git clone http:// fails some times with "Request for d53.. aborted"

[Yaroslav Halchenko <yoh@onerussian.com>]

even when (v 2.7.0) ran on the box where the server is, so
unlikely to be network issue

or from my laptop (v 2.9.3) with ok but wifi with a weakish signal to the
access point:

$> ( set -e; for s in {1..100}; do rm -rf fbirn_phaseIII ; git clone http://datasets.datalad.org/nidm/fbirn_phaseIII/.git; done; )
Cloning into 'fbirn_phaseIII'...
Checking connectivity... done.
Cloning into 'fbirn_phaseIII'...
error: Request for d53302dfc7ad13b786923927021039d21a10d5bd aborted
error: Unable to find d53302dfc7ad13b786923927021039d21a10d5bd under http://datasets.datalad.org/nidm/fbirn_phaseIII/.git
Cannot obtain needed tree d53302dfc7ad13b786923927021039d21a10d5bd
while processing commit 22dd4c49417cad6f4082ac2aebef45da8b6e473d.
error: fetch failed.

even if I build fresh 2.10.0, discovered that we can trace now CURL calls

$> export PATH=$HOME/proj/misc/git:$PATH
$> git version
git version 2.10.0
$> ( set -e; for s in {1..100}; do rm -rf fbirn_phaseIII ; GIT_TRACE_CURL=/tmp/git-trace-curl-failed.log git clone http://datasets.datalad.org/nidm/fbirn_phaseIII/.git &&  mv /tmp/git-trace-curl-failed.log /tmp/git-trace-curl-good.log || exit 1; done; ) 
Cloning into 'fbirn_phaseIII'...
warning: templates not found /home/yoh/share/git-core/templates
... a few more ...
Cloning into 'fbirn_phaseIII'...
warning: templates not found /home/yoh/share/git-core/templates
error: Request for d53302dfc7ad13b786923927021039d21a10d5bd aborted
error: Unable to find d53302dfc7ad13b786923927021039d21a10d5bd under http://datasets.datalad.org/nidm/fbirn_phaseIII/.git
Cannot obtain needed tree d53302dfc7ad13b786923927021039d21a10d5bd
while processing commit 22dd4c49417cad6f4082ac2aebef45da8b6e473d.
error: fetch failed.
( set -e; for s in {1..100}; do; rm -rf fbirn_phaseIII; GIT_TRACE_CURL= git  )  18.70s user 8.01s system 34% cpu 1:16.84 total

NB 
- note that it is d53302dfc7ad13b786923927021039d21a10d5bd all the time!
- that one corresponds to a tree
$> git show d53302dfc7ad13b786923927021039d21a10d5bd
tree d53302dfc7ad13b786923927021039d21a10d5bd

1ec/
da9/
- I do not see that object being reported as failed to be found on the server:

$> grep d5/3302dfc7ad13b786923927021039d21a10d5bd /var/log/apache2/datasets.datalad.org-error.log
$> grep d5/3302dfc7ad13b786923927021039d21a10d5bd /var/log/apache2/datasets.datalad.org-access.log
129.170.31.34 - - [09/Sep/2016:14:14:25 -0400] "GET /nidm/fbirn_phaseIII/.git/objects/d5/3302dfc7ad13b786923927021039d21a10d5bd HTTP/1.1" 200 72
...
- and the logs say that only "good" run had it requested:

$> zgrep 3302dfc7ad13b786923927021039d21a10d5bd git-trace-curl-*.log.gz     
git-trace-curl-good.log.gz:18:09:13.749268 http.c:517              => Send header: GET /nidm/fbirn_phaseIII/.git/objects/d5/3302dfc7ad13b786923927021039d21a10d5bd HTTP/1.1


and here are those two GIT_TRACE_CURL traces from good and bad runs -- may be
someone with a better clue could figure it out or any other information I
should provide to help pin point why that "request for d5... aborted" ;)

http://www.onerussian.com/tmp/git-trace-curl-good.log.gz
http://www.onerussian.com/tmp/git-trace-curl-failed.log.gz

Thanks in advance and please CC me in replies
-- 
Yaroslav O. Halchenko
Center for Open Neuroscience     http://centerforopenneuroscience.org
Dartmouth College, 419 Moore Hall, Hinman Box 6207, Hanover, NH 03755
Phone: +1 (603) 646-9834                       Fax: +1 (603) 646-1419
WWW:   http://www.linkedin.com/in/yarik