Is it possible for your SLOG to be too large?
We are having trouble with our array going into serious write latency. When we execute a large data move, the array (3 striped mirrors of 6 8tb disk with a 1TB NMVe SLOG) the array will go into full write mode, with 2 large spikes every 5 minutes.
Is it possible that the SLOG is so large that it is filling up and then trying to flush to disk? When this happens, the entire TrueNAS box becomes unresponsive, including the web interface and even SSH. We just have to wait for it to stop before we can regain control. This causes our iSCSI-connected VMs to freeze since they can't access thier disks.
We have stopped doing major data moves and the problem has gone away for now, but we are leary of doing any large data moves because it may cause the problem to recur.
I know there has been discussion on proper sizing of an SLOG, but I find bits and pieces when I search. Can someone link me to a definitive guide that shows the entire calculation (write speed/network speed/etc) for calculating the proper size?
We are having trouble with our array going into serious write latency. When we execute a large data move, the array (3 striped mirrors of 6 8tb disk with a 1TB NMVe SLOG) the array will go into full write mode, with 2 large spikes every 5 minutes.
Is it possible that the SLOG is so large that it is filling up and then trying to flush to disk? When this happens, the entire TrueNAS box becomes unresponsive, including the web interface and even SSH. We just have to wait for it to stop before we can regain control. This causes our iSCSI-connected VMs to freeze since they can't access thier disks.
We have stopped doing major data moves and the problem has gone away for now, but we are leary of doing any large data moves because it may cause the problem to recur.
I know there has been discussion on proper sizing of an SLOG, but I find bits and pieces when I search. Can someone link me to a definitive guide that shows the entire calculation (write speed/network speed/etc) for calculating the proper size?