From: erik quanstrom <quanstro@quanstro.net>
To: 9fans@9fans.net
Subject: Re: [9fans] copying fossil filesystem to a bigger disk
Date: Tue, 4 Oct 2011 12:45:58 -0400 [thread overview]
Message-ID: <6e6d01007f08aaf2fd598115982645dc@chula.quanstro.net> (raw)
In-Reply-To: <e3cfb7288dab4e04229cce9d447750a6@hamnavoe.com>
> > you can try rewriting it to step by 8k and retry the test.
>
> Bingo, thanks.
>
> I was still trying to figure out how to force the drive to sync
> as Dexen suggested (maybe using scsicmd to issue an ata FLUSH CACHE
> command?), but stepping by 8k does reveal a strong pattern.
you can either use the raw device to send raw write dma ext fua,
or you can explicitly turn off the cache.
flush cache flushes anything from the cache, so it can be misleading.
> Writing 25000 4k records stepping by 8k takes
> sector offset 1-7 mod 8: 27-30 sec
> sector offset 0 mod 8: 14-17 sec
>
> Conclusion: WD10EARS has 4k byte physical sectors but is pretty
> good at concealing it.
it's amazing how fast you can be if you don't care about losing data
on power loss. :-)
- erik
next prev parent reply other threads:[~2011-10-04 16:45 UTC|newest]
Thread overview: 66+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-24 0:20 slash
2011-09-24 8:07 ` David du Colombier
2011-09-24 8:34 ` Steve Simon
2011-09-29 23:54 ` slash
2011-09-30 8:31 ` Richard Miller
2011-09-30 8:54 ` Richard Miller
2011-09-30 9:44 ` Charles Forsyth
2011-09-30 14:06 ` erik quanstrom
2011-09-30 14:16 ` Ethan Grammatikidis
2011-09-30 14:00 ` erik quanstrom
2011-10-01 10:36 ` slash
[not found] ` <CAEaiYYzXCfB2KbnDzBHTXytrfQqGUCepRg5Aj-c14ZoEz5hHaw@mail.gmail.c>
2011-10-01 13:51 ` erik quanstrom
2011-10-01 15:27 ` slash
2011-10-01 16:14 ` erik quanstrom
2011-10-01 16:23 ` erik quanstrom
2011-10-04 11:28 ` Richard Miller
2011-10-04 11:52 ` Charles Forsyth
2011-10-04 12:01 ` Richard Miller
2011-10-04 12:05 ` erik quanstrom
2011-10-04 12:09 ` Charles Forsyth
2011-10-04 12:13 ` Charles Forsyth
2011-10-04 12:19 ` dexen deVries
2011-10-04 12:27 ` Richard Miller
[not found] ` <CAOw7k5i3i+w_=pUuFjUCnxH1Tp5U0vh3v7wFUoBddfML9xG+ag@mail.gmail.c>
2011-10-04 12:17 ` erik quanstrom
2011-10-04 12:30 ` Charles Forsyth
[not found] ` <CAOw7k5hGWG16a5fTjtXBEBd2-gt=XnhjEJKFNjdPrB46_6=dBg@mail.gmail.c>
2011-10-04 12:34 ` erik quanstrom
2011-10-04 12:05 ` erik quanstrom
2011-10-04 12:15 ` Richard Miller
2011-10-04 12:17 ` erik quanstrom
2011-10-04 12:17 ` erik quanstrom
2011-10-04 12:33 ` Richard Miller
2011-10-04 12:52 ` dexen deVries
2011-10-04 13:05 ` dexen deVries
2011-10-04 14:13 ` erik quanstrom
2011-10-04 15:56 ` Richard Miller
2011-10-04 16:00 ` erik quanstrom
2011-10-04 16:42 ` Richard Miller
2011-10-04 16:45 ` erik quanstrom [this message]
2011-10-04 17:52 ` Charles Forsyth
2011-10-04 18:05 ` dexen deVries
2011-10-04 18:24 ` Bakul Shah
2011-10-04 18:29 ` erik quanstrom
2011-10-03 23:07 ` slash
2011-10-06 7:35 ` Peter A. Cejchan
2011-10-07 10:49 ` slash
2011-10-07 11:15 ` Peter A. Cejchan
2011-10-07 13:03 ` Steve Simon
2011-10-10 10:32 ` Peter A. Cejchan
[not found] ` <CAEaiYYya5eq3CoVbbZGqPf91_kMEcbkCQ_8WEL4yakFdenek5g@mail.gmail.c>
2011-10-07 13:17 ` erik quanstrom
2011-10-10 2:32 ` slash
[not found] ` <CAEaiYYy36ydHfw=Tg2YC9x9gEW7=MAHF2C6-UVbgr36G-qv=rA@mail.gmail.c>
2011-10-10 3:11 ` erik quanstrom
2011-10-10 10:15 ` slash
[not found] ` <d0c02b8a1e36c9329902a1183192d732@chula.quanstro.>
[not found] ` <CAEaiYYxoHLgMZddGZ4gCPvW-GuqwRYzytXgfezoi+vjUgxx9tg@mail.gmail.c>
2011-10-10 13:17 ` erik quanstrom
2011-10-11 8:51 ` slash
2011-10-11 8:55 ` slash
2011-10-11 15:01 ` slash
2011-10-11 15:36 ` David du Colombier
2011-10-12 19:24 ` slash
2011-10-13 7:07 ` Peter A. Cejchan
[not found] ` <CAEaiYYxsUzf70Ffhd3hzsBZcMb5=2yhfSCv5-nJ+_27wYbJKig@mail.gmail.c>
2011-10-03 23:10 ` erik quanstrom
2011-10-04 0:02 ` erik quanstrom
2011-10-04 7:58 ` dexen deVries
2011-10-04 9:52 ` Richard Miller
2011-10-04 9:34 ` Richard Miller
2011-10-07 7:47 ` [9fans] io patterns erik quanstrom
2011-09-24 8:30 ` [9fans] copying fossil filesystem to a bigger disk Steve Simon
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