Trying to emulate a larger SSD size about femu HOT 4 CLOSED

Hi,

If your disk image size matches the size in the configuration file, it should be fine.
For the configuration file, the total simulated SSD size can be calculated as
sim_ssd_sz = # of flash-chips * # of blocks per chip * # of pages per block * # of sectors per page * sector size. (assuming # of planes per chip is 1).

Make sure sim_ssd_sz * (1 - OVP) >= 16GB here.

The blackbox FTL you are using is no longer maintained, we created a new FTL specifically designed for FEMU model, checkout the newest commit in master branch. I suggest you use the new one. We will add some documents later.

from femu.

thank you for your quick response.
I decided to multilply the number of blocks per chip by 16 in order to get the size I wanted and checkedout to the lastest commit like you suggested but I still wasn't able to create the larger ssd.

since I've clearly did something wrong i thought it would be best if I'd eleborate on what I've done.
I've created a vssd1.raw file with a size of 16GB using the qemu-img create command and put it in the images dir. I've also changed the BLOCK_NB var in the vssd1.conf file from 16 to 256.
when running the black box script and using the fdisk -l command (from within the femu vm) I could see the sda1 device and the nvme0n1 device but it's size was still 1 GB.
obivously I've misunderstood something in this process and I'd appriciate it if you'll tell me what am I missing here.

also, I didn't quite understand what you meant here:
Make sure sim_ssd_sz * (1 - OVP) >= 16GB here.

thank you so much for your help.

from femu.

Make sure sim_ssd_sz * (1 - OVP) >= 16GB here.

Oh, sorry, you can ignore this part ..

I'm gonna close this issue, just in case u have more questions, feel free to re-open it, thx!

from femu.

What is the relationship between the device size as given in the QEMU command and and the device size as hard-coded into ftl.c? If the passed-in device size is smaller than the hard-coded device size, then is the difference equivalent to overprovisioned device capacity?

A related issue: I set them to the same thing (devsz_mb=2048, which the FEMU OS reports as 2147483648 bytes, and the appropriate settings in ftl.c) and I see the following: RD-ERRRRRRRRRR,start_lpn=524287,end_lpn=524288,tt_pgs=524288. (I also checked the read size and it's 8 sectors.) What is going wrong here---shouldn't the ending LPN wrap around?

from femu.