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The SSD controller triggers the garbage collection routines on a specific ship or block when a certain threshold of either invalid pages or written pages is met, based on the GC policy (my guess is that most SSDs use the greedy policy).

I am trying to measure the impact of some workloads on a specific SSD, I've already done the performance measurements using FIO, but i would like to go even further.

Is there a way to get notified when the Garbage Collector routine on a SSD is triggered?

SamTh3D3v
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  • If this is a NVMe SSD the nvme-cli has some extended statistics on usage wear and fill, but not really much on GC http://feed.askmaclean.com/archives/using-nvme-command-line-tools-to-check-nvme-flash-health.html – eckes May 20 '17 at 23:53

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No, what you are asking is basically the "secret sauce" of your SSD controller firmware. SSD vendors treat the internal controller routines, and their implementation, as a trade secret.

You can only guess at what is happening by triggering a specific load and carefully examine the results.

shodanshok
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