On Fri, Mar 30, 2012 at 05:33:58PM -0400, Shawn Willden wrote: > > Can you please tell more about the VG2 grid? I clean missed it. > > (Sorry I'm slow to respond -- I'm vacationing with my family and often have > better things to do than read email :-) ). > > Volunteer Grid 2 is a Tahoe grid composed of volunteers all over the world. > Learning from some problems that the first volunteer grid had, I suggested > to early members that VG2 establish some clear and somewhat restrictive > policies in order to ensure that the grid was useful for system backups. > > Two specific backup-driven requirements we had were high > reliability/availability and relatively high capacity. To that end, we > established a 95% nominal up time requirement and a 500 GB minimum node > capacity requirement. We also avoid co-located nodes and disallow usage of > more than min(storage_provided, 1 TB). The limit on usage is to avoid > having one user deploy, say, 10 TB and then try to consume that much from > the grid, swamping the rest of the servers.
I would like to contribute ~TByte on a GBit/s link. I've passed on the email so there might be other takers as well. The process is described on http://www.bigpig.org/ ? > > > servers because the math of erasure coding works against you when the > > > individual nodes are unreliable, and we ban co-located servers and > prefer > > > to minimize the number of servers owned and administered by a single > person > > > in order to ensure greater independence. > > > > > > How has that worked out? Well, it's definitely constrained the growth > rate > > > of the grid. We're two years in and still haven't reached 20 nodes. > And > > > > It doesn't surprise me at all, since I've never heard a single squeak > > about it in the usual channels. (And I'm moderately well-informed > > in such matters). > > I'm surprised. It was definitely announced here when it was created, and > discussed occasionally since. If it was just limited to tahoe-dev it definitely did not see wide circulation. I realize you don't want ephemeral nodes; maybe there should be a probation period (demonstrated uptime, etc). > > > although our nodes have relatively high reliability, I'm not sure we've > > > actually reached the 95% uptime target -- my node, for example, was down > > > for over a month while I moved, and we recently had a couple of outages > > > caused by security breaches. > > > > > > However, we do now have 15 solid, high-capacity, relatively available > (90%, > > > at least) nodes that are widely dispersed geographically (one in Russia, > > > six in four countries in Europe, seven in six states in the US; not sure > > > about the other). So it's pretty good -- though we do need more nodes. > > > > How large is the total storage capacity? What about introducer nodes, is > > there just one? > > Total storage capacity, as reported by the stats gatherer, is around 14 TB. > That's disk used (~6 TB) plus disk available (~8 TB). As near as I can > tell by eyeballing the graph and summing my estimates is that consumption > grows by about 40 GB per day. We have a helper but it's lightly used. > Only one introducer. The node on the slowest network connection has about How are updates to new versions handled? > 1 Mbps of bandwidth, two or three nodes are on gigabit links, most are 6-50 > Mbps, IIRC. Hardware is similarly varied, with the low end being a small > NAS box, the high end being some fairly powerful servers in data centers, > and everything in between including some virtual servers. > > Upload performance, as measured from my machine (which has a 50 Mbps up, > 100 Mbps down connection), averages about about 300 KBps, before erasure > coding, so with my settings I get around 100 KBps net upload rate. I > haven't done any download tests recently, but in the past they've been > approximately the same as upload speeds, but without the erasure coding > penalty. > > -- > > Shawn > _______________________________________________ > tahoe-dev mailing list > [email protected] > http://tahoe-lafs.org/cgi-bin/mailman/listinfo/tahoe-dev -- Eugen* Leitl <a href="http://leitl.org";>leitl</a> http://leitl.org ______________________________________________________________ ICBM: 48.07100, 11.36820 http://www.ativel.com http://postbiota.org 8B29F6BE: 099D 78BA 2FD3 B014 B08A 7779 75B0 2443 8B29 F6BE _______________________________________________ tahoe-dev mailing list [email protected] http://tahoe-lafs.org/cgi-bin/mailman/listinfo/tahoe-dev
