> I don't think retransmissions of b0rken packets is a problem anymore, > most people > use ssh which provides good error detection at a fine grain. It is > rare that one would > need to resend an entire ZFS dump stream when using ssh (or TLS or ...) > > Archival tape systems are already designed to wrap the payload with > ECC. For > example, the T10000b is rated at 30 year shelf life and 10^-19 BER -- 4 > orders of > magnitude better than enterprise class HDDs and 5 orders of magnitude > better > than consumer class HDDs. > > Also, many enterprise backup solutions have long-term tape management > as part of > their core feature set. > > A well designed, enterprise class backup system should be easily > capable of > storing ZFS dump images reliably, safely, and securely.
Actually, this is a really good point. We have some FEC experts at work, and I asked them this question. They couldn't name any software package that does this, because it's always done in hardware. After conversation, I was shocked to learn how ridiculously everywhere FEC is in every device you use. It's required in your hard drive, your flash drive, your ram, your motherboard, your Ethernet. Everywhere. And it's absolutely a design decision how strong you want to build it. So for a commodity hard drive, you can expect lower grade, while an enterprise tape drive and tape media, you can rest assured have much stronger. Whenever a data stream gets corrupted, you can pretty well count on the idea that another layer of FEC wasn't going to save you; if you get any errors at all in your data, you're safe assuming the data is *dramatically* altered. There was some good info about it, I read in this article coincidentally yesterday. Read the section that says "Hard disks are unreliable" http://arstechnica.com/microsoft/news/2010/03/why-new-hard-disks-might-not-b e-much-fun-for-xp-users.ars _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
