Statistics on number of oplocks taken out on a Samba server
sharpe at ns.aus.com
Thu Jan 3 21:57:02 GMT 2002
Jim Morris wrote:
> Richard Sharpe wrote:
>> Does anyone have any statistics on the max and average number of
>> oplocks taken out by Windows clients against a Samba server?
>> Is it like 1/20 per client, 2/20, 0.5/10? Any gut feels at all?
> On several small to medium sized LAN's (up to 50 active Windows
> clients), I have often taken a "snapshot" of the lock status of Samba
> using smbstatus. I normally see no more than 10 to 20 active oplocks
> shown by smbstatus at any single point in time, even on the 50 user
Hmmm, that is useful info. My question was in the context of a kernel
implementation (under FreeBSD) of OpLocks. The code base I am working
with keeps oplocks in a singly linked list (SLIST_*...). This list will
have to be searched for every file open to look for oplocks. If a server
is supporting 1,000 clients, or even 10,000 clients :-), that could be a
lot of oplocks, and thus a long list to search :-(
More anecdotes required.
> My observations are that the use of oplocks is VERY application
> dependent. Some proprietary database applications I have worked on
> code for can open as many as 100 dBASE files on a Samba share.
> Depending on Samba and client settings, that could be as many as 100
> outstanding oplocks. Get several users running that application
> (written in Borland C++ Builder), and you can see a LOT of oplock and
> oplock break related log messages in the Samba log files, depending on
> the log level. Contrast that to a user running Word editing a
> document, who will only have a lock on the document(s) being edited.
> A user just connected to a share or browsing it with Windows Explorer
> will not have any outstanding oplocks.
> That said - in all LAN environments I work with, only data files are
> stored on the Samba server - applications are typically installed
> locally on the client systems. So you typically will only see one
> oplock per open file. If the apps were running from a network drive,
> I am sure oplock use would be significantly higher.
> I don't know if my highly NON-empirical data is any help, but there it
> is! ;-)
> Jim Morris (Jim at Morris.net)
Richard Sharpe, rsharpe at ns.aus.com, LPIC-1
www.samba.org, www.ethereal.com, SAMS Teach Yourself Samba
in 24 Hours, Special Edition, Using Samba
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