On February 13, 2009 12:41:12 PM -0500 Miles Nordin <car...@ivy.net> wrote:
"fc" == Frank Cusack <fcus...@fcusack.com> writes:
fc> if you have 100TB of data, wouldn't you have a completely
fc> redundant storage network
If you work for a ponderous leaf-eating brontosorous maybe. If your
company is modern I think having such an oddly large amount of data in
one pool means you'd more likely have 70 whitebox peecees using
motherboard ethernet/sata only, connected to a mesh of unmanaged L2
switches (of some peculiar brand that happens to work well.) There
will always be one or two peecees switched off, and constantly
something will be resilvering. The home user case is not really just
for home users. I think a lot of people are tired of paying quadruple
for stuff that still breaks, even serious people.
oh i dunno. i recently worked for a company that practically defines
modern and we had multiples of 100TB of data. Like you said, not all
in one place, but any given piece was fully redundant (well, if you
count RAID-5 as "fully" ... but I'm really referring to the infrastructure).
I can't imagine it any other way ... the cost of not having redundancy
in the face of a failure is so much higher compared to the cost of
building in that redundancy.
Also I'm not sure how you get 1 pool with more than 1 peecee as zfs is
not a cluster fs. So what you are talking about is multiple pools,
and in that case if you do lose one (not redundant for whatever reason)
you only have to restore a fraction of the 100TB from backup.
fc> Isn't this easily worked around by having UPS power in
fc> addition to whatever the data center supplies?
In NYC over the last five years the power has been more reliable going
into my UPS than coming out of it. The main reason for having a UPS
is wiring maintenance. And the most important part of the UPS is the
externally-mounted bypass switch because the UPS also needs
maintenance. UPS has never _solved_ anything, it always just helps.
so in the end we have to count on the software's graceful behavior,
not on absolutes.
I can't say I agree about the UPS, however I've already been pretty
forthright that UPS, etc. isn't the answer to the problem, just a
mitigating factor to the root problem.
-frank
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