Write performance ZFS

Quick test to measure write performance off two ZFS pools using Raid2z on Linux

Hardware for testbench

Both SAS Cables are connected to SAS Expander for a Total of 12 Gbit/s

ZFS Pool 1

ZFS pool consists of 10 drives in an Raid2z configuration. all drives are 7200rpms. Toshiba has 128MB of cache, Seagate has 256MB of cache.

5x Toshiba N300 8TB(P/N HDWN180UZSVA)
5x Seagate Ironwolf 8TB (P/N ST8000VN0022)

dd if=/dev/zero of=testFile.img bs=1G count=8 oflag=dsync

Average speed after 10 tests was 781 MB/s

dd if=/dev/urandom of=/dev/shm/testFile.img bs=32M count=128 oflag=dsync
dd if=/dev/shm/testFile.img of=testFile.img bs=4G count=1 oflag=dsync

Average speed after ten tests of copying file from memory was 651 MB/s

ZFS Pool 2

ZFS pool consists of 10 drives in an Raid2z configuration. Western Digitals drives are only 5400 RPM and has a lower rated transfer speed of 175 MB/s compared to Seagate/Toshibas 200+

5x Seagate Ironwolf 8TB (P/N ST8000VN0022)
5x WD Red 8TB (P/N WD80EFZX)

dd if=/dev/zero of=testFile.img bs=1G count=8 oflag=dsync

Average speed after 10 tests was 605 MB/s

dd if=/dev/urandom of=/dev/shm/testFile.img bs=32M count=128 oflag=dsync
dd if=/dev/shm/testFile.img of=testFile.img bs=4G count=1 oflag=dsync

Average speed after ten tests of copying file from memory was 518 MB/s

Conclusion

Western Digitals 5400 RPM Drives slows down transfer rate with about 20% compared to Seagate and Toshibas 7200 RPM Drives. mathematically 5400 RPM is approximately 20% lower than 7200 RPM

5400 / 7200 =~ 0,8
605 / 781 =~ 0,8
518 / 651 =~ 0,8