[Samba] Samba + BDE and slow speed on reading (long)

Thu Feb 7 11:16:05 GMT 2008

> 1) are your hdd tuned up look in your syslog for disk problems.

nope, HD is working fine. No reading errors, and hdparm shows

/dev/sda:
 Timing buffered disk reads:  204 MB in  3.01 seconds =  67.71 MB/sec

> 2) socket options apparently shouldn't be used with Linux 2.6 kernels

Tried without them, it just made it worse. The only improvement I got 
happened when using the socked options I've mentioned on my last post.

> 3) switching off oplocks stops client side caching have you got oplocks on 
> on the xp host also ??

I've disabled oplocks trying to get a better performance. Acctualy, I just 
forgot to set it back on, but it really made no difference in speed. Are you 
talking about enabling oplocks on Windows XP with the registry key 
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\LanmanServer\Parameters\EnableOplocks 
? Haven't tried. I'll have a look into it.

> 4) TCP window size on your XP host are they set to the highest possible ?

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\TcpWindowSize 
? What is the highest value I can set here?

> 5) Realtek NIc are know to be poor in speed and reliability consider a 
> better one.

First step to take. If it shows improvement, I'll take the rest of your 
suggestions.

Thanks for your inputs,

Giovani
>
>
>
> --------------------------------------------------------------------------
> Damien Dye BSC(hon)
> IT and Telecommunications Engineer
> Mckenna Group
> Lawn Road Industrial Estate
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> Worksop
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> Email  : damiend at mckennagroup.co.uk
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> -------- Original Message --------
> Subject: [Samba] Samba + BDE and slow speed on reading (long) (06-Feb-2008 
> 15:32)
> From:    giovani at mrinformatica.com.br
> To:      damiend at mckennagroup.co.uk
>
>> 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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