Date: Wed, 15 Mar 2006 14:48:31 +0100 (CET) From: Oliver Fromme <olli@lurza.secnetix.de> To: freebsd-stable@FreeBSD.ORG, Vadim Goncharov <vadim_nuclight@mail.ru> Subject: Re: swap at beginning of slice - danger? Message-ID: <200603151348.k2FDmVht027797@lurza.secnetix.de> In-Reply-To: <1591151085.20060315181926@mail.ru>
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Vadim Goncharov <vadim_nuclight@mail.ru> wrote: > I have 5.5-PRERELEASE server in production, booting from ad0s1: > > # BLOCKSIZE=512 swapinfo > Device 512-blocks Used Avail Capacity > /dev/ad0s1b 2097152 52872 2044280 3% > /dev/ad1s1b 2097152 51952 2045200 2% > Total 4194304 104824 4089480 2% > # bsdlabel ad0s1 | fgrep b: > b: 2097152 0 swap > > Previously, on a 4.11 system, swapinfo said that swap size was less than > size of b: partition on a slice - it was ok, as boot sectors are > located at beginning of slice. But now, sizes match exactly. What > changed and is it dangerous nowadays to have swap partition at offset 0 ? The code in sys/swap_pager.c does not touch the first two blocks, where blocks are measured in PAGE_SIZE units. The smallest page size supported on FreeBSD architectures is 4 KB (on i386), so that's at least 2 * 4k, which is 16 sectors on the disk. That's enough to skip MBR, disklabel and boot blocks. In other words: You're save. No danger. No need to worry. Best regards Oliver -- Oliver Fromme, secnetix GmbH & Co. KG, Marktplatz 29, 85567 Grafing Dienstleistungen mit Schwerpunkt FreeBSD: http://www.secnetix.de/bsd Any opinions expressed in this message may be personal to the author and may not necessarily reflect the opinions of secnetix in any way. > Can the denizens of this group enlighten me about what the > advantages of Python are, versus Perl ? "python" is more likely to pass unharmed through your spelling checker than "perl". -- An unknown poster and Fredrik Lundh
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