Maximum Write operation on sbRIO-9601 (128 Mb non-volatile storage)

[D.S]

I am using sbRIO-9601, having 128 Mb non-volatile storage.

In my application, I need to write binary files and save it into sbRIO memory.

As we all know flash memory has limited number of write operation.

My question is that, how many times I can write/re-write a particular memory sector of sbRIO?

I am not concern about storage size, because logically I am flushing old data. I am only concern about about, how many number of times I can write a particular memory sector.

[Spex]

Hi Deepak,

The DiskOnChip Flash storage chip on Single-Board RIO utilizes automatic wear-leveling that distibutes file writes physically across the disk to evenly wear out sectors.  Because of the wear leveling, it is impossible to know which sector your LabVIEW file is being written to for any specific write operation.  Wear-leveling significantly increases the lifetime of the overall flash drive capacity, but makes it difficult to predict the drive lifespan without characterizing a specific application and its disk usage.

We have written a whitepaper outlining best practices for long-term disk storage applications and it is posted on ni.com here: 

Understanding and Extending the Life of my Solid-State Drive

The SSD block size for the 128MB and 256MB disks is 16KB, so writing to the disk in 16KB increments will also improve the longevity of the disk.

Regards,

[D.S]

Thanks Spex,

According to data provided by you, there are 8192 memory sectors of 16 Kb each (if I calculated correctly).

Now if my application writes 16 Kb of data every second (very strictly), what could be the lifespan of sbRIO-9601 (128 Mb).

Please be specific. We need to commit to our customer.

[Spex]

Hi Deepak,

Please give me some time to investigate if this is enough information to determine disk life expectancy.

In the mean time, writing 16kB to disk every second is very heavy disk utilization.  That comes out to ~1.35GB of data written to a 128kB disk every day.  Even if the disk were completely free (no operating system, drivers, and code) the disk would only be able to hold about the latest 2 hours of data.  The disk is more intended for long term data storage.  Off hand, I would not recommend using the disk as you have proposed and I would recommend re-factoring your application to write to the disk less often.

Regards,

[Spex]

Hi Deepak,

Can I ask why you need to log so much data to disk? 

Thanks,

[Spex]

Hi Deepak,

Can I ask why you need to log so much data to disk? 

Thanks,

[D.S]

Hello Spex

I am working on GPRS based data logging applications, in which sbRIO has to work as a standalone RTU. Whenever there is no GPRS connectivity, we need to log data locally on sbRIO. Whenever GPRS becomes healthy, we will send all measurements to the central server. We need to fix our sbRIO in many remote areas where 100% GPRS connectivity is not guaranteed.

There is not any local PC connected to sbRIO. SO may be we need to store data on sbRIO for upto 2-5 Days.

Pls try to provide some solution within sbRIO, we cannot afford external memory connected to sbRIO. 

[Spex]

Hi Deepak,

I think I am missing something.  You said you may need to log continuous data for up to 5 days at a time and then upload it to a server when the connection resumes.  Because of the limited size of the disk, you will only have room for a few hours of data at 16kB per second logging rate.  To really achieve 5 days of continuous logging on a 128MB disk, you would need to reduce your rate to well below 16kB per Minute.

Do you expect that any of your deployed systems will continuously be required to log data 5 days at a time or is the logging feature just a backup for when the connection is down?

I'm still working with the development team on your technical questions, but I want to be able to give them every detail I can.

Regards,

[D.S]

Thanks for your response,

Obviously I will not log data in every second, this is just a simulation for counting life span of the disk.

Earlier I mentioned, we are not worried about the size of data, we are only worried about maximum write operation we can perform.

If customer ask for XYZ years support for sbRIO, we must have a datasheet on the basis we can assure him for support.

[D.S]

Hi Spex...

Waiting for your reply...