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Diffstat (limited to 'docs/textdocs/Speed.txt')
| -rw-r--r-- | docs/textdocs/Speed.txt | 83 |
1 files changed, 70 insertions, 13 deletions
diff --git a/docs/textdocs/Speed.txt b/docs/textdocs/Speed.txt index 5dfd70323b1..fee111b6ec2 100644 --- a/docs/textdocs/Speed.txt +++ b/docs/textdocs/Speed.txt @@ -1,8 +1,14 @@ -This file tries to outline the ways to improve the speed of a Samba server. +!== +!== Speed.txt for Samba release 2.0.0-alpha11 09 Oct 1998 +!== +Contributor: Andrew Tridgell +Date: January 1995 +Status: Current -Andrew Tridgell -January 1995 +Subject: Samba performance issues +============================================================================ +This file tries to outline the ways to improve the speed of a Samba server. COMPARISONS ----------- @@ -30,6 +36,47 @@ hardware Samba should certainly be competitive in speed with other systems. +OPLOCKS +------- + +Oplocks are the way that SMB clients get permission from a server to +locally cache file operations. If a server grants an oplock +(opportunistic lock) then the client is free to assume that it is the +only one accessing the file and it will agressively cache file +data. With some oplock types the client may even cache file open/close +operations. This can give enormous performance benefits. + +With the release of Samba 1.9.18 we now correctly support opportunistic +locks. This is turned on by default, and can be turned off on a share- +by-share basis by setting the parameter : + +oplocks = False + +We recommend that you leave oplocks on however, as current benchmark +tests with NetBench seem to give approximately a 30% improvement in +speed with them on. This is on average however, and the actual +improvement seen can be orders of magnitude greater, depending on +what the client redirector is doing. + +Previous to Samba 1.9.18 there was a 'fake oplocks' option. This +option has been left in the code for backwards compatibility reasons +but it's use is now deprecated. A short summary of what the old +code did follows. + +Old 'fake oplocks' option - deprecated. +--------------------------------------- + +Samba can also fake oplocks, by granting a oplock whenever a client +asks for one. This is controlled using the smb.conf option "fake +oplocks". If you set "fake oplocks = yes" then you are telling the +client that it may agressively cache the file data for all opens. + +Enabling 'fake oplocks' on all read-only shares or shares that you know +will only be accessed from one client at a time you will see a big +performance improvement on many operations. If you enable this option +on shares where multiple clients may be accessing the files read-write +at the same time you can get data corruption. + SOCKET OPTIONS -------------- @@ -80,7 +127,10 @@ MAX XMIT At startup the client and server negotiate a "maximum transmit" size, which limits the size of nearly all SMB commands. You can set the maximum size that Samba will negotiate using the "max xmit = " option -in smb.conf. +in smb.conf. Note that this is the maximum size of SMB request 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 +honours this limit. It defaults to 65536 bytes (the maximum), but it is possible that some clients may perform better with a smaller transmit unit. Trying values @@ -111,7 +161,20 @@ no". This will gain you a lot in opening and closing files but will mean that (in some cases) the system won't force a second user of a file to open the file read-only if the first has it open read-write. For many applications that do their own locking this -doesn't matter, but for some it may. +doesn't matter, but for some it may. Most Windows applications +depend heavily on "share modes" working correctly and it is +recommended that the Samba share mode support be left at the +default of "on". + +The share mode code in Samba has been re-written in the 1.9.17 +release following tests with the Ziff-Davis NetBench PC Benchmarking +tool. It is now believed that Samba 1.9.17 implements share modes +similarly to Windows NT. + +NOTE: In the most recent versions of Samba there is an option to use +shared memory via mmap() to implement the share modes. This makes +things much faster. See the Makefile for how to enable this. + LOG LEVEL --------- @@ -187,7 +250,7 @@ Samba supports reading files via memory mapping them. One some machines this can give a large boost to performance, on others it makes not difference at all, and on some it may reduce performance. -To enable you you have to recompile Samba with the -DUSE_MMAP=1 option +To enable you you have to recompile Samba with the -DUSE_MMAP option on the FLAGS line of the Makefile. Note that memory mapping is only used on files opened read only, and @@ -239,6 +302,7 @@ person even reported a speed drop of a factor of 30 when he went from It probably depends a lot on your hardware, and the type of unix box you have at the other end of the link. + MY RESULTS ---------- @@ -263,10 +327,3 @@ smbclient running on another linux box. Maybe I'll add those results here someday ... -COMMENTS --------- - -If you've read this far then please give me some feedback! Which of -the above suggestions worked for you? - -Mail the samba mailing list or samba-bugs@anu.edu.au |