Below are some questions, along with Answers regarding SM2T Block Sizes... that a customer had after looking at the SM2T Documentation... that may help clear things up, as they did for a previous customer.
1. The SM2T doc’s state that you can up the block size from 240 Kb to 256 Kb, as I read it… it’s just saying you “can”, not that you have to or that it’s recommended either way… am I correct in how I read this??
Answer - SM2T Backups require a minimum 240 Kb block size. The 256 kb block size support was added by NetApp in DataOntap 8.x as requested by another customer. So yes you can use either 240 kb or 256kb.
2. The SM2T doc’s also state that you have to do this on the devices, which as I understand it… only needs to be done to for devices directly connected to the filer and that are doing SM2T backups… not to devices that will “not be doing SM2T backups”… am I correct on this??
Answer - SM2T Backups will need to target devices configured using either 240kb or 256kb block sizes. These can be direct or indirect backups. Non-SM2T backups may also use the larger device block sizes, but not required.
3. Does any configuration change, on the actual filer, need to be done… to accommodate the change from the default of 240 Kb to the 256 Kb?? (outside of the /netvault/config/ndmpsmtversions.cfg file??)
Answer - No configuration changes need to be done on the filer
This should hopefully answer any questions and concerns, and clear up any confusion.