Delayed reaction

Delayed reaction

Posted Dec 5, 2009 12:22 UTC (Sat) by paulj (subscriber, #341)
In reply to: Delayed reaction by dlang
Parent article: Journal-guided RAID resync

Note that the ZFS Intent Log doesn't affect the consistency of the filesystem. The fs is consistent without the intent log, thanks to the COW, Merkle tree arrangement. So its not solving any consistency problems, i.e.:

• ZFS is transactional, with or without the ZIL
• ZFS is always consistent on disk, with or without the ZIL

The ZIL is there to solve the problem of supporting performant synchronous writes. ZFS would still support consistent, synchronous writes without the ZIL, just they'd be very slow.

I think it'd be useful if you looked at this ZFS presentation, which is where I'm getting most of my info from. The OSOL ZFS community also has a source overview.

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