Blocked reads

[Georg Köster]

Hi,

 

if you are the wrong contact – I’m sorry. Don’t know where to drop this
information.

 

For many years it happens to me that a Samba installation can be fast on
writes but incredible slow on reads. Now it happened again with debian etch
stable and the default samba package (3.0.24). Client is a fresh XP SP2 or
SP3 and any smb.conf – it really doesn’t matter. 

 

What I want to tell you: As I accidentally opened a scp connection while
trying to read from samba, the blocking was instantly gone. It’s easy to
reproduce.

 

-          I copy a 7 GB file from a samba-share to the local disk via
Windows explorer. The result is an endless wait, since the data move just
bit by bit.

-          Now I switch to winscp and copy any other file from the samba
server to my local disk.

-          From that moment on and for the time winscp is copying, the
Windows copy boosts to normal 35 MB/s and the file is copied within 3
minutes.

-          If the winscp copy ends before the Windows copy is done, than
this transfer rate instantly drops to nearly zero again.

-          The problem is not restricted to large files, just easier to
analyse.

 

We are doing some rpc programming in other areas and remember similar
problems some years ago but don’t remember how it was solved. Do you
transfer in small pieces and close the ports after each one?

 

Georg Köster, Berlin

 

georg.koester at igk.de