This bug affects me too. With 16 GB RAM ltsp-update-image needs 40 minutes and with 8 GB it needs only 3 minutes.
Results with 16GB RAM: real 40m58.672s user 14m15.420s sys 0m20.212s
Results with 8GB RAM: 3:12.53 elapsed 667.48 user 12.29 system
This bug affects me too.
With 16 GB RAM ltsp-update-image needs 40 minutes and with 8 GB it needs only 3 minutes.
Results with 16GB RAM:
real 40m58.672s
user 14m15.420s
sys 0m20.212s
Results with 8GB RAM:
3:12.53 elapsed
667.48 user
12.29 system