diff options
Diffstat (limited to 'docs/Samba3-HOWTO/TOSHARG-locking.xml')
| -rw-r--r-- | docs/Samba3-HOWTO/TOSHARG-locking.xml | 89 |
1 files changed, 38 insertions, 51 deletions
diff --git a/docs/Samba3-HOWTO/TOSHARG-locking.xml b/docs/Samba3-HOWTO/TOSHARG-locking.xml index e76f456ffa..4a433fb6c3 100644 --- a/docs/Samba3-HOWTO/TOSHARG-locking.xml +++ b/docs/Samba3-HOWTO/TOSHARG-locking.xml @@ -69,7 +69,7 @@ server as well as on each MS Windows client! <indexterm><primary>deny modes</primary></indexterm> There are two types of locking that need to be performed by an SMB server. The first is <emphasis>record locking</emphasis> that allows a client to lock -a range of bytes in a open file. The second is the <emphasis>deny modes</emphasis> +a range of bytes in an open file. The second is the <emphasis>deny modes</emphasis> that are specified when a file is open. </para> @@ -92,7 +92,7 @@ many more differences, too many to be listed here. <para> <indexterm><primary>record locking</primary></indexterm> <indexterm><primary>byte-range lock</primary></indexterm> -Samba 2.2 and above implement record locking completely independent of the +Samba 2.2 and above implement record locking completely independently of the underlying UNIX system. If a byte-range lock that the client requests happens to fall into the range of 0 to 2^31, Samba hands this request down to the UNIX system. No other locks can be seen by UNIX, anyway. @@ -103,8 +103,8 @@ No other locks can be seen by UNIX, anyway. <indexterm><primary>rpc.lockd</primary></indexterm> Strictly speaking, an SMB server should check for locks before every read and write call on a file. Unfortunately, with the way fcntl() works, this can be slow and may overstress -the <command>rpc.lockd</command>. This is almost always unnecessary because clients are supposed to -independently make locking calls before reads and writes if locking is +the <command>rpc.lockd</command>. This is almost always unnecessary because clients are +independently supposed to make locking calls before reads and writes if locking is important to them. By default, Samba only makes locking calls when explicitly asked to by a client, but if you set <smbconfoption name="strict locking">yes</smbconfoption>, it will make lock checking calls on <emphasis>every</emphasis> read and write call. @@ -450,13 +450,10 @@ regularly opening the same file. <indexterm><primary>Multiuser databases</primary></indexterm> <indexterm><primary>management bottleneck</primary></indexterm> <indexterm><primary>oplocks disabled</primary></indexterm> -Multiuser databases clearly pose a risk due to their very nature &smbmdash; -they are typically heavily accessed by numerous users at random -intervals. Placing a multiuser database on a share with oplocks -enabled will likely result in a locking management bottleneck -on the Samba server. Whether the database application is developed -in-house or a commercially available product, ensure that the share -has oplocks disabled. +Multiuser databases clearly pose a risk due to their very nature &smbmdash; they are typically heavily +accessed by numerous users at random intervals. Placing a multiuser database on a share with oplocks enabled +will likely result in a locking management bottleneck on the Samba server. Whether the database application is +developed in-house or a commercially available product, ensure that the share has oplocks disabled. </para> </sect3> @@ -470,18 +467,13 @@ has oplocks disabled. <indexterm><primary>client-side data caching</primary></indexterm> <indexterm><primary>oplocks management</primary></indexterm> <indexterm><primary>disabling oplocks</primary></indexterm> -Process data management (PDM) applications such as IMAN, Enovia, and -Clearcase are increasing in usage with Windows client platforms and -therefore with SMB datastores. PDM applications manage multiuser -environments for critical data security and access. The typical PDM -environment is usually associated with sophisticated client design -applications that will load data locally as demanded. In addition, the -PDM application will usually monitor the data state of each client. -In this case, client-side data caching is best left to the local -application and PDM server to negotiate and maintain. It is -appropriate to eliminate the client OS from any caching tasks, and the -server from any oplocks management, by disabling oplocks on -the share. +Process data management (PDM) applications such as IMAN, Enovia, and Clearcase are increasing in usage with +Windows client platforms and therefore with SMB datastores. PDM applications manage multiuser environments for +critical data security and access. The typical PDM environment is usually associated with sophisticated client +design applications that will load data locally as demanded. In addition, the PDM application will usually +monitor the data state of each client. In this case, client-side data caching is best left to the local +application and PDM server to negotiate and maintain. It is appropriate to eliminate the client OS from any +caching tasks, and the server from any oplocks management, by disabling oplocks on the share. </para> </sect3> @@ -491,16 +483,12 @@ the share. <para> <indexterm><primary>oplock break</primary></indexterm> -Samba includes an &smb.conf; parameter called -<smbconfoption name="force user"/> that changes -the user accessing a share from the incoming user to whatever user is -defined by the smb.conf