Raid 0 Slow Read Writes are ok...-

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mirol

Member
Jan 6, 2018
39
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Hi my hardware is
Freenas 11.2
ASRock Rack D1540D4U-2T8R with lsi 3008 flashed to it newest firmware
64 DDR 4 2133 ECC
7x 12TB HGST Sas HDD HUH721212AL5200 (512e)

6 of them in raid 10 got scores of
DD tests
Write
dd if=/dev/zero of=testfile bs=4M count=15000
15000+0 records in
15000+0 records out
62914560000 bytes transferred in 98.526636 secs (638553825 bytes/sec)
Read
dd of=/dev/zero if=testfile bs=4M count=15000
15000+0 records in
15000+0 records out
62914560000 bytes transferred in 181.292199 secs (347034016 bytes/sec)
7 of them in raid 0
root@freenas:/mnt/RAZID0/test3256k # dd if=/dev/zero of=testfile bs=4M count=15000
15000+0 records in
15000+0 records out
62914560000 bytes transferred in 39.182534 secs (1605678710 bytes/sec)
root@freenas:/mnt/RAZID0/test3256k # dd of=/dev/zero if=testfile bs=4M count=15000
15000+0 records in
15000+0 records out
62914560000 bytes transferred in 48.032904 secs (1309822104 bytes/sec)

I dont know why always read is much slower than write i test them as well in 3 mirrors just to make sure non of the hdd are faulty

Thats 1 Mirror
62914560000 bytes transferred in 249.303043 secs (252361781 bytes/sec)
root@freenas:/mnt/M1/test # dd of=/dev/zero if=testfile bs=4M count=15000
15000+0 records in
15000+0 records out
62914560000 bytes transferred in 186.721765 secs (336942830 bytes/sec)
Thats 2 Mirror
root@freenas:/mnt/M2/test # dd if=/dev/zero of=testfile bs=4M count=15000
15000+0 records in
15000+0 records out
62914560000 bytes transferred in 238.096736 secs (264239490 bytes/sec)
root@freenas:/mnt/M2/test # dd of=/dev/zero if=testfile bs=4M count=15000
15000+0 records in
15000+0 records out
62914560000 bytes transferred in 181.861459 secs (345947736 bytes/sec)
Thats 3 Mirror
root@freenas:/mnt/M3/test # dd if=/dev/zero of=testfile bs=4M count=15000
15000+0 records in
15000+0 records out
62914560000 bytes transferred in 258.467904 secs (243413433 bytes/sec)
root@freenas:/mnt/M3/test # dd of=/dev/zero if=testfile bs=4M count=15000
15000+0 records in
15000+0 records out
62914560000 bytes transferred in 195.182976 secs (322336308 bytes/sec)

I try loads of different things change block size helps a bit but but not much it seams everything above 2 drivers raid start getting lower reads compare to writes.Any idea what could cause it....