Frustrated with write performance

[Chris Moore]

For your consideration, another pool layout that I use. Note the logs. This is what we call a Separate ZFS Intent Log (SLOG) and like @Elliot Dierksen said, it is what makes the difference in performance.

Code:

  pool: iSCSI
 state: ONLINE
  scan: scrub repaired 0 in 0 days 00:08:43 with 0 errors on Wed Jun 27 00:08:44 2018
config:

		NAME											STATE	 READ WRITE CKSUM
		iSCSI										   ONLINE	   0	 0	 0
		  mirror-0									  ONLINE	   0	 0	 0
			gptid/a1ae863b-2a0a-11e8-bbf6-002590aecc79  ONLINE	   0	 0	 0
			gptid/a41c596b-2a0a-11e8-bbf6-002590aecc79  ONLINE	   0	 0	 0
		  mirror-2									  ONLINE	   0	 0	 0
			gptid/0243b38d-2a0b-11e8-bbf6-002590aecc79  ONLINE	   0	 0	 0
			gptid/05e0a0d6-2a0b-11e8-bbf6-002590aecc79  ONLINE	   0	 0	 0
		  mirror-3									  ONLINE	   0	 0	 0
			gptid/0ca57011-2a0b-11e8-bbf6-002590aecc79  ONLINE	   0	 0	 0
			gptid/0dce1e70-2a0b-11e8-bbf6-002590aecc79  ONLINE	   0	 0	 0
		  mirror-4									  ONLINE	   0	 0	 0
			gptid/11269a55-2a0b-11e8-bbf6-002590aecc79  ONLINE	   0	 0	 0
			gptid/1237afc0-2a0b-11e8-bbf6-002590aecc79  ONLINE	   0	 0	 0
		  mirror-5									  ONLINE	   0	 0	 0
			gptid/70a040a4-5163-11e8-a76f-0cc47a9cd5a4  ONLINE	   0	 0	 0
			gptid/194a8867-2a0b-11e8-bbf6-002590aecc79  ONLINE	   0	 0	 0
		  mirror-6									  ONLINE	   0	 0	 0
			gptid/1ee68b6a-2a0b-11e8-bbf6-002590aecc79  ONLINE	   0	 0	 0
			gptid/229c431a-2a0b-11e8-bbf6-002590aecc79  ONLINE	   0	 0	 0
		  mirror-7									  ONLINE	   0	 0	 0
			gptid/25ec5bdf-2a0b-11e8-bbf6-002590aecc79  ONLINE	   0	 0	 0
			gptid/275c216f-2a0b-11e8-bbf6-002590aecc79  ONLINE	   0	 0	 0
		  mirror-8									  ONLINE	   0	 0	 0
			gptid/a9cd1b9f-2af2-11e8-8661-002590aecc79  ONLINE	   0	 0	 0
			gptid/ab1dbee6-2af2-11e8-8661-002590aecc79  ONLINE	   0	 0	 0
		logs
		  mirror-1									  ONLINE	   0	 0	 0
			gptid/d59dc571-7d7e-11e8-b9c5-0cc47a9cd5a4  ONLINE	   0	 0	 0
			gptid/d64df9e0-7d7e-11e8-b9c5-0cc47a9cd5a4  ONLINE	   0	 0	 0
		cache
		  gptid/dac3ea3e-7d7e-11e8-b9c5-0cc47a9cd5a4	ONLINE	   0	 0	 0
		  gptid/db865f7e-7d7e-11e8-b9c5-0cc47a9cd5a4	ONLINE	   0	 0	 0

errors: No known data errors

 

[Chris Moore]

Thanks for your help, guys!

You probably want to review this thread:

https://forums.freenas.org/index.php?threads/slog-benchmarking-and-finding-the-best-slog.63521/