[mythtv-users] NAS mobo

Yan Seiner yan at seiner.com
Thu Aug 21 21:41:45 UTC 2008


On Thu, August 21, 2008 2:36 pm, Bobby Gill wrote:
> On Thu, Aug 21, 2008 at 4:10 PM, Dan Ritter
> <dsr-myth at tao.merseine.nu>wrote:
>
>> On Thu, Aug 21, 2008 at 07:04:42AM -0700, Yan Seiner wrote:
>> >
>> > What I don't want to do is to implement a solution today and then have
>> > to rip it out a year later.  If nothing else, do you have any idea how
>> > long rsync takes to dump and verify a TB over an ethernet connection?
>> 2+
>> > days, and it's not quite done.....  I hate to think what I'd have to
>> do
>> > with a 5 or 10 TB array.....
>>
>> Gigabit ethernet, 80% efficiency, straight throughput: 800Mb/s,
>> = 100MB/s, = 10,000 seconds for a terabyte. So, 2 hours 45
>> minutes. Call it 3 hours per TB.
>>
>> You aren't getting 100MB/s off your disks, or you aren't able to
>> write that fast, or you're using rsync inappropriately (perhaps
>> in combination with SSH). I would guess all three. If you want
>> to transfer a large amount of data quickly, rsync's default
>> options aren't the way to go. Rsync might not be the way to go
>> for the initial transfer, really.
>>
>> -dsr-
>>
>> --
>> http://tao.merseine.nu/~dsr/eula.html<http://tao.merseine.nu/%7Edsr/eula.html>is
>> hereby incorporated by reference.
>>
>> When freedom gets lots of exercise, it protects itself.
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>>
>
>
> Sorry, haven't followed the entire thread so disregard if irrelevant but
> I'd
> agree with Dan. I transfer many TB regularly over my home network using
> mounted NFS and regular ol' cp -rup for large initial transfers and just
> have rsync -avzdp afterwards in cronjobs or as required.
>

Well, yabbut... ATM I'm dumping to an old server with 100 mb/s ethernet. 
I have thousands and thousands of small files.  And the files have
multiple hardlinks, which really, really slows rsync down.  (And why cp
won't work.)

Gah.  I wish it was 3 hours.  I wish I had a new NAS with gigabit
ethernet.  I wish I had a pony.  :-)

At least it's done.  Finally.

--Yan


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