[Samba] Samba + BDE and slow speed on reading (long)
Giovani Moda - MR Informática
giovani at mrinformatica.com.br
Wed Feb 6 22:01:09 GMT 2008
> Several posters have said that the Realtek 8168 and 8169 chips have caused
> slow file transfers with Samba. They solved their problem by changing to
> another NIC.
Well, it's worth trying. I'll schedule the mainteinance with my client and
let you guys know. Any restrictions with D-Link DGE-530T?
Thanks,
Giovani
>
> Dale
>
> Giovani Moda - MR Informática wrote:
>> Hello list.
>>
>> I'm new here, and I'm joining because I'm having a problem wich I can't
>> figure out the solution myself. Here's what's happening:
>>
>> A Samba 3.0.24 is serving files to seven Windows XP clients. Three of
>> those clients run an application with a BDE database. The problem is that
>> when running this application on Samba, it gets very, VERY slow, causing
>> it to hang. I have noticed also an unusual low speed when receiving files
>> from the samba server over network. When sending files to the server, the
>> speed is OK. Since the databases used by that apllication have about 50Mb
>> each, the problem must be caused by that slow speed on receiving files
>> from the server.
>>
>> I've twiked the configuration a bit, and came to this results:
>>
>> socket options = SO_RCVBUF=65535 SO_SNDBUF=65535 TCP_NODELAY
>> IPTOS_LOWDELAY - Very slow on reading, fast when writing
>> socket options = TCP_NODELAY IPTOS_LOWDELAY - still slow on read, but a
>> little better. Fast when writing
>> socket options = TCP_NODELAY IPTOS_LOWDELAY SO_SNDBUF=32768 - significant
>> improvement when reading files, but the application still hangs due to
>> the slow speed. Fast when reading.
>> socket options = TCP_NODELAY IPTOS_LOWDELAY SO_SNDBUF=32768
>> SO_RCVBUF=32768 - same as above, but writing speed shows deterioration.
>>
>> Other significant parameters:
>>
>> max connections = 50
>> dos filetimes = yes
>> max open files = 4000
>> nt acl support = yes
>> preserve case = yes
>> strict locking = no
>> deadtime = 15
>> unix charset = iso8859-1
>> display charset = cp850
>> oplocks = no
>> kernel oplocks = no
>> level2 oplocks = no
>> local master = yes
>> os level = 64
>> domain master = yes
>> time server = yes
>> preferred master = yes
>> domain logons = yes
>> name resolve order = wins bcast host lmhosts
>> wins support = yes
>> wins proxy = yes
>> dns proxy = no
>>
>>
>> So, I went for socket options = TCP_NODELAY IPTOS_LOWDELAY
>> SO_SNDBUF=32768 and got these results:
>>
>> Copying a 45678592 bytes throug samba, it takes from 45 to 60 seconds to
>> transfer. The same file though FTP takes only 3.9 seconds. I know FTP is
>> the fastest protocol and cannot be compared to samba, but still, that's a
>> HUGE difference.
>>
>> As a desperate measure, I've copied the whole database to a XP machine,
>> shared the folder to the network, mapped it to the other stations, and
>> the application runs perfectly again.
>>
>> Conclusion: there's definitely a problem when reading files from samba
>> server. It's not network related, since FTP is really fast, and when
>> serving the database from XP, the speed is OK too. The server is a brand
>> new Core 2 Duo E4500, 2GB RAM, 160 GB HD SATAII, NIC Realtek r8169
>> connected to a DES-1008D Gigabit Switch. The distro in question is FC5
>> fully updated.
>>
>> As a related topic, I've came across a situation (two times and couting)
>> when writing files to the samba server is painfully slow. On both cases,
>> setting SO_RCVBUF=1 has resolved the problem. I don't know why, but it
>> did. Both times, the server was connected to a D-Link DES-1024 switch.
>> Switching NIC's and cables had no effect, but SO_RCVBUF=1 solved it
>> instantly. Could it be related tho this version of samba and the problem
>> I'm having now?
>>
>> Any thoughts?
>>
>> Thanks,
>>
>> Giovani Moda
>>
>
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