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NDMP-backup limited to 1 stream per filesystem ?

Jaap_Hartog
Level 4

Dear community,

 

we are running NDMP-backups from an EMC-NAS.
Some policies contain singular directives in the Backup Selections:
set snapsure=y
/root_vdm_1/fs_homes/Homes

These are the policies for the big filesystems that consume quite a lot of time.
The applied Storage Unit in this case has got for  Maximum concurrent write drives the value of 4. (As we have 4 drives).

At the end of last weekend I observed that the 3 largest (remaining) policies were running parallell, but  using only1 drive per policy, thus leaving 1 drive unused.

Especially with backing up the large filesystems we barely make it through the weekend and we would like to use as many drives as possible.

Is this a standard behaviour for backing up singular filesystems with NDMP, as I am used to see with non-NDMP backups that the drives in such a case are all in use and the load is spread over the drives ?

 

Thanks in advance for the answers !

 

Kind regards,

Jaap Hartog

1 ACCEPTED SOLUTION

Accepted Solutions

Jim-90
Level 6

We have the same problem, One huge volume with 80-90 million files.  Everybody says we can live with it taking days to backup.  I did think about actually mapping it and taking a backup of it using  a MS-Windows policy + Accelerator .....something you may want to consider.  

I think there's an accelerator option or something similar for NDMP in NBU 7.7

 

 

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6 REPLIES 6

RamNagalla
Moderator
Moderator
Partner    VIP    Certified

Does this big filesystems policy is enabled with Mulitstreaming.. if it does not it will only trigger one job for all 4 file systems and use one Drive...

if it selected with Mulitstreaming and also  Schedules enabled with Muitiplexing.. , even then it will select 1 drive (based on the mulitplexing value in storage unit and Schedule)and use only one Drive to optimize the Drive usage.

if you would like to use all the Drives for the policy, enable Mulitstreaming in policy attributes and disable mulitplexing in the policy Scheudle.

Do remember.. if you do this..all other policies using the same storage unit will be in Queue statate untill the big filesystems backups are compleated since all 4 avaliable drives are being used by big filesystems policy and result status code 196 failrues.

so plan your Drive capacity and requirement and based on that do the modifications.

Jaap_Hartog
Level 4

I have attached some screendumps to provide  more clarity about the used settings:

policy.jpg

schedule.jpg

Storage_unit.jpg

As you can see, all is (and was already) configured the way you stated.

Media Multiplexing in the Schedule is set to 1, thus effectively switching it off.

Any further idea's ?

 

RamNagalla
Moderator
Moderator
Partner    VIP    Certified

one more place to verify is backup selection 

you were saying 3 largest (remaining) policies, so what are the backup selection for those 3 policies..?

do they have only one backup selection in each? , if yes they will definatly use 3 Drives since it can only trigger only 3 jobs..

if this is the case and you would like to use 4th Drive as well, you need to split the backup selection for one of the largest polices and make the backup selections as 4 together, then it will start using 4 drives.

 

 

Jaap_Hartog
Level 4

The largest remaining policies do have only 1 backup selection in each.
The selection points towards the mountpoint of each filessystem.
One policies can't bve split up at all and the other two consist of user-directories.

Taking the policies down to the level of the user-directories would mean a lot of administration and a guarantee of missing out on the backup of somebody's userdirectory.

An alternative would be to create extra filesystems and spread the userdirectories over these filesystems, so that the total amount per filesystem is smaller than before.

But I am not the administrator of our NAS ....
 

RamNagalla
Moderator
Moderator
Partner    VIP    Certified

agreed... but i dont think you any other options than you stated above..

Jim-90
Level 6

We have the same problem, One huge volume with 80-90 million files.  Everybody says we can live with it taking days to backup.  I did think about actually mapping it and taking a backup of it using  a MS-Windows policy + Accelerator .....something you may want to consider.  

I think there's an accelerator option or something similar for NDMP in NBU 7.7