Date: Mon, 27 Oct 2003 21:26:20 -0500 (EST) From: Robert Watson <rwatson@FreeBSD.org> To: Stefan Walter <sw@gegenunendlich.de> Cc: current@FreeBSD.org Subject: Re: GBDE performance on ZIP disks Message-ID: <Pine.NEB.3.96L.1031027212114.99244E-100000@fledge.watson.org> In-Reply-To: <20031027125318.GB1582@kyuzo.dunkelkammer.void>
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On Mon, 27 Oct 2003, Stefan Walter wrote: > is there a way to speed up writing to a gbde encrypted ZIP disk? > Copying 37 MB of data to an encrypted disk (in a SCSI drive) that has > been initialized with "newfs -O 2 -U /dev/da1a.bde" takes ~180 seconds, > which is ~200KB/s. Copying the same amount of data to the disk without > using gbde takes ~50 seconds, which is ~740KB/s. > > I guess this problem is similar to the one you have when using msdosfs > on a SCSI ZIP drive, which is also very slow. > > Using a different sector size than the default 512, which is also the > sector size of the media, doesn't seem to be possible and always results > in a "gbde: write sector 0: Operation not permitted". Playing around > with newfs's options didn't help so far, either. How do things look performance-wise if you do a raw sector read comparison with dd at various blocksizes? My recollection is that our msdos code would benefit hugely from the addition of clustering support, but UFS2 with a fragment size matching GBDE's notion shouldn't present the same problem... Robert N M Watson FreeBSD Core Team, TrustedBSD Projects robert@fledge.watson.org Network Associates Laboratories
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