On Friday 19 November 2010 19:19:34 David W Noon wrote: > On Fri, 19 Nov 2010 17:00:04 +0100, Peter Humphrey wrote about Re: > > [gentoo-user] migrating disks (from mounts to disklabels: > >On Friday 19 November 2010 14:42:23 Neil Bothwick wrote: > >> On Fri, 19 Nov 2010 10:52:50 +0000, Mick wrote: > >> > Also primary partitions which he does not seem to be using at all > >> > have a slight edge over logical. > >> > >> Do you have any data on this? I generally use all logical partitions > >> but could be persuaded to rethink. > > > >Well there must be one level of indirection on first access, since the > >start of the logical partition has to be looked up in a "primary" > >partition, but I can't imagine that being needed more than once per > >reboot. > > Correct. > > The same applies to LVM2 or EVMS logical volumes: a small "lookup" > penalty (a few milliseconds) when the filesystem is first > activated/mounted, and as fast as the drive itself thereafter.
Short of measuring the latency with some system (which I wouldn't know how) I have experimented with setting the /boot partition on primary and logical partitions and the difference (on a stopwatch) was measurable in seconds betweeen having said partition on a primary and having it on a logical. Furthermore, sda7 was slower than sda5. I haven't measured latencies for first mount and subsequent look ups. I thought that it would be the same every time a partition fs is being accessed, no? -- Regards, Mick
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