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DDBoost Replication
Experts,
We're using DD9500 (5.7) with DDBoost only, no CIFS/NFS with NetBackup. I want to know if MTree replication work for an MTREE that's associated with a storage-unit? after all the storage-units are noting but MTrees or does DDBoost based backups support only MFR?
Thanks
James_Ford
30 Posts
0
January 27th, 2017 05:00
Hi naruto,
So in answer to your question - it is possible to replicate an mtree/logical storage unit (LSU) between DDRs using mtree replication however this is not recommended. The main reason for this is that with MFR the backup application is responsible for controlling replication of individual save sets/files between DDRs (even though replication itself takes place directly from DDR -> DDR). As a result:
- MFR allows you to replicate a subset of data stored in a source LSU/mtree depending on the policy e.t.c. associated with each save set - if you use mtree replication you have to replicate *everything*
- MFR allows you to configure different retention periods for save sets on the source and destination DDR - again with mtree replication you can only control retention period on the source DDR and as soon as the save sets are removed from the source they will be removed from the destination (via mtree replication)
- Getting restores working from a destination LSU which has been replicated via mtree replication can be tricky - there is a KB article which discusses this - unfortunately it is internal only however it does document a number of pitfalls which can stop this from working unless configured absolutely 100% correctly
- Finally (and possibly most importantly) with MFR the backup application is responsible for what gets replicated when hence it is aware that a save set has been cloned to a second DDR and can therefore track existence of the replica in its media database (i.e. it immediately knows about the second copy of the file). In some cases if you use mtree replication then the backup application has no knowledge of the replica so before you can restore from it you would need to manually scan volumes on the destination to locate save sets before the restore can even start (which can take considerable time and adds administrative overhead)
Given all of the above I would really recommend MFR over mtree replication unless you have a compelling replication why mtree replication is better for your environment. I hope this helps?
Thanks, James
naruto1
12 Posts
0
January 27th, 2017 12:00
Thanks James you have answered all that I wanted to know. Appreciate your help
Anonymous
5 Practitioner
5 Practitioner
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274.2K Posts
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January 30th, 2017 14:00
Hi Naruto,
Like James said, MFR is recommended for boost. MREPL does work with Boost. However, there are some caveats:
• MTree replication and Managed file replication cannot be used for the same storage unit
• Backup software catalog will not have awareness of replicated copy unlike that with managed file replication
–Backup catalog must be rebuilt on DR site for recoveries from replicated copy
• All backup datasets within a Storage unit (MTree) will be replicated
–With managed file replication, user may choose to not replicate datasets belonging to certain clients, or not replicate the dailies
• The source and replica copy will have the same retention period
–With managed file replication, it is possible to have 30 day retention on source and 90 days on replica
• Replica MTree is read-only
MREPL for Boost benefit:
• Single form of replication for all Ingest protocols
• DD Admin has visibility into amount of data replicated and left to replicate
–Easier to debug performance issues with replication
• No need to have physical connectivity between backup server on primary site and the replica DD system
–Especially useful when replica DD is host by a service provider with strict firewall rules
AnaB1
26 Posts
0
May 18th, 2017 00:00
Hi,
We are using MTree Replication with DDBoost Storage Units.
When you say:
–Backup catalog must be rebuilt on DR site for recoveries from replicated copy
do you mean that you have to scanner the replicated copy to recreate client indexes?
Is not possible to mount the replicated copy in a storage node in the DR site without labeling it and access the replicated data?
Thanks
uvetsi
19 Posts
0
May 18th, 2017 09:00
unlike CIFS and NFS you can not mount a boost storage unit with boost backups for restore purposes. with netbackup for a DR situation a new disk pool will need to be created using the DR DD which has to be similar to the original one (to include the DD name, volume name, disk pool name) and then go through the recovery process which will include syncing the new disk media ID so NetBackup knows where the catalog images resides. and make sure you have a copy of the DR file somewhere.
cheers,
-e