>>>>> "fc" == Frank Cusack <fcus...@fcusack.com> writes: >>>>> "dd" == David Dyer-Bennet <d...@dd-b.net> writes:
fc> If you go to a future version of zfs, simply replace all your
fc> "full" filesystem streams with new ones,
I still think you should not be storing these streams at all, for
reasons you describe later.
fc> The real problem here is lack of checksums and inability to
fc> restore the good parts of a stream if there is just one bad
fc> part.
there ARE checksums in 'zfs send' streams. That's the mechanism
through which single bit flips manage to invalidate the entire stream.
from my quick testing, 'tar' does not have checksums, and some
versions of the 'cpio' stream DO have checksums.
dd> put firewire cards into my two Linux servers for access to my
dd> external hard drives, and also used it on my Windows desktop
dd> and laptop boxes. That's at least three different external
dd> enclosure models and three different controllers.
dd> None of them seemed to be noticeably faster than USB.
In general I don't notice too much how fast things are. I just walk
away and come back when they're done. so, I believe you.
dd> So I've stopped buying firewire.
fine, that's reasonable. The cost premium is excessive.
but, not only speed. it is also less crappy than USB. especially
around here where problems get blamed on dropped SYNC CACHE commands
or buggy FTL's or whatever, maybe you care about general
crappyness-level. OTOH if you manage to get a working enclosure,
which even if you pay for firewire you can still never even prove, the
problems will just get blamed on the disk drive or Solaris's USB
driver or some war story about a low-quality two-foot USB cable, so
maybe it makes sense to get the crappiest cheapest case possible.
I think there is only one kind of host controller on Firewire, like
how on USB there are only two kinds of host controller. there were
some weird ones before, but now it is all OHCI. Though several
companies make chips that conform to OHCI, I've not heard of any
relevant differences among them. There are many firewire-to-PATA/SATA
bridges, and they DO have relevant differences in both speed and
correctness. You need to get the Oxford brand because they're the
ones who have delivered fast and non-buggy firmware since the
beginning.
The BSD firewire stack took like a decade to become useable after its
first release, while the BSD USB stack was working well pretty soon
after its release. so I wonder if Linux and Solaris have similar
problems. If they do, it could nullify Firewire's supposed advantage
(except on Mac OS where the stack is fine), or maybe you just need to
try again with newer Linux/Solaris kernel.
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