I asked > A followup to my question last week about wiping a disk: > > for those of you using > dd if=/dev/random of=/dev/rdsk/cXtXdXsX > how long does it usually take? On a 2gig disk after it had been running > for over 24 hours I phoned Sun Support to see if maybe I had gotten the > flags to dd wrong or something like that. The woman I spoke to was > insistent that a repartition and newfs was all that was necessary to > wipe a disk of all previous data. Yeah, right. Sure. And Microsoft > will start making a secure and well written product. So, how long does > that command usually take? > > TIA, and I will summarize. Damn, that was fast. /dev/random has to generate entropy and is very CPU intensive every time it is called. Use /dev/urandom if you must (it is orders of magnitude faster than /dev/random), but /dev/zero (which is orders of magnitude faster than /dev/urandom) with multiple passes (7 for government specs, I understand) is much faster and works fine. Also, tweak the block size. bs=1024k seems to be the fastest. dd if=/dev/zero of=/dev/rdsk/cXtXdXsX bs=1024k format (to label the disk again) rinse, lather, and repeat 7 times. Thanks to the 15 or so people that responded to my query within minutes... +-----------------------------------------------------------------------+ | Christopher L. Barnard O When I was a boy I was told that | | cbarnard@tsg.cbot.com / \ anybody could become president. | | (312) 347-4901 O---O Now I'm beginning to believe it. | | http://www.cs.uchicago.edu/~cbarnard --Clarence Darrow | +----------PGP public key available via finger or PGP keyserver---------+ _______________________________________________ sunmanagers mailing list sunmanagers@sunmanagers.org http://www.sunmanagers.org/mailman/listinfo/sunmanagersReceived on Wed May 19 12:46:24 2004
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