[volunteergrid2-l] New Member

[Christoph Langguth]

Hi all,

this mail is a response to all of the replies I've received so far, so 
Shawn and Vlastimil, you're only quoted "indirectly", but your feedback 
is of course appreciated :-)

>
> [From my understanding, your uploads will proceed at the speed of the
> slowest node's upload speeds...unfortunately, for many of us in the
> states, residential (i.e. DSL) upload speeds are horrendous. This,
> combined with the fact that ea. upload is actually sent multiple times
> will combine to make for a *very* slow (weeks) initial upload. That
> said, I wish I had access to similar network connectivity!!]
>

I'm aware of that, and upload speed is not terribly much of an issue. 
What is more important is data availability. A full backup may well take 
a week or more, and even differential backups might take a substantial 
amount of time. It's not like every second matters, and it's only used 
as the second line of defense.

In the sense of: if someone screws up and needs to regain a file from 2 
days ago, this is covered by our local backup strategy. But if the 
entire office burns down, including the local server, then we can well 
live with the documents from the past 3 days being lost. We'll probably 
have other, real-life-problems, by then ;-)


>
> [Unless the requirement was changed, I believe 500GB is the min and 1TB
> the max. There is a good piece on the Wiki regarding this range and why
> it was chosen. You might consider carving out a 1TB partition from your
> new disk or simply plugging in an USB external HDD. Many of the original
> nodes (in the states) of which I'm aware use LVM and/or a RAID variant.
> I picked up a 2TB disk for less than $80 USD about 9 months ago ... am
> guessing you can find similar HDDs for even less now?]
>

Initially, I actually wanted to use a 500GB HDD left over from a 
previous setup, attached externally by USB. But it seems that for this 
particular combination, we got bitten by a serious bug either in Linux 
itself, or its USB implementation, or the firmware of the external HDD 
casing, or the HDD itself... I can't tell. ( 
http://ubuntuforums.org/showthread.php?t=1214003 ). In any case, that 
constellation would even lead up to complete system lock ups, so from 
personal experience using internal drives instead of USB is more 
sensible ;-)

Combining yours and Shawn's reply, I believe that getting a 1.5 or 2TB 
disk (still need to check exactly which drive to buy with some other 
people here) will do just fine. In the end it's a one-time investment of 
about 80 to 200 €...

One thing I'm wondering about though: Why would you use RAID for the 
provisioning of storage? From what I know, the entire point of using 
tahoe-lafs is distributed (replicated) storage, so local replication 
isn't necessary. In other words: The filesystem itself intrinsically 
supports the "loss" of your local part of storage, so why replicate it 
again?


Thanks & cheers,

Chris

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