Introduction to Synthetic full backup for NetWorker 8

Question

Introduction to Synthetic full backup for NetWorker 8 Share: Please click here for all contents shared by us. Introduction NetWorker 8 is now a mainstream backup software. Let's look at this article that will introduce a new backup method in NetWorker 8 - Synthetic full backup. Detailed Information In NetWorker 8, a new backup level - Synthetic full is introduced. Literally, Synthetic full backup is a kind of full backup that combines backups. Just as the name implies, Synthetic full backup is different from a full backup. It is a full backup combined with multiple backups. Before talking about Synthetic full backup, let’s look back to a backup level in NetWorker 7.6 - Consolidate. Consolidate backup is also a kind of backup that combines backups. It performs level 1 backup for a save set first and then combines the latest full backup of the save set with this level 1 backup into a consolidate backup. Same as Consolidate backup, Synthetic full backup can save bandwidth and realize faster recovery. The backup level - Consolidate no longer exists in NetWorker 8. NetWorker 8 has launched a backup level which is similar to Consolidate called Synthetic full. Synthetic full backup combines full backup with all subsequent incremental backups into a new full backup -- Synthetic full backup. When a second Synthetic full backup is performed, it will combine the previous Synthetic full backup with all subsequent incremental backups. Synthetic full backup has two kinds of backup levels: • synth_full - performs synthetic full backup and combines the latest full backup with all subsequent incremental backups into a new full backup. • incr_synth_full - performs a new incremental backup and then generate synthetic full backup immediately. This can ensure the status of the save set is up-to-date. To better understand synth_full and incr_synth_full, I’d like to explain more. synth_full can only back up the status of save set the last time when performing incremental backup. If any change is made after the latest incremental backup, synth_full will not back up it. In order to back up the latest status of save set, you should choose incr_synth_full. It will perform an incremental backup on the basis of the latest incremental backup and then combine the incremental backup with the latest full backup and all subsequent incremental backups. For example, we perform a full backup on Sunday 9:00 am and perform incremental backups on Monday, Tuesday and Wednesday 9:00 am. If we perform synth_full on Wednesday 2:00 pm, it will combine the full backup of Sunday with three subsequent incremental backups into a Synthetic full backup. The status of save set is its status on Wednesday 9:00 am. If the save set was modified on Wednesday 1:00 pm, synth_full will not back up its status at that time. However, if we perform incr_synth_full, it will perform an incremental backup to back up the current status (Wednesday 2:00 pm) first and then combine this incremental backup with the full backup of Sunday and three subsequent incremental backups into a Synthetic full backup. This ensures the status of save set is latest when performing a synthetic full backup. Author: Tim Quan

ble1 · Answer

What backup types are supported with this method?

ECN-APJ · Answer

Hi Hrvoje, sorry for the late response since we are in APJ time zone.

Synthetic full backup combines full backup with all subsequent incremental backups into a new full backup -- Synthetic full backup. So it is a combination of full backup and incremental backups. I am not sure whether this answers your question. If not, please feel free to let us know.

Thanks very much.

ble1 · Answer

Question was about backup type - I assume this only can work with file system backups, right?  Does this cover also NDMP based backups?  What about file system backups done with PowerSnap/NSM?  I understand you can't merge snapshots, but copy of snapshot which would written on let's say DD you could merge as in theory there is difference between rolled over save set and regular one - is that supported?

ERic18 · Answer

Yes, it's correct. The limitation of the the (virtual) synthectic full

Do not perform a synthetic full backup, if the:

◆ Backup type is VSS.

◆ Backup type is NDMP, SCSI or VCB.

◆ Save set belongs to a snapshot group.

◆ Save sets contain backups of raw disk file partitions.

◆ Save sets contain database systems such as Microsoft Exchange and Oracle.

◆ Backup command with save is not used.

◆ For UNIX clients, include the forward slash to designate root "/" when specifying a

save set name. Otherwise, the synthetic full backup will fail. For example, if /tmp is

misspelled as tmp in the save set list of the Client resource, the backup will fail.

Synthetic full backups 81

Backing Up Data

◆ For Windows clients, include the backslash “\” when specifying a drive letter in a save set

name. Otherwise, the synthetic full backup will fail. For example, if D: is typed in the save set

list of the Client resource, instead of D:\, the synthetic full backup will fail.

ECN-APJ · Answer

Hi Hrvoje, yes, we are clear now. Eric is the expert we invited from support team to answer this. Hope his answer helps.Have a good day.

OscarBackup · Answer

That´s Greath!!!

Yuanyi · Answer

Is there any way to identify whether the save set is full backup or synthetic full backup via GUI or command line?

ble1 · Answer

I didn't check as I do not run 8.1, but I assume level field in mminfo should show it.

ble1 · Answer

According to manual (mminfo), you can do something like mminfo -q syntheticfull -r ssid,name

Yuanyi · Answer

I have already used mminfo, it seems level field is always full for both full backup and synthentic full backup.

ble1 · Answer

If you do mminfo -q ssid= -S does that give you any information about SSID being synth_full?

CarlosRojas · Answer

Hi Tim, I didn't find anything related to the required configuration on Data Domain side. Don't we need to enable that option as well on DD? Thank you, Carlos

ble1 · Answer

Isn't that you need to have DDOS 5.4 or higher and that's it?

ECN-APJ · Answer

Hi Yuanyi,

Synthetic full: We can set that in the schedule policy. It is the same as normal level backup( incr, full) however in 8.1 we can only set incr+synthetic full (same as synthetic full)

For virtual synthetic full: there is a check box in the right corner of the general tab in client properties.

In command line, you can set level by using syntax “-l” when using savegrp command. For the details, please kindly help to check NetWorker Command Reference Guide. The syntax “-l” can also be combined with other syntax too.

Hope that helps.

ECN-APJ · Answer

Hi Carlos, we confirmed that we need DD OS version 5.3 and above. synthetics full is enabled by default in DD. So we don't need special configuration on DD side. We just setup from the NW side to perform the synthetic full level backup.

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