[tahoe-dev] Tahoe-LAFS v1.8 planning / Administrivia / Big Picture

[Francois Deppierraz]

Hi Zooko,

Better late than never, I just found your email in the
already-read-but-not-yet-responded list ;)

On 08/04/2010 04:23 AM, Zooko O'Whielacronx wrote:

> What's the next step? I still don't know exactly what the UX would be
> for this feature. Would you have a flat file containing a list of
> serverids followed by categories like this:

This list should probably get synced from the introducer

> # serverid category:id, category:id, category:id, ...
> alt6cjddwfnwrnct4lx2ypwricrgtoam colo:us-west-1a, rack:5, chassis:3
> cufg4m4c7bfujnf5tkhjdazicn7ifkae colo:us-west-1b, rack:1, chassis:1
> e5itfysbe3qeqgzflxdnm6ypraufj6vj colo:singapore-1, rack:1, chassis:1
> fp3xjndgjt2npubdl2jqqb26clanyag7 colo:singapore-1, rack:1, chassis:2
> 
> and would the server selection algorithm automatically use the
> following as its highest-priority requirement: "spread the shares as
> evenly as possible among the different numbers of each category"? And
> if there were more than one category would it treat each successive
> one as the next-highest-priority after the previous priorities were
> satisfied?
> 
>> One of the current deployment I did is a grid of 3 servers, each with 24
>> SATA disks. One Tahoe-LAFS storage node per disk and each server is located
>> in a different datacenter.
> 
> Sweet! How is it working? Could you give us some problem reports,
> success reports, benchmarks? :-)

Enough of problem reports in my previous mail, now on to the quick
benchmark results. These operations were run directly on a Tahoe-LAFS
gateway running release 1.8.0 on one of the three big servers.

Uploading a single 100 MB file takes 277 seconds, that's about 2.9 Mbps.

Downloading the same file takes 351 seconds, about 2.3 Mbps.

> I've never seen real production use of K and M values that large.
> Everyone always uses the default M=10. K=3. I did actually set K=15
> and M=30-something for a while on a test grid that had 15 live
> servers. It worked okay. If you try setting something like M=72, K=22,
> H=70 then please do run measurements of performance and do please
> report your results to this list! :-)

This makes me wonder if Kyle Markley's benchmark script could easily be
run on an existing grid to benchmarks typical operations such download,
upload, check and repair on a single big file, multiple small files, and so?

François