The other thing going on here is that every write is going to be COW, which isn't ideal for VM images. Another thing that I wonder is what SSD this is and if it's supporting deterministic TRIM, since discard is enabled. And I'm not sure that md by default is passing down trim (?). This is on md raid? What level? If it's 56 then there's a separate enabler for raid56 discard. In general if this isn't an SSD that supports queued trim commands you're better off without discard mount option and just running fstrim manually once a week or even once a day is OK if it's a very busy SSD, just schedule it for a time when it's typically idle.
Chris Murphy -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
