Linked by Thom Holwerda on Tue 17th Sep 2013 22:04 UTC, submitted by garyd
General Development

ZFS is the world's most advanced filesystem, in active development for over a decade. Recent development has continued in the open, and OpenZFS is the new formal name for this open community of developers, users, and companies improving, using, and building on ZFS. Founded by members of the Linux, FreeBSD, Mac OS X, and illumos communities, including Matt Ahrens, one of the two original authors of ZFS, the OpenZFS community brings together over a hundred software developers from these platforms.

ZFS plays a major role in Solaris, of course, but beyond that, has it found other major homes? In fact, now that we're at it, how is Solaris doing anyway?

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RE: avoids the Raid 5 'write hole'
by akro on Wed 18th Sep 2013 09:55 UTC in reply to "avoids the Raid 5 'write hole'"
akro
Member since:
2005-07-06

RAID 10 is not sufficient for large sata drives. Urecoververable read errors are a fact of life and the ability to recover data from either a second set of parity information or from reconstruct is the a must to get by a URE...

RAID 6 provides this, raid 10 does not...

Tripple mirror is another option...

Reply Parent Score: 4

Alfman Member since:
2011-01-28

akro,

"Urecoververable read errors are a fact of life and the ability to recover data from either a second set of parity information or from reconstruct is the a must to get by a URE."

IMHO RAID offers good protection for complete disk failures, but it's ill suited for single occurrences of URE. If a single URE occurs, it doesn't necessarily represent a physical error with the hard drive (power loss, EM radiation, solar flare, etc). RAID cannot easily differentiate between a faulty drive and a good drive containing bad data, so it rejects a drive containing 100%-1 good data because of a single unrecoverable read error. This puts the rest of the array at higher risk since it's possible (if not likely) that another drive has another URE which is valid on the decommissioned drive.


"RAID 6 provides this, raid 10 does not...Tripple mirror is another option..."

We could theoretically bump it up to arbitrary levels of disk redundancy at the expense of efficiency. However I think it would make some sense to engineer a better solution that explicitly addresses the difference between URE and total drive loss.

My own solution would be to have network distributed redundancy rather than adding more redundancy through RAID. I've been working on something similar for a while for my own project.

Reply Parent Score: 4