ZFS Snapshot with the zfs send and zfs receive commands. With consideration for the effects on transactions, we recommend that you implement a combination of periodical (e.g. daily) differential backups with full backups at constant intervals (weekly or monthly).
Using ZFS Snapshot, backups can even be performed while the ZFS file system is operating, but it is necessary to ensure the consistency of data in each operation when backing up or restoring them. Since there are different ways to ensure consistency, depending on your applications and types of data (DB etc.), you have to investigate them for each type of operation.
Differences as compared to conventional (UFS) backup
Online backup of ZFS uses the zfs send and zfs receive commands to back up the data captured by the snapshot onto the backup server. Therefore, compared to UFS backup, it has characteristics as stated below. If you require online backup, according to your operating requirements, you should also consider using UFS.
Depending on the amount of backup data, processing takes more time.
Depending on the amount of backup data, a higher burden is placed on CPUs and disks (and on the network, if you back up onto another server).
Note
Online backup of the system area is not supported. For the system area, perform offline backup.
Point
Since differential backup processes only the portions that are different from the previous snapshot, the backup amount depends on the amount of updated data.
Differential backups are backed up to the same backup storage pools as full backups. In the event of failure of a physical disk that constitutes a backup storage pool, all differential backups in the same backup storage pool will be affected. Therefore, we recommend you to implement full backups periodically.
This method backs up entire snapshots. It is implemented for the first-time backup and for backups at constant intervals (weekly or monthly).
This method backs up only the updated data that are different from the previous differential or full backup.
Offline backup
This backup method uses the export and import functions of ZFS storage pools.
In order to maintain consistency of storage pools, you should implement backups and restorations with AdvancedCopy Manager offline. Depending on the purpose (system area or data area) of the ZFS storage pool to be backed up, implement the following measures:
For backup sources in the system area
Stop the backup source servers before you start backup or restoration.
For details on backup and restoration procedures, refer to "Backup and restoration of system areas".
For backup sources in the data area
Disconnect the storage pools before you start backup or restoration.
For details on backup and restoration procedures, refer to "Backup and restoration of data areas".
Note
AdvancedCopy Manager is controlled in units of devices constituting a ZFS storage pool. In order to maintain consistency as a ZFS storage pool, control all devices in the storage pool synchronously.
