O_Direct Error - Write through / Write back


Well-Known Member
Dec 26, 2018

I've gotten the O_DIRECT error when starting VMs. I have (1) SSD at 232gb and (1) 1tb disk drive. I configured as RAID 0 just to get things going as I will be changing my configuration in the future.

I read in the documentation to enable write back to stop the O_DIRECT error. This solves the problem, but when write through is enabled it also stops the error

What is the difference between write through and write back?

Hello there,

It's techniques to improve write speed on slow spin disks, which deals with write pages, different techniques changes performance You can click in Help at the bottom left.

i guess you use a directory storage on top of zfs? if yes, please don't, use zfs directly via a 'zfs storage'


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