Date: Sun, 25 May 2003 12:43:16 -0400 From: Chuck Swiger <cswiger@mac.com> To: D Velez <dvelez502@verizon.net> Cc: questions@freebsd.org Subject: Re: using dd to copy my freebsd partion to another drive Message-ID: <3ED0F2A4.8050107@mac.com> In-Reply-To: <3ED0E9B0.4060703@verizon.net> References: <3ED0E9B0.4060703@verizon.net>
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D Velez wrote: [ ...] > but all have different block sizes and I am confuse. I see some as > bs=512 bs=1024 bs=8192, etc.... > > Is there a way to calculate the block size of the > two hard drives myself or is there a standard > block size to use for any hard drive, cdrom and floppy. Many devices actually have physical 512-byte sectors (not CD's and DVD's though), so 512 is the closest thing to a "standard" block size. People commonly use larger block sizes because multi-sector reads go faster in most circumstances. Try comparing bs=512 and bs=5120 and see for yourself. Also, note that dd is best used when the source and destination are identical: if your other drive is a different size, you might find using dump and restore to be a better bet. -Chuck
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