YES , The ashift=13 as same as the value in SD.confDid you note what was being reported for ashift when you re-created the pool with the Intel disk? If so, did this value change after the 4TB of writes when you could no longer remove the SLOG?
I see, I will try to use the rsync to restore data.The reason that I recommend the RSYNC is that it would rule out any issue having to do with a corrupted ZFS file system. Like any file system ZFS is not magic but does protect you from many things. The other benefit you will have is that it will eliminate any fragmentation present in your ZFS pool.
YES, I did modify sd.conf.Have you modified sd.conf in this setup to force a special ashift for the SSD?
I would avoid this.
But there is no powerloss the all time .....I would also avoid desktop class SSDs for an slog.
An Slog must offer powerloss protection, ultra low latency and high write iops or you should avoid an Slog as this may be even slower than using the onpool ZIL as a logdevice for sync write.