Date: Sun, 3 Jan 2010 08:00:57 +1100 From: Peter Jeremy <peterjeremy@acm.org> To: Pieter de Goeje <pieter@degoeje.nl> Cc: Poul-Henning Kamp <phk@phk.freebsd.dk>, freebsd-current@freebsd.org, freebsd-arch@freebsd.org Subject: Re: File system blocks alignment Message-ID: <20100102210056.GD32012@server.vk2pj.dyndns.org> In-Reply-To: <201001012153.44349.pieter@degoeje.nl> References: <61364.1262345170@critter.freebsd.dk> <201001012153.44349.pieter@degoeje.nl>
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--x4pBfXISqBoDm8sr Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Thanks for that testing - the results are quite enlightening. Given that the PC architecture forces unaligned partition boundaries by default, these drives are likely to wind up with a bad reputation for performance. On 2010-Jan-01 21:53:43 +0100, Pieter de Goeje <pieter@degoeje.nl> wrote: >- Partition size was 10GB, dump archive ~550MB (dump of /). The archive ea= sily >fitted in main memory (8GB). =2E.. >It was somewhat surprising to see restore being faster than tar in the ali= gned >case though. Mounting async or using soft updates resulted in a 6sec resto= re,=20 >while tar took about 8sec. With async or softupdates, there is likely to be virtually no physical write activity during the restore, with all the data winding up in the buffer cache to be flushed during the unmount. IMO, the 'restore' timing should include the unmount, changing: > cd /mnt > echo "restore" >> $results > time -ao $results restore -rf $fsarchive || exit 1 > cd / > umount /mnt > echo "fsck_ffs" >> $results to: > echo "restore" >> $results > time -ao $results sh -c 'cd /mnt && restore -rf $fsarchive && cd / && unm= ount /mnt' || exit 1 > echo "fsck_ffs" >> $results --=20 Peter Jeremy --x4pBfXISqBoDm8sr Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.14 (FreeBSD) iEYEARECAAYFAks/tAgACgkQ/opHv/APuIdY1wCgqCqdnZxuEidkv1lpZ5dn7vRL cDEAn2Qvq+H/kFxI2YheKWR5PWsHWvHh =+Tvm -----END PGP SIGNATURE----- --x4pBfXISqBoDm8sr--
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