Saving large array fails with savez_compressed() but works with save()

I got this strange problem on a CentOS box, Python 2.6.6, Numpy 1.9.1:

[minhle@node069 ~]$ python
Python 2.6.6 (r266:84292, Jan 22 2014, 09:42:36)
[GCC 4.4.7 20120313 (Red Hat 4.4.7-4)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import numpy as np
>>> np.version.version
'1.9.1'
>>> a = np.ones((775890380,))
>>> np.savez_compressed('/home/minhle/scratch/test.npz', a)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/minhle/.local/lib/python2.6/site-packages/numpy/lib/npyio.py", line 560, in savez_compressed
    _savez(file, args, kwds, True)
  File "/home/minhle/.local/lib/python2.6/site-packages/numpy/lib/npyio.py", line 597, in _savez
    format.write_array(fid, np.asanyarray(val))
  File "/home/minhle/.local/lib/python2.6/site-packages/numpy/lib/format.py", line 562, in write_array
    array.tofile(fp)
IOError: 775890380 requested and 233691638 written
>>> np.save('/home/minhle/scratch/test.npy', a)
>>> b = np.load('/home/minhle/scratch/test.npy')
>>> b[:10]
array([ 1.,  1.,  1.,  1.,  1.,  1.,  1.,  1.,  1.,  1.])
>>> quit()
[minhle@node069 ~]$ cat /etc/*-release
CentOS release 6.5 (Final)
Cluster Manager v5.2
slave
LSB_VERSION=base-4.0-amd64:base-4.0-noarch:core-4.0-amd64:core-4.0-noarch:graphics-4.0-amd64:graphics-4.0-noarch:printing-4.0-amd64:printing-4.0-noarch
CentOS release 6.5 (Final)
CentOS release 6.5 (Final)

[samuela]

I just got this error too but with np.savez as opposed to np.savez_compressed.

[pv]

savez needs to store files temporarily on disk, and perhaps you run out of space on /tmp. Try setting TMPDIR=$HOME/tmp or so.