Linked by Thom Holwerda on Mon 18th Jan 2010 16:57 UTC, submitted by wanker90210
Hardware, Embedded Systems ACM's latest journal had an interesting article about RAID which suggested it might be time for triple parity raid. "How much longer will current RAID techniques persevere? The RAID levels were codified in the late 1980s; double-parity RAID, known as RAID-6, is the current standard for high-availability, space-efficient storage. The incredible growth of hard-drive capacities, however, could impose serious limitations on the reliability even of RAID-6 systems. Recent trends in hard drives show that triple-parity RAID must soon become pervasive."
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RE[6]: RAID Z
by computeruser on Tue 19th Jan 2010 18:35 UTC in reply to "RE[5]: RAID Z"
computeruser
Member since:
2009-07-21

We have >30 years of experience with dealing with FS and volume manager errors. In essence, even if your FS completely screwed up huge chunks of its tables (no matter how many copies of said tables the FS stores), in most cases the data is still salvageable.

Have you ever heard of a backup?
We have >20 years of experience in getting screwed by RAID errors. If something goes wrong at the array level and you somehow lose the array data/parity mapping or parts of it, the data is doomed. Period.

Here is a link to the Wikipedia page on backups, in case you are not familiar:
http://en.wikipedia.org/wiki/Backup
3. As such, I'm less afraid of trying new FS's, ext3, ext4, btrfs, ZFS. As long as I can access the on-disk data when everything goes to hell, I'm willing to take the chance. (Of-cause, as long as I don't get silent corruption that goes undetected for years...)

Why take a chance when you can make backups?

ZFS is relatively new and it combines 3 layers that I personally prefer them to be separate. A simple bug in one of the bottom layers (say, the pool management layer) can spell an end to your data in an recoverable way. And with a file-system as complex and relatively immature as ZFS (compared to say, ext2/3 or NTFS), this a -major- flaw

So your complaint is nothing to do with the actual design itself, but just that it's new.

OS lock-in

FreeBSD also has ZFS and there is a Mac OS X port. OpenSolaris is open-source; the result of lock-in if it was the only OS with ZFS is minimal.
In any case, with virtualization it doesn't matter.
And also: md and ext4 are Linux only.
patent issues (that prevent other OS from implementing ZFS)

What patents in ZFS that prevent reimplementation? Why do you keep repeating this? Are you sure you are not trolling?

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