iSCSI and Sync Writes

[NightNetworks]

I have recently configured a FreeNAS server and wanted to mess around with iSCSI for ESXi.

So I have searched around the forum and have seen that there has been a lot of conversations around iSCSI and Sync Writes... I know that this is something that I want to turn on however I wanted to clarify a couple of things first.

- I am a little confused where the Sync Writes needs to be enabled, FreeNAS or ESXi or Both? It was suggested in one post that I read (and I think I may have misread it) that by default Sync Writes are turned on for ESXi when using iSCSI. However from what I have read in other posts its not turned on in FreeNAS thus it does not matter what ESXi has configured...
- If this is something that needs to be configured on the FreeNAS side of things, where do I go to turn it on?

Sorry, for what is probably a stupid question.

Thanks in advance!

 

[viniciusferrao]

You should force sync writes on the dataset or pool where you'll export the iSCSI share. You can force sync writes with the "zfs set sync" command on the CLI.

 

[HoneyBadger]

Specifically the command is

Code:

zfs set sync=always datasetname

Write performance will be poor without an SLOG device.