variable. If oplocks is enabled -on a share, the change in user access causes an oplock break to be sent -to the client, even if the user has not explicitly loaded a file. In -cases where the network is slow or unreliable, an oplock break can -become lost without the user even accessing a file. This can cause -apparent performance degradation as the client continually reconnects -to overcome the lost oplock break. +Samba includes an &smb.conf; parameter called <smbconfoption name="force user"/> that changes the user +accessing a share from the incoming user to whatever user is defined by the &smb.conf; variable. If oplocks is +enabled on a share, the change in user access causes an oplock break to be sent to the client, even if the +user has not explicitly loaded a file. In cases where the network is slow or unreliable, an oplock break can +become lost without the user even accessing a file. This can cause apparent performance degradation as the +client continually reconnects to overcome the lost oplock break. </para> <para> @@ -542,7 +530,7 @@ likely cause problems. The parameters are <para> <indexterm><primary>turn oplocks off</primary></indexterm> For most users, administrators, and environments, if these parameters -are required, then the better option is to simply turn oplocks off. +are required, then the better option is simply to turn oplocks off. The Samba SWAT help text for both parameters reads: <quote>Do not change this parameter unless you have read and understood the Samba oplock code.</quote> This is good advice. @@ -1096,6 +1084,7 @@ tdb(/usr/local/samba_2.2.7/var/locks/locking.tdb): rec_read bad magic <sect2> <title>Problems Saving Files in MS Office on Windows XP</title> +<indexterm><primary>KB 812937</primary></indexterm> <para>This is a bug in Windows XP. More information can be found in <ulink url="http://support.microsoft.com/?id=812937">Microsoft Knowledge Base article 812937</ulink></para>. @@ -1107,6 +1096,7 @@ tdb(/usr/local/samba_2.2.7/var/locks/locking.tdb): rec_read bad magic <para><quote>It sometimes takes approximately 35 seconds to delete files over the network after XP SP1 has been applied.</quote></para> +<indexterm><primary>KB 811492</primary></indexterm> <para>This is a bug in Windows XP. More information can be found in <ulink url="http://support.microsoft.com/?id=811492"> Microsoft Knowledge Base article 811492</ulink></para>. </sect2> @@ -1117,9 +1107,9 @@ tdb(/usr/local/samba_2.2.7/var/locks/locking.tdb): rec_read bad magic <title>Additional Reading</title> <para> -You may want to check for an updated version of this white paper on our Web site from -time to time. Many of our white papers are updated as information changes. For those papers, -the last edited date is always at the top of the paper. +You may want to check for an updated documentation regarding file and record locking issues on the Microsoft +<ulink url="http://support.microsoft.com/">Support</ulink> web site. Additionally, a search for the work +<literal>locking</literal> on the Samba <ulink url="http://www.samba.org/">web</ulink> site. </para> <para> @@ -1127,26 +1117,23 @@ Section of the Microsoft MSDN Library on opportunistic locking: </para> <para> -Opportunistic Locks, Microsoft Developer Network (MSDN), Windows Development > -Windows Base Services > Files and I/O > SDK Documentation > File Storage > File Systems -> About File Systems > Opportunistic Locks, Microsoft Corporation -<ulink noescape="1" url="http://msdn.microsoft.com/library/en-us/fileio/storage_5yk3.asp">http://msdn.microsoft.com/library/en-us/fileio/storage_5yk3.asp</ulink>. +<indexterm><primary>KB 224992</primary></indexterm> +Microsoft Knowledge Base, <quote>Maintaining Transactional Integrity with OPLOCKS</quote>, +Microsoft Corporation, April 1999, <ulink noescape="1" url="http://support.microsoft.com/?id=224992">Microsoft +KB Article 224992</ulink>. </para> <para> - Microsoft Knowledge Base Article Q224992, <?latex \linebreak ?><quote>Maintaining Transactional Integrity -with OPLOCKS</quote>, -Microsoft Corporation, April 1999, <ulink noescape="1" url="http://support.microsoft.com/default.aspx?scid=kb;en-us;Q224992">http://support.microsoft.com/default.aspx?scid=kb;en-us;Q224992</ulink>. +<indexterm><primary>KB 296264</primary></indexterm> +Microsoft Knowledge Base, <quote>Configuring Opportunistic Locking in Windows 2000</quote>, +Microsoft Corporation, April 2001 <ulink noescape="1" url="http://support.microsoft.com/?id=296264">Microsoft KB Article 296264</ulink>. </para> <para> -Microsoft Knowledge Base Article Q296264, <quote>Configuring Opportunistic Locking in Windows 2000</quote>, -Microsoft Corporation, April 2001 <ulink noescape="1" url="http://support.microsoft.com/default.aspx?scid=kb;en-us;Q296264">http://support.microsoft.com/default.aspx?scid=kb;en-us;Q296264</ulink>. -</para> - -<para> -Microsoft Knowledge Base Article Q129202, <quote>PC Ext: Explanation of Opportunistic Locking on Windows NT</quote>, -Microsoft Corporation, April 1995 <ulink noescape="1" url="http://support.microsoft.com/default.aspx?scid=kb;en-us;Q129202">http://support.microsoft.com/default.aspx?scid=kb;en-us;Q129202</ulink>. +<indexterm><primary>KB 129202</primary></indexterm> +Microsoft Knowledge Base, <quote>PC Ext: Explanation of Opportunistic Locking on Windows NT</quote>, +Microsoft Corporation, April 1995 <ulink noescape="1" url="http://support.microsoft.com/?id=129202">Microsoft +KB Article 129202</ulink>. </para> </sect1> |