Subject: disk caching (was: Re: Really bad performance when doing newfs)
To: None <email@example.com>
From: Dieter <firstname.lastname@example.org>
Date: 02/04/2006 10:49:53
Thank you for pointing out
And yet, FreeBSD defaults to turning on the write cache in disks.
> This caching makes block-devices almost unusable
I find them quite usable.
> depriving the application of the ability to know the exact disk contents
> at any one instant in time
Most applications don't need to know. All the world is not a database.
> This makes predictable and reliable crash recovery of on-disk data structures
> (filesystems, databases etc.) impossible.
I was under the impression that filesystems had the ability to force
the order of writes when they needed to? Am I misremembering?
Is this a problem in NetBSD?
Databases can use raw partitions.
> For this reason, no serious applications rely on block devices
Only for wierd definitions of "serious".