Re: New filesystem for Linux

From: H. Peter Anvin
Date: Sun Nov 05 2006 - 15:28:13 EST


Kyle Moffett wrote:
On Nov 04, 2006, at 18:38:11, Mikulas Patocka wrote:
But how will fdisk deal with it? Fdisk by default aligns partitions on 63-sector boundary, so it will make all sectors misaligned and seriously kill performance even if filesystem uses proper 8-sector aligned accesses.

Don't use a partition-table format that dates back to drives with actual reported physical geometry and which also maxed out at 2MB or so? Even the mac-format partition tables (which aren't that much newer) don't care about physical drive geometry.

Besides, unless you're running DOS, Windows 95, or some random ancient firmware that looks at your partition tables or whatever you can just tell fdisk to ignore the 63-sector-alignment constraint and align your partitions more efficiently anyways. But if you're dealing with hardware so new it supports 4k or 8k sectors, you really should be using EFI or something.

Cheers,
Kyle Moffett


Actually, DOS/Win9x should handle arbitrary alignment just fine (except possibly some very very old versions of DOS which assumed that the first four sectors of IO.SYS all fell within the same track -- but I'm pretty sure that the FORMAT and SYS programs would align it for you.)

-hpa
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