Austin wrote:
> I've been trying to figure out how the copies command works and have been
> experimenting, but I haven't really seen any results (both with 5 physical
> drives I will soon add to my data pool as a 2nd RAIDZ and on a virtual
> machine with two RAIDZ in a pool). First: Is data copied across physical
> devices or virtual devices in a pool (thus could it work with a single RAIDZ,
> or would I need multiple virtual devices in the pool)? I've been trying to
> add some redundancy to my personal files in a RAID-Z array so that if two
> drives go down my important data will still be safe, but experimentation has
> led to me seeing no redundancy for filesystems set with copies=3 before
> copying dat to them. I have tried downing two out of 5 drives in a single
> RAIDZ pool and downing 2/3 drives in one RAIDZ in a dual-RAIDZ pool.
>
I made some pretty pictures describing copies at:
http://blogs.sun.com/relling/entry/zfs_copies_and_data_protection
The most common failure mode is unrecoverable read, not complete
disk failure. Copies is a good technique to help protect you from
unrecoverable reads.
-- richard
_______________________________________________
zfs-discuss mailing list
zfs-discuss@opensolaris.org
http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
