Date: Thu, 24 Jan 2013 22:46:37 +0200 From: Daniel Kalchev <daniel@digsys.bg> To: Borja Marcos <borjam@sarenet.es> Cc: FreeBSD Filesystems <freebsd-fs@freebsd.org>, freebsd-scsi@freebsd.org, Steven Hartland <killing@multiplay.co.uk> Subject: Re: Problem adding SCSI quirks for a SSD, 4K sector and ZFS Message-ID: <92BD25C7-FC6C-41AF-80AE-05AAD4CD4659@digsys.bg> In-Reply-To: <FF2FCD9E-0CA5-4030-8881-C866FA97CF1D@sarenet.es> References: <492280E6-E3EE-4540-92CE-C535C8943CCF@sarenet.es> <A71C9D2FA3984F6A84CED6DE3E21DDCF@multiplay.co.uk> <FF2FCD9E-0CA5-4030-8881-C866FA97CF1D@sarenet.es>
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On Jan 24, 2013, at 6:09 PM, Borja Marcos <borjam@sarenet.es> wrote: > Oh, sorrry for the confusion! I assumed that the da driver would = announce a 4 KB sector instead of the 512 bytes due to the quirks.=20 >=20 > Which brings an interesting question, I might have a potential time = bomb in my experimental machine at home. It's a ZFS mirror with two 500 = MB disks. One of the has 512 byte sectors, the other is "advanced = format".=20 If you did not create your zpool with ashift=3D12, then you have the = bomb already. Disks with different native sector size coexist quite = happily in the same zpool. If the storage does not lie, ZFS will in fact = use the largest 'sector size' and everything will be ok. Many (most) = advanced format drives however lie about their sector size and pretend = to have 512 byte sectors. If you create an zpool with such a drive and = an 'normal' 512 byte drive without explicitly requesting 4k alignment, = thing are bad. Daniel=
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