c0t0d0s0.org

Okay, quite often the configuration of a feature or application mandates that the data on the disk doesn´t change while you activate it. Okay, an easy way would be simply unmounting the disk. Okay, that´s possible but then you can´t access the data on the disk at all. You can´t even read from the filesystem, albeit this doesn´t change anything on the disk (okay, as long you´ve mounted the disk with noatime).

It´s one of the long lasting myths, that RAID needs hardware to be fast. It´s like "Disable autoneg" and "1 MHz per MBit". Those rules were true in the past but obsoleted by the time. But the RAID myth seems to be more persistant than all other before. Whenever i talk about ZFS RAID, the people stare at me and and i see the though "Oh, no, the guy talks about slow SW RAID". Okay, when you don´t believe me perhaps you believe a user our products: Robert Milkowski gives some numbers on RAID performance here and here.

Detlef Drewanz, a colleague from me, found an interesting way to migrate his filesystems from UFS to ZFS: The good old combination of ufsdump and ufsrestore. You have to be careful with ACL (seems to be fixes in Build 41) in your source filesystem but besides this this is an good way to do the migration.