Date: Sun, 06 Oct 2002 07:44:27 -0700 From: "Jacob S. Barrett" <jbarrett@amduat.net> To: barbish@a1poweruser.com Cc: freebsd-questions@FreeBSD.ORG Subject: Re: Block Zeroing Tool Message-ID: <3DA04C4B.8090806@amduat.net> References: <MIEPLLIBMLEEABPDBIEGGEDJCMAA.barbish@a1poweruser.com>
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Yes I have tested it, and it works great. Be sure to turn compression on to high to get the best results. Here is what I saw after zeroing the unallocated blocks using the dd command below. FreeBSD partition size: 11G Allocated space: 6G Ghost image size: 3.4G Before zeroing out the images on this box were between 8-9G. Needless to say our IT guy is much happier that my box isn't chewing up 9G per image on the system anymore. And I am happy that imaging this machine only takes an hour now rather than 4. -Jake JoeB wrote: > > -----Original Message----- > From: owner-freebsd-questions@FreeBSD.ORG > [mailto:owner-freebsd-questions@FreeBSD.ORG]On Behalf Of Dan Nelson > Sent: Friday, October 04, 2002 10:33 AM > To: Jacob S. Barrett > Cc: freebsd-questions@FreeBSD.ORG > Subject: Re: Block Zeroing Tool > > In the last episode (Oct 04), Jacob S. Barrett said: > >>Is there a tool for FreeBSD that zeros the unallocated blocks on a >>filesystem? >> >>The company I work for has an image on demand system for our lab >>machines. This system relies on ghost which only supports file by >>file imaging on certain file systems. I want to take disk images of >>certain FreeBSD installations. Ghost will only take sector by sector >>images of FreeBSD partitions. Since it is doing this it stores all >>the "junk" unused blocks as well. This makes for a very large image >>even with high compression. If I can zero out the unused blocks >>before taking the image with high compression the image size should >>be much smaller. >> >>So, is there utility to zero out those blocks? Does this make sense? >>Is there a better way to take images of FreeBSD machines? > > > dd if=/dev/zero of=filler bs=1m ; rm filler > > > > I also have tried to use ghost to make image backups of FBSD, > but the image is the same size as the FBSD slice. > Have you tested the solution posted above to zero out the unused > disk space in the FBSD slice so ghost will only image bkup real data? > Did it work like you hoped? > -- Jacob S. Barrett jbarrett@amduat.net www.amduat.net "I don't suffer from insanity, I enjoy every minute of it." To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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