Linked by Pobrecito Hablador on Mon 2nd Nov 2009 21:19 UTC
Sun Solaris, OpenSolaris One of the advantages of ZFS is that it doesn't need a fsck. Replication, self-healing and scrubbing are a much better alternative. After a few years of ZFS life, can we say it was the correct decision? The reports in the mailing list are a good indicator of what happens in the real world, and it appears that once again, reality beats theory. The author of the article analyzes the implications of not having a fsck tool and tries to explain why he thinks Sun will add one at some point.
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RE: .
by tobyv on Tue 3rd Nov 2009 00:56 UTC in reply to "."
tobyv
Member since:
2008-08-25

And what is this fsck supposed to check and fix? As soon as somebody can answer this a fsck tool wil be made i think.


Fixing/detecting corrupted SHA256 block hashes for the deduplication feature, for one. I've relied on file systems in the past that worked on a similar concept.

Nothing more terrifying than learning that a block of the root fs has a hash of zero!

The fs will need to be offline and the hash values are metadata, so it falls into the 'fsck' category IMHO.

Reply Parent Score: 2

RE[2]: .
by c0t0d0s0 on Tue 3rd Nov 2009 08:00 in reply to "RE: ."
c0t0d0s0 Member since:
2008-10-16

That opens an interesting question: What's the correct stuff. The checksum or the data ;) Furthermore: Dedup uses the already computed checksums of the filesystem. You don't have to sync it to your data.

Reply Parent Score: 1

RE[3]: .
by cerbie on Tue 3rd Nov 2009 09:13 in reply to "RE[2]: ."
cerbie Member since:
2006-01-02

The solution to that would be parity data saved inline with normal data, sacrificing a little bit of space. Then, some small % of data could be hosed, yet still recovered, whether it was the data, hash, or parity.

But, since server people want better drives and more backups, us cheapskates want all of that 1TB our $80 paid for, and we all want faster storage...I don't see it happening ;) .

Reply Parent Score: 2

RE[2]: .
by renhoek on Tue 3rd Nov 2009 22:27 in reply to "RE: ."
renhoek Member since:
2007-04-29

"zfs scrub" does this. And taking the filesystem offline for this is a waste of time.

Reply Parent Score: 2