Another reason to love ZFS

While perusing the ZFS mailing list last today, I came across several interesting replies to a message titled “recover zfs data from a crashed system?”. I have been using ZFS now for 6-months, and the following reply is just one of the reasons I trust my data with it:

“I built a test zpool spanning 7 drives (raidz) on S10U2. The 7 disks were split between 3 controllers. I then started replacing the 18GB drives with 36GB drives, one at a time, and watched it rebuild the zpool, growing as it did.Finally, when I had all the drives replaced, I took the system down, moved the drives around on the controllers, reloaded the OS onto the internal drives on my Sun Blade 1000 workstation. I then forced a write of random data to one of the drives in the 7 disk raidz array. Then I did the zpool import – it reported the array, with errors. I did the zpool import , and it came right in, and mounted up. From there I did a scrub (and yes, it did essentially chew up all available system resources, while it scrubbed the 200+GB pool on this small and not so mighty system), and it corrected all the issues. All in all it was a good test, and I was rather impressed that it was able to juggle re-ordering of the drives, re-enumeration of the controllers they were attached to, erasure of one of the drives, all while importing the pool on a rebuilt system.

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