Bad Performance in 18 TB extent.

[thedoginthewok]

Hello,

I have created a 18 TB file extent on my 18TB RaidZ, because performance over Samba wasn't good for my usecase.

Write speed is 20 Megabyte per second. Read speed is about 70 Megabyte per Second.
Same raidz with Samba is about 100 Megabyte per second read and write.

local write speed with dd is about 200 Megabyte per second and local read speed is 150 Megabyte per second.

I used a ZFS Kernel Tune plugin and changed the setting to "6GB Memory". Before that read speeds where higher than write speeds.

[raulfg3]

if you ask for help, you need to provide more info.

see rule 2: viewtopic.php?f=1&t=5

[thedoginthewok]

I already found the problem.

I set the "Logical Block Length" option of the iscsi target to 4096, now the performance is much much better. It maxes out the capabilities of the NIC now.