Question

limiting streams not per datastore but array

  • 13 June 2023
  • 2 replies
  • 47 views

Userlevel 2
Badge +7

Hi guys, I am struggling to find a balance between stream and datastore limits for our environment which has many datastores and clusters on a shared flash array (using SAN transport). The VSA client also contains numerous remote sites all backing over over NBD, all of which funnel to the same MA/access node. The MA has plenty of resources but is fast enough to really hammer the array.

https://documentation.commvault.com/11.21/expert/31115_performance_tuning_for_backups.html is what I’m referencing but I see no clear cut way to throttle TOTAL datastore streams hitting the SAN but not limit all the various NBD-based remote subclients. Meaning - I can’t limit the streams of the MA without impacting the run times of all those NBD clients because they take hours to complete in some cases. Basically what I’m looking for is a way to have the proxy/access node tell “hey, all these subclients and datastores reside on the same array, so limit total streams for all those combined SAN streams to say 10” without slowing down the non-SAN based transport jobs. Is this possible?

I’d prefer to not have to create lots of plans to split things out 30 different ways but this seems like the only way (like I used to do pre-plan days).

thanks


2 replies

Userlevel 6
Badge +13

I’m not aware of any way to do that currently, but that sounds like a valid Customer Modification Request. If you open a Support ticket and it’s not a current feature, Support can submit a CMR for Development to see if this would be a feasible request. 

Userlevel 2
Badge +7

Ok, I will do that. I would imagine that this info can be derived from the datastores and mapping to SC’s or content, particularly when doing SAN transport or hotadd I suppose. I had thought about reducing the readers for every SC (more or less we do 1-2 datastores per SC to avoid a single SC with 100’s or even 1000’s of VMs in it), that still doesn’t work if the array has 20 datastores, that’s still 20 streams and more than enough to crush the SAN. What are other people doing other than splitting things out into different schedules or plans to schedule them in a staggered way without hamstringing the slower NBD or remote hypervisor backups under the same VSA client? 

thanks

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