On Wed, 21 Apr 2004, Steve Watt wrote:
> On Apr 21, 13:28, Julian Elischer wrote: > } Subject: Re: how to flush out cache.? > } > } On Wed, 21 Apr 2004, Steve Watt wrote: > } > } > In article <[EMAIL PROTECTED]> you write: > } > > > } > >Ok so I have an application where I need to > } > >reread a file I have just written to ensure that it went to disk > } > >correctly.. > } > > } > What are you hoping to accomplish? There are probably other ways > } > to solve the larger problem. > } > } I thought I was being clear.. > } I need to remove all the pages from cache so that a reread of the file > } is forced to go to disk. > } and I don't want to go read a 2GB dummy file to force the flush.. > > No, my question is "what are you trying to accomplish with the > reread", at a higher level than "I want to know it's on disk". Is > there some reason you have for not trusting the hardware? Are you > trying to do a database commit protocol? Debugging the storage > system? > > } Someone suggested that I read the file usign 'dump' through the raw > } device.. > > Even doing that doesn't necessarily mean the bits have made it onto > the rotating media. There can also be caches in the disk controller, > and/or caches on the drive itself. If you're trying for a case where > you want to pull the power, unmounting and remounting the filesystem > will get it about as close as you can. The disk caches are small enough.. we are talking about multi gigabyte files getting a few blocks bad somewhere in the middle. (and yes the machines have enough RAM to cache the files). > > -- > Steve Watt KD6GGD PP-ASEL-IA ICBM: 121W 56' 57.8" / 37N 20' 14.9" > Internet: steve @ Watt.COM Whois: SW32 > Free time? There's no such thing. It just comes in varying prices... > _______________________________________________ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to "[EMAIL PROTECTED]"
