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| author | Gerald Carter <jerry@samba.org> | 2003-10-10 16:46:22 +0000 |
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| committer | Gerald Carter <jerry@samba.org> | 2003-10-10 16:46:22 +0000 |
| commit | fec4b31bc1a76e408732e1a80b366d97fcf38143 (patch) | |
| tree | e23398c2bcc4e3b2da28c8007ca453228aefb44f /docs/htmldocs/speed.html | |
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diff --git a/docs/htmldocs/speed.html b/docs/htmldocs/speed.html deleted file mode 100644 index b55989d053..0000000000 --- a/docs/htmldocs/speed.html +++ /dev/null @@ -1,141 +0,0 @@ -<html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>Chapter 39. Samba Performance Tuning</title><link rel="stylesheet" href="samba.css" type="text/css"><meta name="generator" content="DocBook XSL Stylesheets V1.60.1"><link rel="home" href="index.html" title="SAMBA Project Documentation"><link rel="up" href="Appendixes.html" title="Part VI. Appendixes"><link rel="previous" href="Other-Clients.html" title="Chapter 38. Samba and Other CIFS Clients"><link rel="next" href="DNSDHCP.html" title="Chapter 40. DNS and DHCP Configuration Guide"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Chapter 39. Samba Performance Tuning</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="Other-Clients.html">Prev</a> </td><th width="60%" align="center">Part VI. Appendixes</th><td width="20%" align="right"> <a accesskey="n" href="DNSDHCP.html">Next</a></td></tr></table><hr></div><div class="chapter" lang="en"><div class="titlepage"><div><div><h2 class="title"><a name="speed"></a>Chapter 39. Samba Performance Tuning</h2></div><div><div class="author"><h3 class="author"><span class="firstname">Paul</span> <span class="surname">Cochrane</span></h3><div class="affiliation"><span class="orgname">Dundee Limb Fitting Centre<br></span><div class="address"><p><tt class="email"><<a href="mailto:paulc@dth.scot.nhs.uk">paulc@dth.scot.nhs.uk</a>></tt></p></div></div></div></div><div><div class="author"><h3 class="author"><span class="firstname">Jelmer</span> <span class="othername">R.</span> <span class="surname">Vernooij</span></h3><div class="affiliation"><span class="orgname">The Samba Team<br></span><div class="address"><p><tt class="email"><<a href="mailto:jelmer@samba.org">jelmer@samba.org</a>></tt></p></div></div></div></div><div><div class="author"><h3 class="author"><span class="firstname">John</span> <span class="othername">H.</span> <span class="surname">Terpstra</span></h3><div class="affiliation"><span class="orgname">Samba Team<br></span><div class="address"><p><tt class="email"><<a href="mailto:jht@samba.org">jht@samba.org</a>></tt></p></div></div></div></div></div><div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><a href="speed.html#id2976235">Comparisons</a></dt><dt><a href="speed.html#id2976281">Socket Options</a></dt><dt><a href="speed.html#id2976372">Read Size</a></dt><dt><a href="speed.html#id2976422">Max Xmit</a></dt><dt><a href="speed.html#id2976477">Log Level</a></dt><dt><a href="speed.html#id2976507">Read Raw</a></dt><dt><a href="speed.html#id2976592">Write Raw</a></dt><dt><a href="speed.html#id2976655">Slow Logins</a></dt><dt><a href="speed.html#id2976683">Client Tuning</a></dt><dt><a href="speed.html#id2976707">Samba Performance Problem Due to Changing Linux Kernel</a></dt><dt><a href="speed.html#id2976766">Corrupt tdb Files</a></dt></dl></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2976235"></a>Comparisons</h2></div></div><div></div></div><p> -The Samba server uses TCP to talk to the client. Thus if you are -trying to see if it performs well, you should really compare it to -programs that use the same protocol. The most readily available -programs for file transfer that use TCP are ftp or another TCP-based -SMB server. -</p><p> -If you want to test against something like an NT or Windows for Workgroups server, then -you will have to disable all but TCP on either the client or -server. Otherwise, you may well be using a totally different protocol -(such as NetBEUI) and comparisons may not be valid. -</p><p> -Generally, you should find that Samba performs similarly to ftp at raw -transfer speed. It should perform quite a bit faster than NFS, -although this depends on your system. -</p><p> -Several people have done comparisons between Samba and Novell, NFS or -Windows NT. In some cases Samba performed the best, in others the worst. I -suspect the biggest factor is not Samba versus some other system, but the -hardware and drivers used on the various systems. Given similar -hardware, Samba should certainly be competitive in speed with other -systems. -</p></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2976281"></a>Socket Options</h2></div></div><div></div></div><p> -There are a number of socket options that can greatly affect the -performance of a TCP-based server like Samba. -</p><p> -The socket options that Samba uses are settable both on the command -line with the <tt class="option">-O</tt> option, or in the <tt class="filename">smb.conf</tt> file. -</p><p> -The <a class="indexterm" name="id2976313"></a><i class="parameter"><tt>socket options</tt></i> section of the <tt class="filename">smb.conf</tt> manual page describes how -to set these and gives recommendations. -</p><p> -Getting the socket options correct can make a big difference to your -performance, but getting them wrong can degrade it by just as -much. The correct settings are very dependent on your local network. -</p><p> -The socket option TCP_NODELAY is the one that seems to make the biggest single difference -for most networks. Many people report that adding -<a class="indexterm" name="id2976350"></a><i class="parameter"><tt>socket options</tt></i> = TCP_NODELAY -doubles the read performance of a Samba drive. The best explanation I have seen for -this is that the Microsoft TCP/IP stack is slow in sending TCP ACKs. -</p></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2976372"></a>Read Size</h2></div></div><div></div></div><p> -The option <a class="indexterm" name="id2976382"></a><i class="parameter"><tt>read size</tt></i> affects the overlap of disk -reads/writes with network reads/writes. If the amount of data being -transferred in several of the SMB commands (currently SMBwrite, SMBwriteX and -SMBreadbraw) is larger than this value, then the server begins writing -the data before it has received the whole packet from the network, or -in the case of SMBreadbraw, it begins writing to the network before -all the data has been read from disk. -</p><p> -This overlapping works best when the speeds of disk and network access -are similar, having little effect when the speed of one is much -greater than the other. -</p><p> -The default value is 16384, but little experimentation has been -done as yet to determine the optimal value, and it is likely that the best -value will vary greatly between systems anyway. A value over 65536 is -pointless and will cause you to allocate memory unnecessarily. -</p></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2976422"></a>Max Xmit</h2></div></div><div></div></div><p> - At startup the client and server negotiate a <i class="parameter"><tt>maximum transmit</tt></i> size, -which limits the size of nearly all SMB commands. You can set the -maximum size that Samba will negotiate using the <a class="indexterm" name="id2976442"></a><i class="parameter"><tt>max xmit</tt></i> option -in <tt class="filename">smb.conf</tt>. Note that this is the maximum size of SMB requests that -Samba will accept, but not the maximum size that the client will accept. -The client maximum receive size is sent to Samba by the client and Samba -honors this limit. -</p><p> -It defaults to 65536 bytes (the maximum), but it is possible that some -clients may perform better with a smaller transmit unit. Trying values -of less than 2048 is likely to cause severe problems. -In most cases the default is the best option. -</p></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2976477"></a>Log Level</h2></div></div><div></div></div><p> -If you set the log level (also known as <a class="indexterm" name="id2976487"></a><i class="parameter"><tt>debug level</tt></i>) higher than 2 -then you may suffer a large drop in performance. This is because the -server flushes the log file after each operation, which can be quite -expensive. -</p></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2976507"></a>Read Raw</h2></div></div><div></div></div><p> -The <a class="indexterm" name="id2976517"></a><i class="parameter"><tt>read raw</tt></i> operation is designed to be an optimized, low-latency -file read operation. A server may choose to not support it, -however, and Samba makes support for <a class="indexterm" name="id2976534"></a><i class="parameter"><tt>read raw</tt></i> optional, with it -being enabled by default. -</p><p> -In some cases clients do not handle <a class="indexterm" name="id2976552"></a><i class="parameter"><tt>read raw</tt></i> very well and actually -get lower