[SPDK] Bad Sectors / expected 'error' responses & timing

Hello SPDK team,

First, thank you for the really cool work you are doing!  I am working on a small satellite mission at MIT, which will use a 6-channel SDR (SW defined radio). My task is to ensure that the 6-channel SDR data is saved reliably to an SSD. I am working on the processor (PS) side. Another colleague is working on the FPGA PL (programmable logic) side. The FPGA will provide DMA (still under development).

My general idea to try to achieve zero-copy performance is:

 ADC -> PL Queue
   PS Determines SDRAM temporary storage
 DMA from PL Quque -> SDRAM  (likely using libiio)
  PS Determines when a block (or other storage unit, TBD) is ready to go to SSD
   -> because our data is always the same size/format, I believe we can use an analytic/deterministic equation to determine the storage location
 DMA from SDRAM -> SSD (likely using SPDK)

when its time to 'process' the data (which has to be at a later time due to power limits of the satellite):

 PS determines (analytic equation) data to be processed
 DMA from SSD -> SDRAM (w SPDK)
 PS informs PL of data vailable
 PL processes data via DMA
 PL informs new 'processed data queue' ready
 PS prepares location for processed data
 DMA from SDRAM -> SSD (w SPDK)

The mission PI (principal investigator) has one main worry of our approach: he is concerned that SSD's can end up with 'bad sectors', like older drives, but that its usually a big chunk of space that goes bad. We are not concerned about single-event-upsets (when just one individual piece of data gets damaged), but rather when a large section that can result in us loosing too much data.

I understand that the idea of keeping track of 'bad sectors' in 'hard drives' is usually the task of a file-system. However, for our purposes a file system is appearing to be too much overhead and we have not found one that would help us with a 'zero copy' setup. But we need to be able to know when there are data errors (read data is garbage) and not slow down if there is a bad write request (if a bad write slows down the system, then we loose 'new' data that should have been saved).

I read the documentation as much as possible, and did a good amount of online searching for the 'expected' response from SPDK when the SSD has errors. But I could not find any information on that. I would greatly appreciate if anyone in the team can guide me in the right direction (maybe its pointing to some standard that SPDK adheres to [NVMe & PCIe] but even that I was not sure how SPDK returns such errors and the expected timing of them).

Hopefully this was clear and its in the scope of this list; if its not, please ask me to clarify or I greatly appreciate if you point me in the right direction.

Thank you!

Alvar

PS, Summary:
- Trying to do zero-copy 6-channel data saving from FPGA to SSD (PCIe NVME)
- If I don't want a full file-system, how can I handle 'bad sector' type errors in the SSD?
- Is there any spec of expectation on the timing impacts when an error occurs?