Error 121: Unable to synchronously open file (unable to lock file) (Lab)

Arjun Chawla
  • 26 Feb

Hi, i have been loading the Group positions of halos , pretty much the same way for 2 years but i recently ran into a problem which i verified is not due to any updates on my laptop or the network i am on.

So when i use the line :
GroupPos = il.groupcat.loadHalos(basePath,99,fields=['GroupPos'])[3]*aa/hh

i get error : 'OSError: [Errno 121] Unable to synchronously open file (unable to lock file, errno = 121, error message = 'Remote I/O error')'

I also attach a full image of the error.

One of the weird things is i can brute force it. It occurs 9 times out of 10, but 1 time when i run the cell, it goes through and the error doesn't appear.
Since this line is part of functions i create, it gets frustrating as they can fill up the memory as well.

Help with this will be really appreciated.

Thanks
ArjunScreenshot 2026-02-26 at 12.58.13.png

Dylan Nelson
  • 26 Feb

This is some sort of problem with a recent change of the server.

(You are running in the Lab, correct?)

There was a recent change to try to fix this (on Feb 26 at roughly 10am EST). Can you try running similar things more now, and let me know if there is any improvement?

Arjun Chawla
  • 27 Feb

Hi Dylan,
Sorry for the late response, things got a bit busy for me last evening. I am running on the Lab and the problem still seems to persist, but thanks for the clarification on why it might be happening.
Arjun

Dylan Nelson
  • 27 Feb

Thanks, I have made one more change.

Can you keep trying now, and let me know if you see any difference?

Arjun Chawla
  • 27 Feb

Hi Dylan, its still the same issue. I tried logging out and logging in as well and close and reopen notebooks, but it didn't work.

Arjun Chawla
  • 27 Feb

Its actually gotten worse. As i mentioned earlier i would run the cell multiple times, and it would work sometimes, now it always gives the error

Dylan Nelson
  • 2 Mar

The issue seems to be related to this:

https://github.com/h5py/h5py/issues/1679

can you try the fix proposed at the bottom?

Arjun Chawla
  • 21h

Hi Dylan, due to me travelling at the moment, i will be able to check and get back to you on Wednesday. Thanks for getting back to me.

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