[Samba] Samba + BDE and slow speed on reading (long)
Giovani Moda - MR Informática
giovani at mrinformatica.com.br
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
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
? 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 ?
? 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
Thanks for your inputs,
> Damien Dye BSC(hon)
> IT and Telecommunications Engineer
> Mckenna Group
> Lawn Road Industrial Estate
> Lawn Road
> United Kingdom
> S81 9LB
> Email : damiend at mckennagroup.co.uk
> Tel : (44) 01909541414
> Direct : (44) 01909541462
> Fax : (44) 01909541415
> Web : www.mckennagroup.co.uk
> Company Registered in England, McKenna Precision Castings Ltd
> Company Registration Number 1713320
> Registered address Lawn Road, Carlton-in-Lindrick, Worksop, Notts, S81 9LB
> -------- Original Message --------
> Subject: [Samba] Samba + BDE and slow speed on reading (long) (06-Feb-2008
> 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
>> 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
>> 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,
>> problem must be caused by that slow speed on receiving files from the
>> 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
>> 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
>> 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
>> fastest protocol and cannot be compared to samba, but still, that's a
>> 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
>> 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
>> the database from XP, the speed is OK too. The server is a brand new Core
>> 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
>> Both times, the server was connected to a D-Link DES-1024 switch.
>> NIC's and cables had no effect, but SO_RCVBUF=1 solved it instantly.
>> it be related tho this version of samba and the problem I'm having now?
>> Any thoughts?
>> Giovani Moda
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