[Samba] smbmount read/write block size stuck at 4k

Dan Singletary dvsing at sonicspike.net
Wed Dec 8 02:59:38 GMT 2004

When using smbmount to mount a share from WinXP, I observed 
less-than-optimal throughput when copying a file from the remote share 
to a local disk.  Observation of the protocol dialog with Ethereal 
revealed that smbmount was making read requests for 4k bytes at a time. 
  Similar observation of protocol dialog between two WinXP boxes showed 
that the typical read request was for 64k.

I then tried to use smbclient to 'get' the file, and again observed 4k 
SMB read requests.  I found that using the '-b <buffersize>' option with 
smbclient is effective in REDUCING the buffer size as small as 1 byte 
(reflected in Ethereal showing 1 byte SMB read requests), however I am 
unable to use '-b' to increase the read requests beyond 4k.

Why does smbmount/smbclient only read  data at 4k per block?  This 
results in horribly poor performance (~4 MBytes/sec) on a gigabit 
network that should permit transfer rates that challenge the speed of 
the disk drives involved...


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