exfat on sd

root@macchiatobin:/tmp/sd# fio --name=random-write --ioengine=io_uring --rw=randwrite --bs=4k --numjobs=1 --size=4g --iodepth=1 --runtime=60 --time_based --end_fsync=1
random-write: (g=0): rw=randwrite, bs=(R) 4096B-4096B, (W) 4096B-4096B, (T) 4096B-4096B, ioengine=io_uring, iodepth=1
fio-3.21
Starting 1 process
random-write: Laying out IO file (1 file / 4096MiB)
Jobs: 1 (f=1): [F(1)][100.0%][eta 00m:00s]
random-write: (groupid=0, jobs=1): err= 0: pid=9030: Mon Dec  7 00:28:17 2020
  write: IOPS=1575, BW=6300KiB/s (6451kB/s)(2886MiB/469160msec); 0 zone resets
    slat (nsec): min=2200, max=139400, avg=3934.44, stdev=537.85
    clat (nsec): min=400, max=50627k, avg=75497.02, stdev=1163719.21
     lat (usec): min=11, max=50630, avg=79.66, stdev=1163.72
    clat percentiles (usec):
     |  1.00th=[   12],  5.00th=[   12], 10.00th=[   13], 20.00th=[   13],
     | 30.00th=[   14], 40.00th=[   14], 50.00th=[   14], 60.00th=[   14],
     | 70.00th=[   15], 80.00th=[   15], 90.00th=[   15], 95.00th=[   17],
     | 99.00th=[   21], 99.50th=[   25], 99.90th=[19530], 99.95th=[28705],
     | 99.99th=[28967]
   bw (  KiB/s): min= 6400, max=223344, per=100.00%, avg=49614.25, stdev=75935.67, samples=119
   iops        : min= 1600, max=55836, avg=12403.60, stdev=18983.99, samples=119
  lat (nsec)   : 500=0.01%, 750=0.01%, 1000=0.01%
  lat (usec)   : 2=0.01%, 10=0.01%, 20=98.66%, 50=1.00%, 100=0.01%
  lat (usec)   : 250=0.02%
  lat (msec)   : 2=0.01%, 4=0.01%, 20=0.23%, 50=0.07%, 100=0.01%
  cpu          : usr=0.62%, sys=0.98%, ctx=739221, majf=0, minf=30
  IO depths    : 1=100.0%, 2=0.0%, 4=0.0%, 8=0.0%, 16=0.0%, 32=0.0%, >=64=0.0%
     submit    : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
     complete  : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
     issued rwts: total=0,738943,0,0 short=0,0,0,0 dropped=0,0,0,0
     latency   : target=0, window=0, percentile=100.00%, depth=1

Run status group 0 (all jobs):
  WRITE: bw=6300KiB/s (6451kB/s), 6300KiB/s-6300KiB/s (6451kB/s-6451kB/s), io=2886MiB (3027MB), run=469160-469160msec

Disk stats (read/write):
  mmcblk1: ios=0/170161, merge=0/3517, ticks=0/27894249, in_queue=27894249, util=98.89%