Samba Performance Tuning
Content Inside: Opportunistic locks, or oplocks, allow clients to cache files locally, improving per-
formance on the order of 30 percent. This option is now enabled by default. For
read-only files, the fake oplocks provides the same functionality without actu-
ally doing any caching. If you have files that cannot be cached, oplocks can be
turned off.
Database files should never be cached, nor should any files that are updated both
on the server and the client and whose changes must be immediately visible. For
these files, the veto oplock files option allows you to specify a list of individ-
ual files or a pattern containing wildcards to avoid caching. oplocks can be turned
off on a share-by-share basis if you have large groups of files you donâ t want
cached on clients. See Chapter 5, Browsing and Advanced Disk Shares, for more
information on opportunistic locks.
IP packet size (MTU)
Networks generally set a limit to the size of an individual transmission or packet
This is called the Maximum Segment Size, or if the packet header size is included,
the Maximum Transport Unit (MTU). This MTU is not set by Samba, but Samba
needs to use a max xmit (write size) bigger than the MTU, or throughput will be
reduced. This is discussed in further detail in the following note. The MTU is nor-
mally preset to 1500 bytes on an Ethernet and 4098 bytes on FDDI. In general,
having it too low cuts throughput, and having it too high causes a sudden perfor-
mance dropoff due to fragmentation and retransmissions.
Source: www.oreilly.com
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