[ZODB-Dev] Use of fsync in FileStorage

[Shane Hathaway]

On Thursday 29 July 2004 13:51 pm, Christian Robottom Reis wrote:
> Doesn't really seem to make *that* much of a difference; this may have
> to do with VFS fsync behaviour when using raid-1, or perhaps the write
> behaviour on these specific hard drives -- I am surprised so many others
> saw so much fluctuation in times.

I would expect fsync to make a big difference.  fsync waits for the disk to 
write everything currently pending to disk.  Disks without a battery backup 
have to seek in order to sync reliably, and since seek time is a few 
milliseconds, it's easy to see why a box would be limited to 100-200 fsyncs 
per second, regardless of the processor speed.

I don't like the way Zope behaves with respect to the disk.  It churns the 
disk before responding to the browser; no other program I use is so paranoid.  
Why bother?  When I actually care about the data Zope is storing, I use a 
UPS.  Does fsync provide any benefit that a UPS doesn't?

Shane