Hi Ed and Oleksandr, Thanks for the prompt replies!
There's no swapping or paging out (si=0 consistently in the vmstat output). Plenty of free memory during the reading process. I'm using 24 VM's (running under OpenStack) in 4 data centers. Each VM has two 2 VCPU's, 4GB of memory, and 50GB of disk space (40GB for Tahoe storage). All VM's were dedicated to the Tahoe experiments. I set up a separate Tahoe client to do the performance measurements through the Thaoe command line tools so that I could collect elapsed time easily. For example, $ tahoe create-alias grid $ time tahoe cp 383MB.mov grid: $ time tahoe cp grid:383MB.mov t.mov $ cmp 383MB.mov t.mov I'll run the same tests through the Web interface and check out the performance pages - thanks! Robin On Mon, Mar 4, 2013 at 11:09 AM, Oleksandr Drach <[email protected]>wrote: > *Robin,* > I think your grid speed is quite good. > Could you please briefly provide your hardware details? > > You can additionally check every download operation on Status > Page<http://yournode.com:3456/status/>. > Click on Status column and you'll find more > details<http://yournode.com:3456/status/down-0> > . > Timeline <http://yournode.com:3456/status/down-0/timeline> is also may be > very useful. > > You can find further readings on Tahoe-Lafs performance > here<https://tahoe-lafs.org/trac/tahoe-lafs/wiki/Performance>and > there <https://tahoe-lafs.org/trac/tahoe-lafs/wiki/Performance/Old>. > > *Zooko,* > I think adding "real" performance numbers to the Performance > page<https://tahoe-lafs.org/trac/tahoe-lafs/wiki/Performance> will > be really helpful for a lot of people. > > > *Sincerely, > Oleksandr Drach,* > > *e-mail: **[email protected]* <[email protected]>*.* > > > 2013/3/4 Ed Kapitein <[email protected]> > >> Hi Robin, >> >> I am quiet new too, and i ran into a "out of memory" situation, while >> reading a large file. >> Did you check to see if the reading machine starts swapping? >> ( you can check with top ) >> That could make the machine and the reading real slow. >> >> Kind regards, >> Ed >> >> On Mon, 2013-03-04 at 10:45 -0500, Robin Chen wrote: >> > Hi, >> > >> > >> > I have recently started my experiments with Tahoe and deployed 24 >> > Tahoe storage nodes in 4 data centers (using 9 out-of 24 coding), but >> > I'm running into a performance problem. >> > >> > >> > I'm new to this email list, so I'm not sure if this problem has been >> > discussed before or not. >> > >> > >> > I would expect the "reading" performance (reading 9 shares) to be >> > better than the "writing" performance (writing 24 shares in 4 >> > geographically-distribute data centers), but the reading time is >> > typically two times longer in most of my tests with files > 300MB. >> > >> > >> > For example, for a file size of 383MB, I'm getting about 16Mbps in >> > throughput for writing, but only about 8.8Mbps in reading. >> > >> > >> > Any possible explanation? >> > >> > >> > Thanks! >> > >> > >> > Robin >> > _______________________________________________ >> > tahoe-dev mailing list >> > [email protected] >> > https://tahoe-lafs.org/cgi-bin/mailman/listinfo/tahoe-dev >> >> >> _______________________________________________ >> tahoe-dev mailing list >> [email protected] >> https://tahoe-lafs.org/cgi-bin/mailman/listinfo/tahoe-dev >> > > > _______________________________________________ > tahoe-dev mailing list > [email protected] > https://tahoe-lafs.org/cgi-bin/mailman/listinfo/tahoe-dev > >
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