performance using it than they get using the conventional -read operations. -</p><p> -So you might like to try <a class="indexterm" name="id2976573"></a><i class="parameter"><tt>read raw</tt></i> = no and see what happens on your -network. It might lower, raise or not effect your performance. Only -testing can really tell. -</p></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2976592"></a>Write Raw</h2></div></div><div></div></div><p> -The <a class="indexterm" name="id2976602"></a><i class="parameter"><tt>write raw</tt></i> operation is designed to be an optimized, low-latency -file write operation. A server may choose to not support it, however, and Samba makes support for -<a class="indexterm" name="id2976618"></a><i class="parameter"><tt>write raw</tt></i> optional, with it being enabled by default. -</p><p> -Some machines may find <a class="indexterm" name="id2976637"></a><i class="parameter"><tt>write raw</tt></i> slower than normal write, in which -case you may wish to change this option. -</p></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2976655"></a>Slow Logins</h2></div></div><div></div></div><p> -Slow logins are almost always due to the password checking time. Using -the lowest practical <a class="indexterm" name="id2976666"></a><i class="parameter"><tt>password level</tt></i> will improve things. -</p></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2976683"></a>Client Tuning</h2></div></div><div></div></div><p> -Often a speed problem can be traced to the client. The client (for -example Windows for Workgroups) can often be tuned for better TCP -performance. Check the sections on the various clients in -<link linkend="Other-Clients">. -</p></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2976707"></a>Samba Performance Problem Due to Changing Linux Kernel</h2></div></div><div></div></div><p> -A user wrote the following to the mailing list: -</p><p> -I am running Gentoo on my server and Samba 2.2.8a. Recently -I changed kernel version from <tt class="filename">linux-2.4.19-gentoo-r10</tt> to -<tt class="filename">linux-2.4.20-wolk4.0s</tt>. And now I have a performance issue with Samba. -Many of you will probably say, “<span class="quote">Move to vanilla sources!</span>” -Well, I tried that and it didn't work. I have a 100mb LAN and two computers (Linux and -Windows 2000). The Linux server shares directories with DivX files, the client -(Windows 2000) plays them via LAN. Before when I was running the 2.4.19 kernel -everything was fine, but now movies freeze and stop. I tried moving -files between the server and Windows and it is terribly slow. -</p><p> -The answer he was given is: -</p><p> -Grab the mii-tool and check the duplex settings on the NIC. -My guess is that it is a link layer issue, not an application -layer problem. Also run ifconfig and verify that the framing -error, collisions, and so on, look normal for ethernet. -</p></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2976766"></a>Corrupt tdb Files</h2></div></div><div></div></div><p> -Our Samba PDC server has been hosting three TB of data to our 500+ users -[Windows NT/XP] for the last three years using Samba without a problem. -Today all shares went very slow. Also the main smbd kept -spawning new processes so we had 1600+ running smbd's (normally we avg. 250). -It crashed the SUN E3500 cluster twice. After a lot of searching, I -decided to <b class="command">rm /var/locks/*.tdb</b>. Happy again. -</p><p> -<span class="emphasis"><em>Question:</em></span> Is there any method of keeping the *.tdb files in top condition or -how can I detect early corruption? -</p><p> -<span class="emphasis"><em>Answer:</em></span> Yes, run <b class="command">tdbbackup</b> each time after stopping nmbd and before starting nmbd. -</p><p> -<span class="emphasis"><em>Question:</em></span> What I also would like to mention is that the service latency seems -a lot lower than before the locks cleanup. Any ideas on keeping it top notch? -</p><p> -<span class="emphasis"><em>Answer:</em></span> Yes. Same answer as for previous question! -</p></div></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="Other-Clients.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="Appendixes.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="DNSDHCP.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Chapter 38. Samba and Other CIFS Clients </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> Chapter 40. DNS and DHCP Configuration Guide</td></tr></table></div></body></html> |