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From: John Robinson <john.robinson@anonymous.org.uk>
To: Linux RAID <linux-raid@vger.kernel.org>
Subject: Re: md-raid and block sizes
Date: Tue, 28 Dec 2010 11:45:15 +0000	[thread overview]
Message-ID: <4D19CDCB.4090208@anonymous.org.uk> (raw)
In-Reply-To: <AANLkTim_vvdzYpdgQitK0942h-cW-q14MLhooSoaBOeL@mail.gmail.com>

On 27/12/2010 19:02, Doug Dumitru wrote:
[...]
> The same rules apply to most SSDs.  Most SSDs prefer 4K alignment
> because of how the FTL (Flash Translation Layers) operate, even though
> <4K will sometimes still work pretty well.

If I remember correctly, it may be better to align on SSDs at a larger 
granularity, to the SSDs' erase block size, which may be up to 512K 
depending on the SSD, though I don't remember at all how well Linux 
filesystems, VFS, block layer drivers etc. handle SSD TRIM etc.

Cheers,

John.


  reply	other threads:[~2010-12-28 11:45 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-12-27 12:00 md-raid and block sizes D.S. Ljungmark
2010-12-27 19:02 ` Doug Dumitru
2010-12-28 11:45   ` John Robinson [this message]
     [not found] ` <AANLkTikWxCxVUO+O8MXRXRR7Y8R5xGC1Catv-EiNGcDj@mail.gmail.com>
2010-12-28  8:46   ` D.S. Ljungmark
2010-12-28 11:29     ` hansbkk
2010-12-28 11:45       ` Neil Brown
2010-12-28 11:50         ` Mikael Abrahamsson
2010-12-28 11:51         ` Roman Mamedov
2010-12-28 11:45       ` Roman Mamedov

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