perfSONAR User Q&A and Other Discussion

[Hyojoon Kim <>]

This is a very good point. Thank you for this insight in terms of the lifespan of the product. 

We transfer all measurement results to our measurement archive, so storage size itself is not a big issue. But it’s good to know that larger eMMC size will also result in longer lifespan.

Thanks! 

-Joon 

On Dec 9, 2015, at 11:52 AM, Mark Feit <> wrote:

Daniel Doyle writes:

The 4G model might be more futureproof (and I think it comes with more disk space, which might be relevant if you're doing more)…

It does come with twice as much (64 GB vs. 32), and I can add some additional food for thought:

The one wear item in a LIVA is the eMMC.  All other things being equal and assuming some other part of the system isn’t prone to dying first, how long it takes the wear leveler in the eMMC to exhaust all of the cells will determine the lifespan of the entire unit.  The component isn’t field-replaceable, so once it’s had it, that’s the end.

The toolkit installation occupies about 2 GB, leaving 30 GB of room for wear on the smaller eMMC and 62 GB on the larger one, or more than twice as much flash to bear the brunt of the writes.  That, combined with the fact that additional RAM will allow for more disk buffer, will put even less wear on it because the kernel will be less inclined to preemptively write process pages out to swap.  You may end up getting a lot more life out of the bigger unit because of it.

Anyway, the $40 additional for the 4/64 GB version is a 19% premium over the 2/32 GB version.  If the unit lasts 19% longer, you will have recouped that money.  20% longer or more and you’re ahead of the game cost-wise and can delay having to fund new ones.

—Mark