From mboxrd@z Thu Jan  1 00:00:00 1970
Message-ID: <e3cfb7288dab4e04229cce9d447750a6@hamnavoe.com>
To: 9fans@9fans.net
From: Richard Miller <9fans@hamnavoe.com>
Date: Tue,  4 Oct 2011 17:42:20 +0100
In-Reply-To: <dee9e9dd2eebb0dd2e8589398d4a1461@chula.quanstro.net>
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Subject: Re: [9fans] copying fossil filesystem to a bigger disk
Topicbox-Message-UUID: 3245e162-ead7-11e9-9d60-3106f5b1d025

> 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.

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.