sync delay and consitency
gemini at geminix.org
Thu Nov 27 14:18:42 PST 2003
Ion-Mihai Tetcu wrote:
> I have a machine that randomly crashes. I wonder if lowering
> Variable Default Description
> kern.filedelay 30 time to delay syncing files
> kern.dirdelay 29 time to delay syncing directories
> kern.metadelay 28 time to delay syncing metadata
> would help having a more up-to-date fs (using soft-updates).
You can reduce these settings in order to narrow the window which you
would lose data in if the system crashed. However, it is important that
you keep the numerical order of these variables.
> Also is there a reason for the 30-29-28 (the 1 differece between)
> sequence ?
It gives a FS w/soft-updates its crash resilience, by ensuring the order
of disk updates for these three data types. Meta data first, then
directory data, and finally the actual file contents.
Uwe Doering | EscapeBox - Managed On-Demand UNIX Servers
gemini at geminix.org | http://www.escapebox.net
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