# flashbench and erase block size of ssd

## unknown2

has anyone use flashbench before?

i am trying to determine the erase block size of my old intel x25-e ssd, but the result of flashbench is quite confusing

Can anyone helps?

https://github.com/bradfa/flashbench

#read test

$ sudo flashbench -a /dev/sdb1 --blocksize=1024

align 8589934592	pre 89.9µs	on 79.3µs	post 90.4µs	diff -10811n

align 4294967296	pre 90.4µs	on 85µs	post 90.4µs	diff -5373ns

align 2147483648	pre 89.9µs	on 77.6µs	post 90.5µs	diff -12604n

align 1073741824	pre 90µs	on 77.5µs	post 90µs	diff -12447n

align 536870912	pre 90.4µs	on 78.2µs	post 90.1µs	diff -12052n

align 268435456	pre 90.2µs	on 88.2µs	post 90.4µs	diff -2131ns

align 134217728	pre 90.3µs	on 77.7µs	post 90µs	diff -12420n

align 67108864	pre 89.7µs	on 77.1µs	post 89.8µs	diff -12656n

align 33554432	pre 90.2µs	on 77.1µs	post 90.2µs	diff -13081n

align 16777216	pre 90.4µs	on 77.7µs	post 90µs	diff -12507n

align 8388608	pre 90.4µs	on 77.3µs	post 90.5µs	diff -13151n

align 4194304	pre 90.6µs	on 77.8µs	post 90.3µs	diff -12637n

align 2097152	pre 90.3µs	on 77.8µs	post 90.3µs	diff -12535n

align 1048576	pre 90.1µs	on 77.7µs	post 90µs	diff -12363n

align 524288	pre 90.5µs	on 77.7µs	post 90.4µs	diff -12774n

align 262144	pre 90.1µs	on 77.3µs	post 90.2µs	diff -12845n

align 131072	pre 90.4µs	on 78.4µs	post 90.6µs	diff -12132n

align 65536	pre 90.3µs	on 77.8µs	post 90.1µs	diff -12379n

align 32768	pre 90µs	on 77.1µs	post 90.1µs	diff -12921n

align 16384	pre 90.3µs	on 77.4µs	post 90.2µs	diff -12832n

align 8192	pre 90.2µs	on 84.7µs	post 90.3µs	diff -5525ns

align 4096	pre 90.3µs	on 77.5µs	post 90.1µs	diff -12642n

align 2048	pre 90.2µs	on 90.3µs	post 88.6µs	diff 855ns

#first trial of write test

$ sudo flashbench -O --erasesize=$[64 * 1024 * 1024] --blocksize=$[256 * 1024] /dev/sdb1  --open-au-nr=2 --random

64MiB   177M/s  

32MiB   175M/s  

16MiB   202M/s  

8MiB    154M/s  

4MiB    112M/s  

2MiB    109M/s  

1MiB    102M/s  

512KiB  85.1M/s 

256KiB  69.7M/s 

#second trial of write test

$ sudo flashbench -O --erasesize=$[64 * 1024 * 1024] --blocksize=$[256 * 1024] /dev/sdb1  --open-au-nr=2 --random

64MiB   205M/s  

32MiB   185M/s  

16MiB   174M/s  

8MiB    164M/s  

4MiB    111M/s  

2MiB    110M/s  

1MiB    98.8M/s 

512KiB  84.3M/s 

256KiB  70.1M/s

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